JP2010127785A - Measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring device favorably detecting magnetic flux even when a distance between a detection part and a magnet is large. <P>SOLUTION: The measuring device 8 includes: a display means 10 displaying the speed of a vehicle; a circuit substrate 12 electrically connected to the display means 10; a case 13 accommodating the display 10 and the circuit substrate 12; a magnet 14 attached to a main axis 28 that rotates with a rotation cable 9 for transmitting a rotation of the speed of the vehicle; and a hole IC 15 serving as a detection part for detecting the rotation of the magnet 14. The hole IC 15 is disposed on the circuit substrate 12 and accommodated in the case 13. A projection 14 is provided on a surface of the magnet 14 facing to the hole IC 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an instrument device that displays the speed of a moving body, and more particularly to an instrument device that displays the speed of a two-wheeled vehicle.

A conventional instrument device transmits display speed indicating the speed of a vehicle, a circuit board electrically connected to the display means, a case storing the display means and the circuit board, and rotation of the speed of the vehicle. A magnet mounted on a main shaft that rotates together with the rotating cable, and a detection unit that detects rotation of the magnet. The detection unit is provided on the circuit board, and the detection unit is housed in the case. (For example, see Patent Document 1).
JP 2008-32615 A

  In the conventional instrument device, the magnet has a magnetic flux density concentrated on the corners of the magnet (on the outer peripheral side of the upper and lower ends of the annular or cylindrical shape), and in a direction perpendicular to the detection part of the lines of magnetic force emitted from the magnet. The traveling distance was short, the direction of the lines of magnetic force emitted from the magnet was oblique, and the magnetic flux density in the direction perpendicular to the detection unit was small. In particular, when a Hall element that detects magnetic flux in a perpendicular direction is used for the detection unit, the gap between the magnet and the Hall element has to be reduced in order to detect the magnetic flux satisfactorily. Thereby, in order to make the space | interval of the said magnet and the said Hall element small, the restriction | limiting has arisen in the position of the said circuit board which mounts the said detection part.

  Alternatively, in the conventional instrument device, a light emitting diode is mounted as a light source for illuminating the display means on the surface of the circuit board on which the display means is provided, and the display means of the circuit board is provided. The detector is mounted on the surface opposite to the side (the main axis side of the circuit board). As described above, since the components are mounted on both sides, the circuit board is expensive.

  Therefore, the present invention pays attention to the above-described problems, and an object thereof is to provide an instrument device that can detect a magnetic flux satisfactorily even if the distance between the detection unit and the magnet is large.

  The instrument device according to the present invention comprises a display means for displaying the speed of the vehicle, a circuit board electrically connected to the display means, a case for housing the display means and the circuit board, and rotation of the speed of the vehicle. A meter including a magnet mounted on a main shaft that rotates together with a rotating cable for transmission, and a detection unit that detects rotation of the magnet, the detection unit being provided on the circuit board, and the detection unit being housed in the case In the apparatus, a protrusion is provided on a surface of the magnet facing the detection unit.

  Further, the protrusion is formed in an annular shape so as to be concentric with the rotating shaft of the magnet.

  Moreover, the cross-sectional shape of the protrusion in the axial direction in which the magnet rotates is an angle formed by two sides.

  Further, the angle of the protrusion is an acute angle.

  As described above, according to the present invention, it is possible to provide an instrument device that can detect magnetic flux satisfactorily even when the distance between the detection unit and the magnet is large.

  FIG. 1 shows the basic configuration of the present invention, and will be described by taking a two-wheeled instrument device as a moving body as an example.

  The two-wheeled vehicle 1 includes a frame 2 made of metal such as aluminum, an internal combustion engine (engine) 3 that uses gasoline as fuel, a fuel tank 4 that stores gasoline, a seat 5 on which a driver of the two-wheeled vehicle 1 sits, and a front wheel 6. And two front forks 7 that rotatably hold the front wheel 6, an instrument device 8, and a rotating cable 9 that transmits the rotation of the front wheel 6 to the instrument device 8. The engine 3, the fuel tank 4, and the seat 5 are attached to the frame 2, and the two front forks 7 are attached to the frame 2 so as to be steerable to the left and right.

  Next, the instrument device 8 will be described with reference to FIG. The instrument device 8 includes a speedometer 10 that is a display means for displaying the speed of the motorcycle, a circuit board 12 that is electrically connected to the speedometer 10, a case 13 that houses the speedometer 10 and the circuit board 12, and a vehicle. The magnet 14 mounted on the main shaft 28 that rotates together with the rotating cable 9 that transmits the rotation of the front wheel 6, which is the rotation of the front wheel 6, the Hall IC 15 that is a detection unit that detects the rotation of the magnet 14, and the main shaft 28 can be rotated. And a bearing portion 29 to be held in the housing. Reference numeral 16 denotes a dial, and reference numeral 17 denotes a control unit that controls the speedometer 10.

  The speedometer 10 is a pointer-type meter provided with a pointer 18. The speedometer 10 includes, in addition to the pointer 18, a dial plate 16 having scales and characters (not shown) indicated by the pointer 18, and an instrument body 19 that rotationally drives the pointer 18.

  The dial 16 includes a through hole 20. The through-hole 20 passes through the rotary shaft 22 that connects the pointer 18 and the instrument body 19.

  The instrument main body 19 includes a cross coil instrument main body, a stepping motor, and the like, and is driven by a drive process of the control unit 17.

  The case 13 includes a back case 13a and a front cover 13b. The back case 13a and the front cover 13b are assembled so as to perform waterproof and dustproof functions for a motorcycle. In addition, it is not a complete sealing structure, and it is possible to ventilate the air inside and outside the case 13 by providing a filter (not shown) that does not transmit water but transmits gas. The back case 13 a does not transmit light, and is made of, for example, black synthetic resin, and forms the back side of the instrument device 8. The front cover 13b is made of a synthetic resin that transmits light, and is colorless in this embodiment. The front cover 13 b forms the front side of the instrument device 8.

  The magnet 14 has a disk shape, and a main shaft 28 passes through the center thereof. The magnet 14 rotates with the main shaft 28. The magnet 14 is magnetized, and a plurality of N poles and S poles are provided in the radial direction around the rotation center. In the present embodiment, the N pole and the S pole are combined to provide eight magnetic poles.

  The magnet 14 includes a protrusion 14 a on the surface facing the Hall IC 15. Further, the protrusion 14 a is formed in an annular shape so as to be concentric with the rotating shaft of the magnet 14.

  Further, the cross-sectional shape in the axial direction in which the magnet 14 of the protrusion 14a rotates is an angle 14c formed by two sides 14b.

  In the present embodiment, the angle r of the corner 14c of the protrusion 14a is an acute angle.

  The Hall IC 15 is mounted on the circuit board 12 and is electrically connected to a wiring pattern (not shown) provided on the circuit board 12. The Hall IC 15 includes a Hall element 15a and a protective portion 15b made of a synthetic resin. The protection unit 15b covers the hall element 15a in order to protect the hall element 15a. The Hall element 15a is a kind of sensor using a semiconductor and detects magnetism. In the present embodiment, the rotation of the magnet 14 is detected by detecting a change in the magnetic field accompanying the rotation of the magnet 14.

  The main shaft 28 is made of metal, and is rotatably supported by the back case 13a by a bearing portion 29. A concave portion 28a is provided on the opposite side of the main shaft 28 from the side on which the magnet 14 is provided. The end 9a of the rotary cable 9 is inserted into the recess 28a. The recess 28a has a quadrangular cross-sectional shape in the direction perpendicular to the longitudinal direction, and the end 9a inserted into the recess 28a also has a shape that matches the recess 28a. The rotation of the rotary cable 9 is transmitted to the main shaft 28, and the main shaft 28 rotates.

  The bearing portion 29 is also made of metal and has a cylindrical shape. The bearing portion 29 includes a flange portion 30 on the outer periphery. The flange portion 30 abuts around the hole 13c provided in the back case 13a, the bearing portion 29 is inserted into the hole 13c, and the bearing portion 29 is caulked. It is fixed. Reference numeral 31 denotes a retaining ring, which is made of metal and has a donut shape, and prevents the main shaft 28 from coming off from the bearing portion 29.

  The control unit 17 is an integrated circuit such as an IC, is mounted on the circuit board 12, and is electrically connected to a wiring pattern (not shown) provided on the circuit board 12. The control unit 17 includes a circuit unit 17a that is a main unit and a protection unit 17b that protects the circuit unit 17a. The protection unit 17b covers the circuit unit 17a in order to protect the circuit unit 17a.

  With the above-described configuration, the magnetic flux density that has been concentrated only on the corners of the magnet (the outer peripheral side of the annular or cylindrical end) is concentrated on the protrusions 14a, and the lines of magnetic force emitted from the magnets 14 are used. Thus, the instrument device 8 can be provided that can detect the magnetic flux satisfactorily even when the distance in the vertical direction with respect to the detector 15 is long and the distance between the Hall IC 15 and the magnet 14 is large.

  Since the gap between the magnet 14 and the Hall element 15 can be widened, the degree of freedom increases in the position of the circuit board 12 on which the Hall element 15 is mounted.

  In addition, since the gap between the magnet 14 and the Hall element 15 can be widened, the Hall IC 15 can be mounted on the surface of the circuit board 12 on which the display means is provided. The components can be mounted only on the circuit board, the inexpensive circuit board 12 can be used, and the cost can be reduced.

  In addition, the protrusion 14a should just be provided in the part in which a magnetic pole exists. However, when the magnetic pole is magnetized on the magnet 14 by forming the protrusion 14a in an annular shape so as to be concentric with the axis of rotation of the magnet 14 as in this embodiment, the protrusion is divided and provided. Compared to the above, it is not necessary to magnetize so as to correspond to the divided protrusions, and the manufacturing convenience is improved.

  Further, by setting the cross-sectional shape of the protrusion 14a in the axial direction in which the magnet 14 rotates to be an angle 14c formed by two sides 14b, the magnetic flux density can be easily concentrated on the protrusion 14.

  Further, by making the angle r of the corner 14c of the protrusion 14a an acute angle, the protrusion 14 can easily concentrate the magnetic flux density.

  In the above-described embodiment, the Hall IC 15 using the Hall element 15a is employed in the detection unit. However, the present invention is not limited to the above-described embodiment. Resistance effect element) or the like may be employed.

  In the above-described embodiment, the speedometer 10 is a pointer-type meter provided with a pointer 18, but the display means is not limited to the above-described embodiment. For example, a liquid crystal display element, an organic EL element, Alternatively, it may be a display means that employs a display element such as a fluorescent display tube.

  In the above embodiment, the rotation of the vehicle speed is taken out from the front wheel (hub) of the two-wheeled vehicle, but is not limited to the above embodiment, and is taken out from the transmission of the internal combustion engine 3, for example. It may be.

  In the above embodiment, only the speedometer 10 for displaying the speed of the vehicle is used. However, a liquid crystal display (display means) for displaying the travel distance of the two-wheeled vehicle may be provided. This liquid crystal display may display the remaining amount of fuel, engine cooling water temperature, time, etc. in addition to the travel distance described above.

Explanatory drawing of the two-wheeled vehicle carrying the instrument apparatus of embodiment of this invention. Sectional drawing of the meter apparatus of the embodiment. The fragmentary sectional perspective view of the magnet of the embodiment. Sectional drawing of the principal part of the magnet of the embodiment.

Explanation of symbols

9 Rotating cable 10 Speedometer (display means)
12 circuit board 13 case 13a rear case 13b front cover 14 magnet (detected body)
14a Protrusion 14b Side 14c Angle 15 Hall IC (Detector)
28 Spindle 29 Bearing part r Angle

Claims (4)

It rotates together with a display means for displaying the speed of the vehicle, a circuit board electrically connected to the display means, a case for housing the display means and the circuit board, and a rotating cable for transmitting the rotation of the speed of the vehicle. In an instrument device comprising a magnet mounted on a main shaft and a detection unit for detecting rotation of the magnet, the detection unit being provided on the circuit board, and the detection unit being housed in the case, An instrument device comprising a protrusion provided on a surface facing the detector. The instrument device according to claim 1, wherein the protrusion is formed in an annular shape so as to be concentric with an axis of rotation of the magnet. The instrument device according to claim 1, wherein a cross-sectional shape of the projection in the axial direction in which the magnet rotates is an angle formed by two sides. The instrument device according to claim 3, wherein the angle of the corner of the protrusion is an acute angle.

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