JPS6230967A - Speedometer for vehicle - Google Patents

Abstract

PURPOSE:To obtain a lightweight speedometer for vehicles with no resistance to the running of vehicles, by generating an induction force between a rotor magnet and an induction plate to turn a pointer against a return spring using a rotation torque of a motor. CONSTITUTION:A vehicle speed sensor 47 detects the vehicle speed and outputs a pulse signal corresponding to the vehicle speed. A driving circuit 48 outputs a motor drive pulse according to the pulse signal. Consequently, a rotor magnet 41, a disc 43 and a drive shaft 42 rotates together at a speed corresponding to the vehicle speed. This generates a rotary induction force at an induction plate 24 corresponding to the vehicle speed to turn the induction plate 24, a pointer shaft 21 and a pointer 22 together against the energized force of a return spring 23. The pointer 22 stays at a position where balance is reached between the induction force and the energized force to point to a speed value on a dial plate 31. On the other hand, an odometer 3 is turned with the drive shaft 42 through gear shifts 51 and 52 to display a running distance. A larger distance can be set between two opposed end faces of the disc 43 with the magnet 41 fastened thereon and the induction plate 24 to yield a demagnetizing effect of the magnetic force by the magnet 41.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a vehicle speedometer that does not use a flexible cable to mechanically transmit wheel rotation. (Prior art and its problems) In conventional vehicle speedometers, wheel rotation is mechanically transmitted via a flexible cable to rotate a magnet rotor inside the instrument body, and the magnetic rotor and guide plate are connected to each other. The inductive force generated by the eddy current generated between the two rotates the pointer to display the vehicle's running speed. The flexible wire of such a speedometer is resistant to rotation.

[Since the friction is large, it creates resistance to the rotation of the axle, which in turn creates resistance to the running of the vehicle, contributing to reduced fuel efficiency. Furthermore, since flexible wires cannot be bent extremely, there is a problem in that the layout is restricted. On the other hand, an electric speedometer that uses the vehicle speed detection signal from the vehicle speed sensor to rotate the pointer and display the vehicle speed eliminates the problems of the mechanical speedometer described above, but When an odometer that displays the number of miles traveled is provided, an odometer 11 movement circuit for rotating the odometer is required. Therefore, there is a problem that the configuration of the speed H1 becomes 4-1, resulting in an increase in size and weight. (Object of the Invention) The present invention has been made in view of the above circumstances, and is an easy-to-configure and lightweight vehicle speed H that does not affect the running resistance of the vehicle.
The purpose is to provide 1. (Means for Solving the Problems) In order to achieve the above object, the present invention provides a drive shaft which is disposed coaxially with the pointer shaft provided with the pointer and the return spring, and which is rotatable with respect to the pointer shaft. A motor having a rotating shaft connected to the motor, a rotor magnet provided on either the finger pin shaft or the drive shaft, a guide plate provided on the other of the pointer shaft or the drive shaft, and detecting vehicle speed. and a drive circuit that rotates the motor in synchronization with the vehicle speed based on a vehicle speed signal from the vehicle speed sensor, and rotates the pointer against the return spring by one torque of rotation of the motor. The structure is such that the guiding force is generated between the rotor magnet and the guiding plate. (Example) Hereinafter, a first example of the present invention will be described based on the drawings. Fig. 1 shows a speedometer for a vehicle to which the present invention is applied, and in the figure, 1 is an instrument case, and inside the case 1 is a speed indicator 2 and a speed indicator 2, which is installed in a manner similar to a conventional mechanical speedometer. A distance indicator (odometer) 3 is provided. That is, a pointer shaft 21 is rotatably provided in the center of one end side (the right end side in the figure) of the case 1, and one end 21a of the pointer shaft 21 extends outward from one end surface 1a of the case. The extending end 21
A pointer 22 that displays vehicle speed is fixed to a. Further, a dial 31 on which the number of speeds supported by the pointer 22 is written is fixed to one end surface 1a of the case j. A return spring 23 is provided at approximately the middle portion of the finger pin shaft 21 in the axial direction, and the return spring 23 biases the pointer shaft 21 in a predetermined rotational direction so that the pointer 22 is directed in a direction in which the vehicle speed is 0. is energized by Further, a substantially bowl-shaped guide plate 24 is fixed to the other end 21b of the pointer shaft 21 located inside the case 1. A rotor magnet 41 is provided within this guide plate 24 . The rotor magnet 1 41, which is magnetically coupled to the guide plate 24 and generates a rotational induction force on the guide plate 24, is disposed as follows. That is, a drive shaft 42 is provided at the center of the other end of the case 1 coaxially with the pointer shaft 21 and rotatable with respect to each other.
is fixed, and an annular rotor magnet 41 is fixed to the end face of the disk 43. This rotor magnet 1-41
A stator coil 45 is provided inside. The stator coil 45 is connected to case 1. It is supported by being fixed to one end surface of an arm member 32 fixed to both side walls of. The rotor magnet 41 and the stator coil 45 constitute a motor 46. The motor 46 is equipped with a vehicle speed sensor 47 that detects vehicle speed using an optical or magnetic method.
The motor is rotated by a motor drive pulse output from a drive circuit 48 in response to a pulse signal from the drive circuit 48. Note that in this case, the drive shaft 42 serves as the rotation shaft of the motor 46. On the other hand, the odometer 3 is provided at a predetermined location in the case 1, and the odometer 3 is connected to the drive shaft 42.
It is designed to be rotated via gear shafts 51 and 52. (Function) Next, the function of the vehicle speedometer having the above configuration will be explained. Vehicle speed sensor 47 detects vehicle speed and outputs a pulse signal according to the vehicle speed. The drive circuit 48 outputs motor drive pulses in response to pulse signals from the vehicle speed sensor 47. Then, the rotor magnets 1 to 41, the disk 43 and the drive shaft 42
rotates as a unit at a rotational speed that corresponds to the vehicle speed. thus,
A rotation guiding force is generated in the guide plate 24 according to the vehicle speed, and the guide plate 24, pointer shaft 21, and pointer 22 are moved by a return spring 23.
It rotates in one body against the urging force of. The pointer 22 comes to rest at a position where the guiding force and urging force are balanced, and the dial 31.
Two speed numbers are indicated. On the other hand, the odometer 3 is rotated by the drive shaft 42 via the gear shafts 51 and 52, and the mileage is displayed. In addition, the disk 4X□3 to which the rotor gear 1-41 is fixed
By increasing the distance between the opposing end faces of the rotor magnets 1 to 41, the magnetic force of the rotor magnets 1 to 41 can be demagnetized. FIG. 2 shows a second embodiment of the vehicle speedometer of the present invention, in which a rotor magnet 1 41' is fixed to one end of a drive shaft 42, and a stator coil 45' is connected to the rotor magnet 1.
It is provided between the outer circumferential surface of the guide plate 41 and the inner circumferential surface of the guide plate 24 . Further, the disk 43 corresponding to the first embodiment is not used. According to such a configuration, the magnetic force acting on the guide plate is controlled by the magnetic force of the stator coil 45, and the deflection of the pointer can be adjusted without adjusting the distance between the rotor magnet 1 41 and the guide plate 24. can do. FIG. 3 shows a third embodiment of the vehicle speed H1 of the present invention,
A guide plate 24' is fixed to one end of the drive shaft 42, and a rotating shaft 468' of a motor 46' is connected to the other end. The motor 4G' is fixed to the other end surface 1b of the case, and is rotated by motor drive pulses output from the drive circuit 48. Further, the other end 21) of the pointer shaft 21 is magnetically coupled to the guide plate 24'.
''-ta magnet 41'' is fixed. (Effects of the Invention) As detailed above, according to the vehicle speed R1 of the present invention,
a motor having a rotary shaft connected to a drive shaft which is arranged coaxially with the pointer shaft provided with the pointer and the return spring so as to be rotatable with respect to each other; and a motor provided on either the finger hook shaft or the drive shaft A rotor magnet, a guide plate provided on the other of the finger shaft or the drive shaft, a sensor 9' for detecting vehicle speed, and a drive for rotating the motor in synchronization with the vehicle speed based on a vehicle speed signal from the vehicle speed sensor. circuit, i
11. An induction force for rotating the pointer against the return spring is generated between the rotor magnets 1 and the guide plate by the rotational torque of the motor, so that it does not cause running resistance of the vehicle, and it is equipped with an odometer. Even in this case, an odometer drive circuit is not required, and the configuration is simple and lightweight. Further, a simple frequency dividing circuit can be used in place of the frequency converting circuit used in the conventional electric speed d1, which has the effect of simplifying the control circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a vehicle speedometer according to the present invention, FIG. 2 is a block diagram showing a second embodiment of a vehicle speedometer according to the present invention, and FIG. 3 is a block diagram showing a second embodiment of a vehicle speedometer according to the present invention. FIG. 3 is a configuration diagram showing a third embodiment of a speedometer; 1... Case, 2... Speed indicator, 3... Odometer, 2]-... Finger Φ 1 axis, 22... Pointer, 23... Return spring, 24. 24'... Guidance plate, 41. 41'
, 41'... To rotor magnet 1, 42... Drive shaft, 46. 46'... Motor, 46a'... Rotating shaft, 4
7. Vehicle speed sensor, 48. Drive circuit.

Claims (1)

[Claims] 1. A motor having a rotary shaft connected to a drive shaft which is coaxially and rotatably arranged with a pointer shaft provided with a pointer and a return spring, and a rotor provided on either the pointer shaft or the drive shaft. A magnet, a guide plate provided on the other of the pointer shaft or the drive shaft, a sensor that detects vehicle speed, and a drive circuit that rotates the motor in synchronization with the vehicle speed based on a vehicle speed signal from the vehicle speed sensor. A speedometer for a vehicle, characterized in that an induction force for rotating the pointer against the return spring is generated between the rotor magnet and the guide plate by the rotational torque of the motor.