JPS61266915A - Magnetic rotary encoder - Google Patents

Abstract

PURPOSE:To obtain a small-sized rotary encoder which is adjustable by providing the magnetic disk of each unit with three magnetic tracks. CONSTITUTION:The center magnetic head 15'' is moved in a radial direction of a magnetic disk 12 and aligned with the 2nd center magnetic track 12''; and a magnetic sensor is rotated around the center magnetic head 15'' to position magnetic heads 15' and 15''' on both sides on the 1st and the 2nd magnetic tracks 12' and 12''' on both sides. The position of the magnetic track for absolute value detection of the magnetic disk 12 of the 1st unit is detected by the magnetic sensor with 1/8 resolution. The rotation is transmitted to the magnetic disk of the next unit at a 1/8 deceleration ratio and the rotational position of this magnetic disk is also detected by the magnetic sensor similarly.

Description

Detailed Description of the Invention A00 Purpose of the Invention E1. INDUSTRIAL APPLICATION FIELD This invention relates to a magnetic rotary encoder, and particularly to an absolute type encoder capable of detecting absolute values.

E2. Problems to be Solved by the Prior Art and the Invention A magnetic rotary encoder having a magnetic track on a magnetic disc attached to a shaft and a rotational position detecting means disposed close to the magnetic disc is known in a colored type. However, when trying to increase resolution with a single magnetic disk, the outer diameter of the magnetic disk becomes thick (which makes it difficult to miniaturize. Also, the outer diameter cannot be increased. If an attempt is made to increase the resolution, the magnetic poles become fragmented, resulting in the problem of magnetic interference (Japanese Patent Laid-Open Nos. 57-85193 and 58-48196).

Conventional magnetic encoders have a problem in that the resolution cannot be changed.

The purpose of this invention is to propose a magnetic rotary engine, -2-da, which can solve the above-mentioned problems.

0 Structure of the Invention Row 16 Means for Solving the Problems The magnetic encoder of the present invention includes a magnetic disk having three concentrically arranged magnetic tracks, and three magnetic disks corresponding to these magnetic tracks. In adjusting the position relative to the magnetic sensor B in which the magnetic head is arranged linearly, first, the central magnetic head (15') is moved in the radial direction of the magnetic disk, and the magnetic head (15') is moved to the central second magnetic track (12''). Match with
, then rotate magnetic sensor B around the central magnetic head (15"), and rotate the magnetic sensor B on both sides (15").
(15”/) on both sides of the first and second magnetic tracks (
12') (12) is made to match the positions of (12') and (12') respectively.

In addition, in order to avoid magnetic interference between the magnetic trunks, there is a necessary and sufficient distance between them. Furthermore, if miniaturization is required, this can be achieved by placing a high magnetic permeability material between the magnetic tracks.

Row 20 action The position (absolute value) of the magnetic track for detecting the absolute value of the magnetic disk of the first unit is detected by the magnetic sensor B with a resolution Z. Then, the reduction ratio 4 is applied to the magnetic disk of the next unit.
Rotation is transmitted to the magnetic disk, and the rotational position of this magnetic disk is similarly detected by a corresponding magnetic sensor. In this way, when the number of units is n, the resolution is Kn.

Row 3. Embodiment In FIG. 1, (1) is a shaft to which rotation is transmitted from the outside, (2) is a magnetic disk fixed to the shaft (1), and (3) is a first gear fixed to the shaft (1). The shaft (1), the magnetic disc (2), and the first gear (3) constitute a first magnetic disc wheel (4).

The first magnetic disc (2) includes a magnetic track made of a magnetic material,
Alternatively, magnetic tracks may be formed on the surface of a non-magnetic material by plating or vapor deposition. And the first magnetic disk car (4)
is rotatably supported by a first body (5) that supports the shaft (1) with a bearing or the like. (6) is a magnetic sensor A placed close to the first magnetic disk (2).
It is fixed to the wall of the body (5).

The left surface of the first magnetic disk (2) is provided with two magnetic tracks (2') (2+), as shown in FIG. The magnetic track (2') forms a pattern with a resolution Z, which is one rotation divided into 10.
2') forms a magnetic pattern indicating the reference position of one rotation. The magnetic sensor A (6) that detects the positions of these magnetic tracks is connected to the magnetic track (2') and (
The magnetic sensor A (6) has magnetic heads (6') and (69) corresponding to the magnetic trunk (2"), and the magnetic sensor A (6) is arranged so that the gap between the magnetic trunk and the magnetic head is a predetermined distance as shown in FIG. The magnetic disk is arranged close to the first magnetic disk (2).

Again, in FIG. 1, (7) is a large gear A that meshes with the first gear (3), and is fixed to the shaft together with a small gear A (8) to form an intermediate gear A (9).

This intermediate gear A (9) is rotatably supported by the first body (5). The pinion A (8) is the first
It is fixed to a shaft portion that projects outside of the body (5).

C1111 is a second large gear, which is fixed to the shaft together with a second small gear (11) and a second magnetic disk (12) to form a second magnetic disk wheel (13). (14) is a second magnetic disc wheel (13) that rotatably supports this second magnetic disc wheel (13).
The body is provided with a retaining part (14) on the left end periphery thereof to be connected and fitted with the first body (5).

(15) is a magnetic sensor B placed close to the second magnetic disc wheel (13), and is fixed to the wall surface of the second body (14). The second magnetic disk (12) has a fifth magnetic disk on its left surface.
Three magnetic tracks (12') as shown in figure (A)
(12'') (12 common), and each of these magnetic tracks has a recognizable pattern of 0 or 1 corresponding to the numbers 0 to 7, which are divided into 8 parts of one revolution, as shown in the same figure (B). In addition, the 3 digits from IIh in the same figure (B) correspond to the magnetic trunks (12) to (12) in the same figure (A), respectively.
corresponds to

Magnetic track (12° is divided into 8 parts, (12°) is divided into 4 parts,
(12'/) is divided into two parts and matched in phase as shown in the figure, and constitutes a magnetic track for absolute value detection.

Magnetic sensor B (15) has three magnetic heads (15) (
15") (15 many), as shown in Figure 6,
These magnetic heads (15') (15') (1
5') respectively magnetic tracks (12') (12
°) (12+) and facing each other with a predetermined gap between them.
A magnetic sensor B is fixed to the second body (14) in FIG.

In Fig. 1, (16) is a large gear B that meshes with the second small gear (11), and this large gear B and a small gear B (17) integrally fixed to the shaft constitute an intermediate gear B. , this intermediate gear B (17) is rotatably supported by the second body (14). Specifically, the shaft of this intermediate gear B (17) is supported by a bearing provided on the second body (14).

The second body (14) is a cylinder with an outer diameter of Φ as a whole, and includes a disk-shaped wall (14a) that rotatably supports the second magnetic disk wheel (13) and the intermediate gear B (18). 14b) and has a barrel-shaped container. The second large gear αω and the small gear B (17) are protruding from the second body (14) of the barrel-shaped container.
) are stacked and connected to the first body (15) as shown in FIG.
The shape of the engaging portion (14) is determined so that it meshes with (8).

The second large gear (to) to the intermediate gear B (18) constitute a first unit (19) as a whole. and,
The first gear (3), the large gear A (η, the small gear A (8), and the second The reduction ratio of the reduction gear train consisting of the large gear α is fixed.

(19''') is a second unit whose structure is the same as the first unit (19), and by stacking it on the first unit (19) from the right side as shown in the figure, the first unit (19) pinion B (17), the second unit) (1
9') and the large gear B (16') mesh with each other.

Then, the second magnetic disk (12) of the first unit (19)
) so that the rotation of the second pinion (11) is reduced in speed and transmitted to the magnetic disc of the second unit (19').
The reduction ratio of the reduction gear train consisting of large gear B (16), small gear B (17), and large gear B (16') is determined. Note that the large gear B (1B) and the large gear B (1B) have the same number of teeth and the same shape.

(19') (19 now) are respectively the second unit (1
The 3rd and 4th units have the same structure as (19), and are marked with a dash to separate them from the 1st unit, but the structure is the same. By stacking them one after another, the rotation of the previous magnetic disk on the left side is decelerated by 3 and transmitted to the magnetic disk of that unit.

Note that when each unit is stacked and connected, the rotational positions of the gears are adjusted so that the reference points of the magnetic discs of adjacent units are in phase, and the units are connected and fitted together.

(20) is a cover fitted on the right side of the fourth unit (20').

1st unit) (19) to 4th unit (19”/
) The three magnetic tracks (12') (12'') (12 common) of the second magnetic disk (12) are the 51st!
As shown in the figure, magnetic heads (15') (15
') (15') is the force (, its The positional relationship is adjusted as follows (see Figure 9).

Prior to adjustment, the three magnetic heads (15'>(15'') (15th order) provided on the magnetic sensor (15) are arranged on one straight line X-X. Adjust the magnetic sensor (15) by moving it in the radial direction of the second magnetic disk (12) so that the second magnetic head (15") is aligned with the second magnetic track (12), and then The magnetic sensor (15) is rotated around the second magnetic head (15") to connect the first magnetic head (15"), the third magnetic head (15") and the first magnetic track (12") to the third magnetic track (15"). 12').

The operation of the thus adjusted magnetic encoder shown in the drawings will be described below.

The magnetic head (6') of the magnetic sensor A (6) cooperates with the magnetic track (2') of the first magnetic disk (2) to generate an electrical signal of 10 pulses per revolution of the shaft (l). do.

The magnetic head (6') cooperates with the magnetic track (2') to generate one electrical pulse per revolution of the shaft (1), producing a reference point signal for the shaft (1).

These signals are shown in Figure 4.

The rotation of the shaft (1) is decelerated to H and transmitted to the second magnetic disk (12) of the first unit (19), and the three magnetic tracks (12') (12'') of the magnetic disk (12) are
) (12') and the three magnetic heads (15') (15'') (15') of the magnetic sensor (15), the rotational position of the magnetic disc (12) is changed to 7 rotations as an absolute value. Similarly, each magnetic disk in the second, third, and fourth units (19', ) (19') (19//) is driven by the previous unit at a rotation speed reduced to 4. position detection is performed with a resolution of three rotations. Therefore, for one rotation of the shaft (1), the first unit (19) to the fourth unit (19')
Since the rotation is lowered to H for each unit, it is possible to detect the absolute value of 4096 rotations of the shaft (1).
Furthermore, since the first magnetic disk (2) fixed to the shaft (1) can generate a signal of 10 pulses and a reference point signal per revolution of the shaft, a high resolution of 40,960 pixels can be achieved.

Effects of the invention By increasing the number of stacked units, it is possible to easily change the resolution, and the magnetic disk of each unit requires only three magnetic tracks, making it possible to achieve a compact and easily adjustable height. An absolute type magnetic rotary encoder with high resolution can be provided at low cost. In addition, since the resolution can be changed simply by changing the number of stacked units, it is easy to meet the different resolution requirements of each customer.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic diagram showing a longitudinal section, FIG. 2 is a front view of the first magnetic disk, and FIG. 3 is a side view showing the arrangement of the first magnetic disk and magnetic sensor A. Figure 4 is a diagram explaining the signal of magnetic sensor A, Figures 5 (A) and (B) are diagrams explaining the front of the second magnetic disk and its magnetic trunk pattern, and Figure 6. 7 is a side view showing the arrangement of the second magnetic disk and the magnetic sensor, FIG. 7 is a diagram explaining the signal of the magnetic sensor B, and FIG. 8 is a side view showing the arrangement of the magnetic trunk of the second magnetic disk and the magnetic head. The front view and Figure 9 for explanation are of the magnetic sensor (
15) is a diagram illustrating the adjustment procedure of item 15), and shows the magnetic track developed in a straight line. (To)...Second large gear (11) constituting the gear train...
Second small gear (12) that constitutes the gear train...Second magnetic disk (12') (12'') (12//)...
Magnetic track (14)...Second body (15)...Magnetic sensor B

Claims (1)

[Claims] A magnetic disk that is fixed to the shaft and has a magnetic track for detecting absolute values with a resolution of 1/8, a magnetic sensor B placed close to this magnetic disk, a reduction gear train, these magnetic disks, and the magnetic sensor. A unit consisting of a body that supports B and a gear train is stacked, and the reduction ratio of the reduction gear train is determined so that the rotation ratio between the magnetic disks of adjacent units is 1/8. Magnetic rotary encoder.