JPS59602A - Angle detector for rotating body - Google Patents

Abstract

PURPOSE:To perform high-precision angle detection through simple constitution by fitting a semicircle rotating plate to a rotating shaft to be measured, providing two fixed plates in the same shape with said plate, and detecting variation in the electrostatic capacity among them. CONSTITUTION:The rotating shaft 5 to be measured is fitted with the semicircular disk 1 and the plates 2a and 2b of the same shape with the disk 1 are fixed to a main body 5 at 90 deg. to each other. The electrostatic capacities between the rotating plate 1, and fixed plates 2a and 2b vary according to the rotation of the rotating shaft 5. In this case, the electrostatic capacities in the form of voltage vary from 0 to a maximum and from the maximum to 0 according to the rotation of the shaft 5, so a specific circuit detects the angle of the rotating shaft 5. Thus, the high-precision angle detection is carried out.

Description

[Detailed description of the invention] The present invention relates to a rotation angle detection device for a single rotating body.

A rotary encoder is generally used to detect the angle of a rotating body. There are two types of rotary encoder fK: an incremental type for detecting the amount of 10 rotations, and an absolute type for detecting the angle of one rotation. The latter absolute method can detect the amount of one rotation and is functionally superior, but it has the drawbacks of being expensive and requiring a large number of signal processing steps.

Furthermore, precise control of a one-rotation machine basically requires detecting the movement of the final end of the load shaft, but the structure of the automatic machine (
It may be difficult to install a rotary encoder depending on the space available. As a result, the adjustment standards for a single machine, control (hardware), and software become unclear during debugging of the actual machine during development or production of a single-rotation machine, making precise adjustment and control difficult.

An object of the present invention is to provide a device for detecting the rotation angle of a rotating body that facilitates the detection of the angle of a single rotating body and that is miniaturized to enable automatic machine control and feedback control during machine debugging. It is.

The gist of the present invention is to connect a semicircular rotating plate to a rotating shaft to be measured, install a fixed plate that is electrostatically coupled to the rotating plate,
The point is that the amount of rotation of the rotating plate is detected as a change in capacitance.

The present invention will be explained in detail below with reference to FIG.

FIG. 1 shows an embodiment of the rotation angle detection device of the present invention.

In the figure, the rotation axis 11 is the rotation axis to be measured. The measuring rotating shaft 5 is coupled to the rotating shaft 11 via the Nicanopring 1o. The measurement rotation shaft 11 is insulated from the measurement rotation shaft by an insulator 9 .

A disk 1 having a semi-circular plate shape is directly connected to a measuring rotation shaft 5 and rotates together with the rotation shaft 5. The measurement rotation shaft 11 is fixed to the main body 8 via insulated slide bearings 6 and 7, and is rotatable once.

A semicircular notch 20Q is provided at the center of the end face 20 extending in the diameter direction of the semicircular fixing plate 2a.

The radius of this notch 200 is set larger than the radius of the rotating shaft 50. The notch 2oα is fixed to a device such that it does not come into contact with the rotating shaft 5 and that the rotating shaft 5 is sandwiched therebetween. There are two protrusions on the shoulder of the end face portion 20 of the fixing plate 2acr, and one part of the fixing rod 4α is fixed to the protrusions (-1).Furthermore, the other end of the fixing rod 4α is fixed to the main body via an insulating pusher s5a. In this way, the fixing plate 2α is fixed to the main body 8.

A conductive layer is formed on the surface of the fixed rod 4α and serves as an electrode. The terminal 3α becomes a terminal for taking out electricity from the electrode 4.

The fixing plate 2b has a similar structure to the semicircular fixing plate 2α. That is, they have the same radius, have the lake surface part 21, have the notch part 21h of the same radius, and are fixed to the main body 8 via the fixing rod 4b which also serves as an electrode and the insulating pusher 5A.

The fixed plate 2α and the fixed plate 2b are installed at positions adjacent to the rotary plate 1, and the fixed plate 2a and the fixed plate 2b are fixed at positions forming an angle of 90° with each other.

Under the positional relationship between the fixed plate 2a and the fixed plate 2b, 1
The rotating plate 1 rotates together with the rotating shaft 5. When the rotating body rotates 10 times, the rotating plate 1 and the fixed plate 2a and the rotating plate 1 and the fixed plate 2b rotate once.
The capacitances Cα and cb between the two change. The capacitances C'a and C'b change depending on the rotation angle of the rotary plate 10, and the rotation angles of the rotary shafts 11 and 5 can be detected by detecting the capacitance.

The output terminal for taking out the electrical signal from the rotating plate 1 is 1.
It is formed via the rotating shaft 5 using a brush or the like. Furthermore.

The fixing rods 4g and 44 having conductive layers on their surfaces do not come into direct electrical contact with the main body 8 and are insulated. The method of taking out the terminal and the method of insulating it from the main body are generally known.

FIG. 2 is a diagram explaining how the capacitances (,'a, (,'b) change between the fixed plates 2α, 27 and the rotating plate 1 due to 10 rotations of the rotating plate. (A), ( c), (e),
(g) The figure is a diagram of the relationship between the rotating plate 1 and the fixed plate 2α, (b)
To the).

(Figure 1 is a diagram showing the relationship between the rotating plate 1 and the fixed plate 2b.

The initial state of the rotary plate 1 is as shown in FIG.
The positions are different by 0° (the positions are different by 90° from the fixed plate 2b).

In this initial state, when the rotation angle is 0°.

Figures (A) and (C11) are shown respectively.The shaded areas are the overlapping parts.When rotated by 90 degrees from the initial state.

(/], to) Figure. When rotated by 180° (E)
, (to) become a figure. When rotated by 270°, (g), (
c) It becomes a diagram.

Now, let Sa be the overlapping area between rotating plate 1 and fixed plate 2a (referred to as 7 overlapping area), and St be the overlapping area between rotating plate 1 and fixed plate 2h (referred to as 8 overlapping area). The obtained capacitances C'a and C'h are:
Omitted.

becomes. Here, ε・ is the dielectric constant in air, and D・ is the rotating plate 1.
and the fixed plate 2α, and Db indicates the gap size between the rotary plate 1 and the fixed plate 2h.

(11, (In formula 21, 1 overlap area Sa, 5b changes linearly depending on the rotation angle, so the capacitance 1iitca
, (,'b is a value proportional to the rotation angle. Thus, the rotation angle can be detected by detecting the electrostatic capacity.

Figures 3 (A) and (0) show the capacitance characteristics where the horizontal axis represents the 10 rotation angle of one rotating plate and the vertical axis represents the capacitances C″a, C, and 6.Characteristic 13α is C′ Characteristics of a, characteristics 1
54 indicates the characteristics of C6. In the characteristic of Cα, o→18
Cα increases linearly at a° and decreases linearly from 180°→36o0. Similar characteristics will be shown below in units of 180°.

In terms of cb characteristics, cb increases linearly from 90° to 270°, and decreases linearly from 270° to 450°. Similar characteristics will be shown below in units of 180°.

Figure 5 (Ol, 0', 180°, s6r; , -
The value cth of C′b at the position of −−・− is
When the chQ value is cb>cth, it is in the range of 0 to 180°, and when cb≦cthO,
The range is from 180° to 560°. Therefore, Cb and ct
The angle at that time can be detected from the value of Cα based on the size comparison with h.

FIG. 4 is a diagram showing an embodiment of the rotation angle detection sentry. The capacitance/positive conversion circuit 15α takes the capacitance Cα from the terminal 4a and the terminal 12 (which is a lead-out terminal from the rotating plate 1 obtained from the rotating shaft 5) and converts it into a voltage. The capacitance/voltage conversion circuit 15jS has a capacitance of 1ll(,'
Convert a to input voltage.

Amplifiers 16a and 16B are capacity/voltage conversion circuits 15α
.

The output of 15b is taken in and a predetermined width is increased.

The AD converter 17 samples and holds the output of the amplifier 16a, and then performs AD conversion. The angle conversion circuit w118 converts the output of the AD converter 1D into an angle under the control of the comparator 21.

The comparator 21 compares the output Vb of the amplifier 16b with the reference value Vcc.
The magnitude is compared with the threshold value Vth given from .

Outputs 1 when Vb > Vth, and outputs 10 when Vb≦yth. This 1. Q is angle conversion circuit IBK
Is it input as a control signal and is between 0° and 180°? 1
It is used to determine whether it is in the range of so' to 660Q.

The decoder 19 takes in the output of the angle conversion circuit 1B.

The angle is interpreted based on the characteristics according to FIG.

The display 20 displays the decoding angle of the decoder 19.

Furthermore, the angle decoded by the decoder 19 is taken into another automatic control system and used for various controls.

FIG. 5 shows a sectional view of the angle detection device shown in FIG.

Identical symbols indicate the same instructions.

No special explanation is necessary.

FIG. 6 is a diagram showing an embodiment in which the number of fixed plates is increased by one for each fixed plate and the number of rotary plates is accordingly increased compared to the embodiment shown in FIG. 5.

In Fig. 6, there are six rotating plates 1 and two rotating plates 1'.

1' is attached to the rotating shaft. In addition to the fixed plate 2α, a pair of fixed plates 2a' is provided, and a rotary plate 1' is installed between the fixed plates 2a and 2a'. In addition to the fixed plate 2b, a pair of fixed plates 2b' is provided, and a rotary plate C is attached between the fixed plates 2b and 2b'. And rotating plate 1 and fixed plate 2
a1 Rotating plate 1'i Fixed plate 2α1 Rotating plate 1' and fixed plate 2α
'L--further, the one-rotation plate 1 and the fixed plate 2b.

Five capacitors are connected in parallel between the fixed plate 2, the rotary plate 1#, and the fixed plate 2'.

The characteristics of the six parallel-connected capacitors tend to be as shown in FIG. 5, allowing angle detection. In this example,
Three capacitors are used, which has the advantage of improving detection accuracy.

According to the present invention, highly accurate angle detection is possible with a simple configuration〇

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the detection device of the present invention. Figure 2 U) ~ Example is a diagram explaining the overlapping area of rotation angles,
Fig. 3 (a), (cap detection characteristic diagram) Fig. 4 is an embodiment of the detection circuit, Fig. 5 is a sectional view of the fifth embodiment of Fig. 1, and Fig. 6 is a diagram of the detection device of the present invention. It is a sectional view of another embodiment. 1...Rotating plate s 2'' * 2b '' fixed plate;
15a, 15j! l-・. Capacity/voltage conversion circuit, 18... Angle detection circuit, 19.
・. Decoder, 21... comparator. Representative Patent Attorney Bo 1) Li. '-*”-1 year old 5
Illustration 6

Claims (1)

[Scope of Claims] 1. A semicircular rotary plate connected directly or indirectly to a rotating shaft to be measured, and a rotating plate fixed at front and rear positions along the rotating shaft independently of the rotating shaft. The first rotary plate is installed in the same direction and has the same shape as the semicircular shape of the rotary plate. a second fixing plate;
means for detecting the rotation angle of the rotating shaft to be measured by capturing the electrostatic coupling state between the rotating plate and the first fixed plate and the electrostatic coupling state between the rotating plate and the second fixed plate; An angle detection device for a rotating body consisting of: 2. Above 1. 2. The angle detecting device for a rotating body according to claim 1, wherein the second fixing plates are fixed at positions 90° different from each other in the vertical direction of the rotation axis.