JP2010032290A - Encoder which having bearing slide mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To move a bearing unit in which a hollow shaft having a code disk is integrated with a bearing unit in an axial direction to a base and adjust a gap between a light-receiving element and the code disk. <P>SOLUTION: In an encoder having a bearing slide mechanism, the bearing unit (20) comprising: the code disk (5); the hollow shaft (4); and the bering (2) is provided in such a way as to move in the axial direction to the base (1), and the gap (G) between the light-receiving element (28) provided for a printed wiring board (7) and the code disk (5) is made adjustable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an encoder having a bearing slide mechanism, and in particular, a bearing unit in which a hollow shaft having a code plate and a bearing are integrated is movable in an axial direction with respect to a base, and a gap between a light receiving element and a code plate The present invention relates to a new improvement for making the adjustment possible.

  Conventionally used encoders of this type include, for example, configurations shown in Patent Documents 1 to 4, but none of them is shown, but the base and the bearing are strongly fitted. Are joined together.

JP-A-8-204572 JP 62-278408 A US Pat. No. 5,912,541 Japanese Patent Laid-Open No. 9-105643

Since the conventional encoder is configured as described above, the following problems exist.
In other words, since the hollow shaft is fixed to the bearing and the bearing is fixed to the base, the gap between the light receiving element and the code plate cannot be adjusted after assembly. The gap between the code plate and the code plate may vary slightly, and it is difficult to improve yield and quality.
In addition, the gap between the code plate and the light receiving element is managed by the processing accuracy of surface grinding, but the processing accuracy varies.

  An encoder having a bearing slide mechanism according to the present invention includes a bearing unit including a hollow shaft having a sign plate fixed to one end and a pair of bearings fitted to the outer periphery of the hollow shaft, and an insertion for fitting the bearing unit. A base having a hole; a light emitting element provided on the base; a printed circuit board provided on one end surface side of the base with a light receiving element on an inner surface; and the printed circuit board provided on an outer peripheral surface of the base. A cup-shaped cover member for covering the gap, and the bearing unit is movable in the axial direction within the insertion hole, whereby the gap between the code plate and the light receiving element is adjustable. And the base and the bearing unit are fixed with an adhesive, and the base and the bearing unit are configured such that a screw passing through a screw hole on a side portion of the base is the Bearing unit And a flange portion extending toward the hole center of the insertion hole is formed on the other end surface of the base. The flange portion serves as a stopper for axial movement of the bearing unit in the insertion hole, and the lead wire connected to the printed circuit board is tangential to the outer diameter of the cup-shaped cover member. The base is made of resin, and the bearing unit is made of metal.

Since the encoder having the bearing slide mechanism according to the present invention is configured as described above, the following effects can be obtained.
That is, a bearing unit comprising a hollow shaft with a code plate fixed at one end and a pair of bearings fitted to the outer periphery of the hollow shaft, a base having a fitting hole for fitting the bearing unit, and the base A light-emitting element provided on the base, a printed circuit board having a light-receiving element on the inner surface provided on one end surface side of the base, and a cup-shaped cover member provided on the outer peripheral surface of the base for covering the printed circuit board The bearing unit is movable along the axial direction in the insertion hole, and the gap between the code plate and the light receiving element is adjustable, so that the bearing unit can be adjusted even after assembly. It can move in the axial direction, and yield and quality can be improved. Further, the surface grinding step can be omitted.
The base and the bearing unit are fixed with an adhesive, so that the bearing unit can be fixed after adjusting the gap between the light receiving element and the code plate.
Further, the base and the bearing unit are fixed by a screw passing through a screw hole in a side portion of the base being in contact with the unit outer peripheral surface of the bearing unit. The same effect as when using the agent can be obtained.
Further, a flange portion extending toward the hole center of the insertion hole is formed on the other end surface of the base, and the flange portion is a stopper for axial movement of the bearing unit in the insertion hole. As a result, it is possible to limit the position of the bearing unit during movement.
Further, the lead wire connected to the printed circuit board is drawn out along the tangential direction of the outer diameter of the cup-shaped cover member, thereby reducing the space when the lead wire of the encoder is led out to the outside, Encoder installation space can be minimized.
In addition, since the base is made of resin and the bearing unit is made of metal, it is possible to prevent electrical corrosion due to the metal of the bearing and to improve reliability.

  The present invention has a bearing slide mechanism in which a bearing unit in which a hollow shaft having a code plate and a bearing are integrated can be moved in the axial direction with respect to a base, and a gap between the light receiving element and the code plate can be adjusted. An object is to provide an encoder.

A preferred embodiment of an encoder having a bearing slide mechanism according to the present invention will be described below with reference to the drawings.
In addition, the same code | symbol is attached | subjected and demonstrated to a part the same as that of a prior art example, or an equivalent part.
In FIG. 1, reference numeral 1 denotes a base of an encoder, and a bearing unit 20 according to the present invention is fitted in the fitting hole 3 of the base 1 so as to be movable along the axial direction A. .

As shown in FIG. 2, the bearing unit 20 includes a pair of bearings fitted to the hollow shaft 4, a code plate 5 provided at one end 4 a of the hollow shaft 4, and an outer periphery 4 b of the hollow shaft 4. 2 and a bearing holding cylinder 21 provided on the outer periphery of each bearing 2.
Each of the bearings 2 and the hollow shaft 4 are integrally connected by a fastening nut 22 screwed to the outer periphery 4b of the hollow shaft 4 coming into contact with the bearing 2.

  A light emitting element 24 made of LED is provided in a recess 23 formed in a part of the base 1, and a pin 25 is implanted and provided at a position adjacent to the recess 23. The other portion 7b of the printed circuit board 7 in which a part 7a is inserted and supported by a boss 26a formed on one end face 26 of the 1 is connected to the pin 25, whereby the annular printed circuit board 7 is connected to the code plate 5. Is fixedly disposed with a predetermined distance D maintained. Since the printed circuit board 7 is positioned on the base 1 by the boss 26a, the printed circuit board 7 can be attached very easily and reliably.

  A light receiving element 28 is provided on the inner surface 27 of the printed circuit board 7 so as to face the light emitting element 24 and the code plate 5, and light from the light emitting element 24 passes through the code plate 5. Then, the light receiving element 28 receives the light and the code signal of the code plate 5 is read.

  The light receiving element 28 and the code plate 5 are opposed to each other in a state of being very close to each other, and the light passing through the code plate 5 is received by the light receiving element 28 without leaking to the periphery as much as possible. Thus, an encoder signal having a good S / N ratio can be obtained without causing such problems.

  The bearing unit 20 is configured so that the unit outer peripheral surface 30 can move in the insertion hole 3 along the axial direction A. Therefore, by moving the bearing unit 20 in the direction of the arrow A, the light receiving unit 20 is moved. A slight gap G between the element 28 and the code plate 5 can be finely adjusted. After the fine adjustment, the bearing unit 20 is inserted into the insertion hole of the base 1 by injecting an adhesive 35 between the insertion hole 3 and the bearing unit 20 or by applying the adhesive 35 to the outer periphery of the bearing holding cylinder 21 in advance. 3 is fixed.

  A flange portion 33 extending toward the hole center 32 of the insertion hole 3 is formed on the other end surface 31 side of the base 1, and the flange portion 33 is formed in the bearing unit 20 in the insertion hole 3. It is comprised so that it may become the stopper 34 of the axial direction movement.

  A cup-shaped cover member 6 having a cap shape as a whole is provided on the outer peripheral surface 1a of the base 1 so that the printed circuit board 7 and the code plate 5 are covered.

  As another form, the fixing method after fine adjustment of the base 1 and the bearing unit 20 is not limited to the method using the adhesive 35 described above. For example, as shown in FIG. A screw hole 41 formed in the side portion 40 and extending in the radial direction communicates with the fitting hole 3, and a tip of a screw 42 screwed into and penetrated into the screw hole 41 is a unit outer peripheral surface of the bearing unit 20. The bearing unit 20 is fixed to the base 1 by coming into contact with 30.

  Since the lead wire 8 connected to the printed circuit board 7 is drawn out along the tangential direction 8a of the outer diameter 6a of the cup-shaped cover member 6, there is a space for drawing out the lead wire 8 in plan view. This is a little less than before.

The base 1 can be formed of a metal such as aluminum. However, when the base 1 is formed of a resin and the bearing unit 20 is formed of a metal, deterioration of each bearing 2 due to electrolytic corrosion is caused. Can be prevented.
As another form of FIG. 3, as shown in FIG. 4, a substrate pressing claw 50 that extends a part of the base 1 in the direction of the code plate 5 is formed. The printed circuit board 7 can be locked and positioned.

It is sectional drawing which shows the encoder which has a bearing slide mechanism by this invention. It is sectional drawing which shows the principal part of FIG. It is a semi-sectional view which shows the other form of the principal part of FIG. It is a top view of FIG. It is sectional drawing which shows a conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 1a Outer peripheral surface 2 Bearing 3 Insertion hole A Axial direction 4 Hollow shaft 4b Outer periphery 5 Code plate 6 Cup-shaped cover member 6a Outer diameter 7 Printed circuit board 7a Part 7b Other part 8 Lead wire 8a Tangential direction 20 Bearing unit 21 Bearing Holding cylinder 23 Recess 24 Light emitting element 25 Pin 26 One end face 26a Boss 27 Inner face 28 Light receiving element 30 Unit outer peripheral face 31 Other end face 32 Hole center 33 Flange (stopper 34)
40 Side 41 Screw hole 42 Screw 50 Substrate pressing claw

Claims (6)

A bearing unit (20) comprising a hollow shaft (4) having a sign plate (5) fixed to one end (4a), and a pair of bearings (2) fitted to the outer periphery of the hollow shaft (4); A base (1) having a fitting hole (3) for fitting the bearing unit (20), a light emitting element (24) provided in the base (1), and one end surface of the base (1) A printed circuit board (7) having a light receiving element (28) on the inner surface (27) provided on the (26) side, and an outer peripheral surface (1a) of the base (1) to cover the printed circuit board (7) A cup-shaped cover member (6),
Since the bearing unit (20) is movable along the axial direction (A) in the insertion hole (3), the gap (G) between the code plate (5) and the light receiving element (28) is adjusted. An encoder having a bearing slide mechanism characterized by being free.   The encoder having a bearing slide mechanism according to claim 1, wherein the base (1) and the bearing unit (20) are fixed by an adhesive (35).   The base (1) and the bearing unit (20) include a screw (42) penetrating a screw hole (41) in a side portion (40) of the base (1), and a unit outer peripheral surface (30 The encoder having a bearing slide mechanism according to claim 1, wherein the encoder is fixed by being in contact with the encoder.   A flange portion (33) extending toward the hole center (32) of the insertion hole (3) is formed on the other end surface (31) of the base (1), and the flange portion (33 The encoder having a bearing slide mechanism according to any one of claims 1 to 3, wherein the encoder is a stopper (34) for axial movement of the bearing unit (20) in the fitting hole (3).   The lead wire (8) connected to the printed circuit board (7) is drawn out along a tangential direction (8a) of an outer diameter (6a) of the cup-shaped cover member (6). Item 5. An encoder having the bearing slide mechanism according to any one of Items 1 to 4.   The encoder having a bearing slide mechanism according to any one of claims 1 to 5, wherein the base (1) is made of resin, and the bearing unit (20) is made of metal.

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