JP5150831B2 - Encoder having a bearing slide mechanism - Google Patents

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.
That is, since the hollow shaft is fixed to the bearing and the bearing is fixed to the base, after assembly,
The gap between the light receiving element and the code plate cannot be adjusted, and the gap between the light receiving element and the code plate due to variations during assembly may vary slightly, making it difficult to improve yield and quality. It was.
Further, although the gap between the code plate and the light receiving element is managed by the processing accuracy of surface grinding, the processing accuracy varies.

From an encoder having a bearing slide mechanism according to the present invention includes a hollow shaft was directly solid boss at one end of the code plate, a bearing holding cylinder for holding the outer ring of the direct mated pair of bearings on the outer periphery of the hollow shaft a bearing unit comprising: a base having a fitting hole for the bearing unit input fitting through the unit outer peripheral surface of the bearing holding tube, a light emitting element provided on the base, one end surface of the base other portions partly fitted supported the formed boss and the PCB annular that having a light receiving element supported within the plane by a pin or substrate retaining pawl provided on the base, said base and a mosquito-up like cover member annular to provided on the outer circumferential surface covering the printed circuit board, the bearing unit axis in the bearing retaining cylinder periphery in the previous SL insertion hole through the unit outer peripheral surface consisting of It is possible to move along the direction. Accordingly, the gap between the code plate and the light receiving element Ri adjustable der, the the base end surface of is a flange portion extending formation toward the hole center of the insertion hole, the flange fastening parts are together with lying part and contactable at the lower end of the bearing holding tube, Ri Do the axial movement of the stopper of the bearing unit in the fitting hole, is screwed to the outer periphery of the hollow shaft The nut is in contact with the lower surface of only the inner ring of the bearing, the tapered hollow portion of the hollow shaft communicates with the opening of the cup-shaped cover member, and one end portion of the hollow shaft is opposite to the opening from the base. It is the structure which protrudes outside along the direction.

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, at least, a base having a bearing unit comprising a mated pair of bearings on the outer periphery of the hollow shaft and the hollow shaft with a fixed sign-plate on one end, a fitting hole for fitting the bearing unit A light emitting element provided on the base, a printed circuit board provided on one end surface side of the base and having a light receiving element on the inner surface, and a cup shape provided on the outer peripheral surface of the base for covering the printed circuit board A cover member, and the bearing unit is movable along the axial direction in the insertion hole, so that the gap between the code plate and the light receiving element is adjustable. The bearing unit can be moved in the axial direction, and yield and quality can be improved. Further, the surface grinding step can be omitted.
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.

  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. .

The bearing unit 20, as shown in FIG. 2, the hollow shaft 4, a code plate 5 kicked set directly to one end 4a of the hollow shaft 4, is fitted directly on the outer periphery 4b of the hollow shaft 4 a pair of bearings 2, to hold the outer ring 2b of the bearing 2, and a bearing holding cylinder 21. provided outside circumference.
Wherein by tightening nut 22 screwed on the outer periphery 4b of the hollow shaft 4 abuts against the lower surface 2aA only the inner ring 2a of bearing 2, and the bearing 2 and the hollow shaft 4 are coupled together form.

  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 board 7 is positioned on the base 1 by the boss 26a, the printed 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 along the axial direction A, the are fitted in the fitting hole 3 through the unit outer peripheral surface 30 of the bearing holding cylinder 21, so that the unit outer circumferential surface 30 in the previous SL insertion hole within 3 can move Therefore, by moving the bearing unit 20 in the direction of arrow A, the slight gap G between the light receiving 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 on the lower end 21 a of the holding cylinder 21. and it is configured such that the stopper 34 of the axial movement of the bearing unit 20 before Symbol fitting hole 3 as well as a portion contactable located.

Wherein the outer peripheral surface 1a of the base 1, the entire shape is provided mosquito-up like cover member 6 of the annular having an aperture 6A forms a cap-type, are configured such that the printed circuit board 7 and the code plate 5 is covered It is . The tapered hollow portion 4A of the hollow shaft 4 communicates with the opening 6A of the cup-shaped cover member 6, and one end portion 4B of the hollow shaft 4 protrudes from the base 1 to the outside along the direction opposite to the opening 6A. ing.

  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.

The lead wire 8 connected to the printed circuit board 7, because the in and pulled out along a tangential direction 8a of the front Symbol outer diameter 6a of the cup-shaped cover member 6 as shown in Figure 5, in plan view, leads The space for drawing out the wire 8 is slightly smaller 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 semi-sectional view which shows the other form of the principal part of FIG. It is a top view of FIG.

1 base 1a outer peripheral surface 2 bearing
2a inner ring
2b outer ring
2aA lower surface 3 insertion hole A axial direction 4 hollow shaft
4A tapered hollow
4B one end 4b outer periphery 5 code plate 6 cup-shaped cover member
6A opening 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 recessed part 24 light emitting element 25 pin 26 one end face 26a boss 27 inner face 28 light receiving element 30 unit outer face 31 others End face 32 Hole center 33 Flange (stopper 34)
40 Side 41 Screw hole 42 Screw 50 Substrate pressing claw

Claims (1)

Holding the code plate (5) directly solid boss was hollow shaft at one end (4a) to (4), the outer ring (2b) of a pair of bearings fitted directly on the outer periphery of the hollow shaft (4) (2) a bearing unit consisting of a bearing holding cylinder (21) for (20), said bearing unit (20) of the bearing holding cylinder (21) unit the outer peripheral surface (30) fitted through the inlet fitting for holes of ( 3), a light emitting element (24) provided on the base (1), and a boss (26a) formed on one end surface (26) of the base (1). part (7a) is fitted supported other part (7b) pin provided on the base (1) is (25) or light receiving element supported within the surface by the substrate holding claw (50) (27) (28) a print substrate (7) of the annular that Yusuke, annular mosquito-up like cover member for provided on the outer peripheral surface (1a) covering the printed circuit board (7) of the base (1) and (6) With
By the bearing unit (20) which is movable along the axial direction (A) in the previous SL insertion hole (3) in through the unit outer peripheral surface consisting of an outer periphery of the bearing holding cylinder (21) (30) the code plate (5) and the light receiving element (28) between the gap (G) is Ri adjustable der,
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 ) Is positioned so as to be able to contact a part of the lower end (21a) of the bearing holding cylinder (21), and the axial movement stopper (34) of the bearing unit (20) in the fitting hole (3). DOO-than, the hollow shaft (4) the outer periphery and the inner ring of the screwed a clamping nut (4b) (22) said bearing (2) (2a) the lower surface of only (2aA) contact of said hollow shaft The tapered hollow portion (4A) of (4) communicates with the opening (6A) of the cup-shaped cover member (6), and one end portion (4B) of the hollow shaft (4) is connected to the base (1) from the base (1). An encoder having a bearing slide mechanism that protrudes outward along a direction opposite to the opening (6A).

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