JPH06137890A - Movement part of measuring instrument for vehicle - Google Patents

Abstract

PURPOSE:To provide a movement part of a measuring instrument for vehicle, which is provided with a rotation detecting unit for detecting the rotation of an indicating needle and of which weather resistance and durability are improved and which can save the space. CONSTITUTION:A movement 1 has a stepping motor 3 as a driving source. A worm gear 5 is engaged with a rotary shaft 3a of the stepping motor 3, and a helical gear 7 is engaged with the worm gear 5. The center of the helical gear 7 is formed with an output shaft 9, and one end of the output shaft 9 is supported by a case 11 freely to turn, and the other end thereof is projected from a hole provided in the case 11, and an indicating needle 13 is fitted to the tip of the other end of the shaft 9. A rotating plate 15 having multiple vertical grooves 15a is fitted to the helical gear 7. An optical sensor 21, which consists of a light emitting element 17 and a light receiving element 19, is arranged close to the side surface of the rotating plate 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movement of an instrument for a vehicle, which is used in a speedometer, a tachometer, etc. and whose drive motor is constituted by a stepping motor (pulse motor) or the like.

[0002]

2. Description of the Related Art Conventionally, there are speedometers, tachometers, and the like that use a stepping motor in a drive portion of a pointer. The stepping motor is designed to be driven by a pulse signal based on the vehicle speed and engine speed digitized by various control devices. In principle, the stepping motor can obtain a rotation angle according to the input pulse number. Etc., it is generally driven by open loop control.

FIG. 4 is a sectional view showing a movement of a conventional vehicle instrument. As shown in the figure, the movement 1 has a stepping motor (pulse motor) 3 as a drive source as described above, and a worm gear 5 is fitted to a rotary shaft 3a of the stepping motor 3. Further, a helical gear 7 is meshed with the worm gear 5, and an output shaft 9 is provided at the center of the helical gear 7. One end of the output shaft 9 is pivotally supported by the case 11, the other end projects from a hole provided in the case 11, and a pointer 13 is attached to the tip thereof.

Since the movement 1 is configured as described above, for example, when a pulse signal corresponding to the rotation speed of the rotating portion of the vehicle is input to the motor 3 by a drive circuit (not shown), The rotary shaft 3 a rotates, and the helical gear 7 rotates via the worm gear 5. Then, the output shaft 9 rotates integrally with the helical gear 7, and the pointer 13 attached to the tip of the output shaft 9 indicates the scale of the dial (not shown) according to the rotation speed of the rotating portion. In this way, it is possible to obtain the rotation angle according to the number of input pulses.

[0005]

However, the stepping motor driven by such open loop control is disengaged when the rotation of the motor is temporarily stopped due to some physical factor such as a decrease in driving voltage or dust. The tone occurs. When the step-out occurs, there is a problem that the initial value of the control device is deviated and an error in the pointer of the instrument occurs.
In this case, if the stepping motor is driven by feedback control, the above-mentioned problem is solved, but as a vehicle-mounted instrument, its detection unit may be configured to satisfy weather resistance, durability, and space efficiency. It becomes important.

An object of the present invention is to provide a movement of a vehicle instrument equipped with a rotation detecting portion of a pointer which enables weather resistance, durability and space saving.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a movement of a vehicular measuring instrument in which the rotation of a motor is transmitted to an output shaft via a gear and a pointer attached to the output shaft is driven. A rotary plate having a large number of vertical grooves is attached to the output shaft, and an optical sensor including a light emitting / receiving element is arranged in the vicinity of a side surface of the rotary plate. Further, the movement of the vehicle instrument according to the present invention is characterized in that the rotating body and the gear attached to the output shaft are integrally structured.

[0008]

With the construction described above, the shaft of the motor rotates when an input signal is applied to the motor, and this rotational force is transmitted to the output shaft via the gear. Therefore, the output shaft rotates and the pointer attached to the shaft indicates the scale of the dial or the like corresponding to the input signal value of the motor. Further, when the output shaft rotates, the rotary plate attached to the shaft also rotates integrally, and the light emitted from the light emitting element arranged in the vicinity of the side surface of the rotary plate emits light to the groove of the rotary plate. The reflection characteristic changes depending on the difference from the non-exposed portion, and this reflected light is similarly received by the light-receiving element that is arranged close to the side surface of the rotating plate. Measure this change as the number of pulses,
The rotation angle of the rotation shaft can be known, and the detected rotation angle information can be fed back to the drive unit of the motor to obtain accurate rotation according to the input signal value.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the same or corresponding portions as those described in the related art.

FIG. 1 is a sectional view showing an embodiment of a movement 1 of a vehicle instrument according to the present invention. As shown in the figure, this movement 1 has a stepping motor (pulse motor) 3 as a drive source, and a worm gear 5 is fitted to a rotary shaft 3a of the stepping motor 3. In addition, the worm gear 5 has a helical gear 7
Are engaged with each other, an output shaft 9 is provided at the center of the helical gear 7, and one end of the output shaft 9 has a case 11
The other end projects from a hole provided in the case 11, and a pointer 13 is attached to the tip of the hole.

Further, the helical gear 7 fixed to the output shaft 9 has a large number of vertical grooves 15a as shown in plan view 2 in FIG.
The rotary plate 15 having the is attached to the helical gear 7 by an integral structure. Further, inside the case 11 adjacent to the side surface of the rotating plate 15, an optical sensor 21 including a light emitting element 17 including an LED or LD and a light receiving element 19 including a phototransistor or PD is arranged.

Next, the operation of the movement of the vehicle instrument according to this embodiment will be described. For example, when a pulse signal corresponding to the rotation speed of the rotating portion of the vehicle is applied to the motor 3 by a drive circuit (not shown), the shaft 3a of the motor 3 rotates. The rotation of the shaft 3a is transmitted to the helical gear 7 via the worm gear 5, and the output shaft 9 rotates accordingly. The output shaft 9 rotates by an angle proportional to the number of input pulses to the motor 3, and the pointer 13 attached to the tip of the shaft 9 indicates a scale such as a dial corresponding to the input signal value of the motor 3.

When the output shaft 9 rotates, the rotary plate 15 attached to the shaft 9 also rotates integrally, and the light emitting element 17 disposed in the vicinity of the side surface of the rotary plate 15.
The reflection characteristics of the light emitted from the rotary plate 15 are changed depending on the difference between the groove 15a and the non-groove portion of the rotary plate 15, and the reflected light is also similarly arranged on the side surface of the rotary plate 15 in the light receiving element 1.
It is received by 9. By measuring this change as the number of pulses, it is possible to know the rotation angle of the rotary plate 15, that is, the output shaft 9, and the detected rotation angle information is fed back to the drive unit of the motor for accurate rotation according to the input signal value. Can be obtained.

As another embodiment, the rotary plate 15 is
As shown in FIG. 3, the helical gear 7 is provided on both upper and lower surfaces, two optical sensors 21 are provided, and the upper and lower rotary plates 1 are provided.
The grooves 15a of 5 may be offset from each other. In this case, since the output signals having different phases can be obtained from the two optical sensors 21, the rotation angle detection accuracy can be further improved.

[0015]

As described above, according to the present invention,
Since the rotary plate is provided integrally with the gear of the output shaft and the rotation angle of the rotary plate is detected by the optical sensor, the indication accuracy of the vehicle instrument can be improved by feeding back the detection signal. Further, since the rotary plate is integrally formed with the gear, the cost is low, the weather resistance and the durability are excellent, the space can be configured in a small space, and the vehicle can be highly reliable.

[Brief description of drawings]

FIG. 1 is a cut side view of a movement of a vehicle instrument according to an embodiment of the present invention.

FIG. 2 is a partial plan view of the movement of the vehicle instrument shown in FIG.

FIG. 3 is a cut side view of a movement of a vehicle instrument that is another embodiment of the present invention.

FIG. 4 is a cut side view of a movement of a conventional vehicle instrument.

[Explanation of symbols]

 1 Vehicle Instrument Movement 3 Stepping Motor 3a Rotating Shaft 5 Worm Gear 7 Helmet Gear 7 Output Shaft 11 Output Shaft 11 Case 13 Pointer 15 Rotating Plate 15a Groove 17 Light-Emitting Element 19 Light-Receiving Element 21 Optical Sensor

Claims (2)

[Claims] 1. A movement of an instrument for a vehicle, wherein rotation of a motor is transmitted to an output shaft via a gear to drive a pointer attached to the output shaft. A rotary plate having a large number of vertical grooves on its side surface. Is attached to the output shaft, and an optical sensor composed of a light emitting and receiving element is disposed in the vicinity of the side surface of the rotary plate, and the movement of the vehicle instrument is characterized in that. 2. The movement of a vehicle instrument according to claim 1, wherein the rotating body and a gear attached to the output shaft are integrally structured.