JPH1030920A - Powerless rotation sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to achieve highly accurate detection and cost reduction by providing a specified angle of skew inclined from the axial direction to the tooth of a gear, and arranging each sensor along the same direction as the axial direction. SOLUTION: At the outside position of a gear 1, sensors 3 and 4 are provided in such a state that the sensors are separated by a specified gap (g), and also is a state that the sensors are separated from each other in the same direction as the axial direction of the gear 1 and overlap each other at the same position on the circumference. When the gear 1 is rotated, the first sensor 3 corresponds to the center of a gear tooth 2, and the second sensor 4 corresponds to the edge part of the tooth 2 with respect to the sensors 3 and 4. Therefore, output waveforms A and B outputted from the respective sensors 3 and 4 becomes the state, wherein the phase is deviated by the angle of skew θ. Therefore, when a gap (g) between the outer diameter of the gear 1 and the space between the sensors 3 and 4 is changed, the sensitivity of the output waveform is changed, and the phase between the respective output waveforms A and B is always constant different from the conventional device only by the change in sensitivity of the output waveforms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-powered type rotation sensor, and more particularly, to imparting a skew angle inclined from the axial direction to the teeth of a gear so that each sensor is arranged along the same axial direction as the axial direction of the gear. The present invention relates to a novel improvement for greatly simplifying the structure and adjustment as compared with the related art.

[0002]

2. Description of the Related Art Conventionally, a configuration shown in FIG. 3 has been adopted as a non-power-supply type rotation sensor of this type which has been used. That is, in FIG. 3, a gear indicated by reference numeral 1 is a gear rotatably provided by a rotating shaft (not shown).
Are alternately formed at a predetermined pitch. At the outer position of the gear 1, first and second sensors 3 and 4 are provided with a predetermined gap g, and each of the sensors 3 and 4 has a predetermined angle (phase angle) on the circumference of the gear 1. It is arranged in a state shifted by θ. Each of the sensors 3 and 4 includes a well-known core 5 and a detection coil 6 wound on the core 5.
And the groove 2A correspond to the sensors 3 and 4 alternately, so that the sensors 3 and 4 output two-phase output waveforms A and B as shown in FIG.

[0003]

The conventional non-powered rotation sensor has the following problems because it is configured as described above. That is, as is clear from FIGS. 4 and 5, since each sensor is provided with a phase shift in the circumferential direction of the gear, when positioning each sensor at a predetermined gap g and a predetermined angle θ, When g is large, the predetermined angle θ is small, and when the gap g is small, the predetermined angle θ is large, and it is extremely difficult to perform position adjustment work for positioning of each sensor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, by imparting a skew angle inclined from the axial direction to the gear teeth, each sensor can be made the same as the axial direction of the gear. It is an object of the present invention to provide a non-powered rotation sensor that is disposed along the axial direction and that greatly simplifies the structure and adjustment as compared with the related art.

[0005]

SUMMARY OF THE INVENTION A non-powered rotation sensor according to the present invention detects the movement of the teeth of a rotatable gear by a pair of sensors located outside the gear and having a detection coil, and detects the phase. In a non-powered rotation sensor configured to obtain different first and second output waveforms, the teeth have a predetermined skew angle inclined from an axial direction of the gear, and the sensors are arranged in the same direction as the axial direction. In this configuration, they are arranged apart from each other.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a non-powered rotation sensor according to the present invention will be described below with reference to the drawings. Note that the same or equivalent parts as those in the conventional example will be described using the same reference numerals. 1 and 2, a gear 1 is rotatably provided by a rotating shaft (not shown).
And grooves 2A are alternately formed at a predetermined pitch.

The teeth 2 and the grooves 2A formed on the outer periphery of the gear 1 are formed so as to have a predetermined skew angle θ inclined with respect to the axial direction C of the gear 1, as shown in FIG. The skew angle θ can be set arbitrarily. However, in the embodiment of FIGS. 1 and 2, the skew angle θ corresponds to the angular width of either the tooth 2 or the groove 2A.
Set to pitch.

At the outer position of the gear 1, first and second sensors 3, 4 are provided with a predetermined gap g therebetween, and these sensors 3, 4 are arranged in the same axial direction C as the axial direction C of the gear 1. In the plan view of FIG. 1, the sensors 3 and 4 are arranged at the same position on the circumference of each other so as to overlap each other.

Next, when the gear 1 rotates in the above-mentioned state, as shown in FIG. 2, the first sensor 3 corresponds to the center of the tooth 2 and the second sensor 4
Corresponds to the edge portion of the tooth 2, so that each sensor 3,
The output waveforms A and B output from FIG. 4 are out of phase by the skew angle θ as shown in FIG. Therefore, if the gap g between the outer diameter of the gear 1 and the sensors 3 and 4 is changed, only the sensitivity of the output waveform changes, and the output waveforms A and B
Is always constant, unlike the prior art.

[0010]

Since the non-powered rotation sensor according to the present invention is configured as described above, the following effects can be obtained. That is, even when adjusting the gap between the gear and the sensor, there is no change in the phase shift of the output signal, so that high-accuracy speed detection is possible. Further, since the arrangement of each sensor is along the same axis direction, a mechanism for holding each sensor is easy, which can contribute to cost reduction. further,
The difference in the output voltage gradient of each sensor can be freely changed only by adjusting the gap with the gear, so that it is possible to easily achieve cost reduction and easy adjustment at the time of assembly.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a non-powered rotation sensor according to the present invention.

FIG. 2 is a bottom view of the gear of FIG. 1;

FIG. 3 is a waveform diagram showing output waveforms from the sensors of FIGS. 1 and 4.

FIG. 4 is a plan sectional view showing a conventional non-powered rotation sensor.

FIG. 5 is a bottom view of the gear of FIG. 4;

[Explanation of symbols]

 Reference Signs List 1 gear 2 teeth 3, 4 sensor C axis direction θ skew angle 6 detection coil

Claims (1)

[Claims] Movement of a tooth (2) of a rotatable gear (1) is detected by a pair of sensors (3, 4) located outside the gear (1) and having a detection coil (6). In the non-powered rotation sensor configured to obtain first and second output waveforms (A, B) having different phases, the tooth (2) is inclined at a predetermined angle from the axial direction (C) of the gear (1). A non-powered rotation sensor having a skew angle (θ) and a configuration in which the sensors (3, 4) are arranged apart from each other in the same direction as the axial direction (C).