JP6312255B2 - Motor with encoder - Google Patents

Description

  The present invention relates to an encoder-equipped motor including an encoder that can accurately detect the rotational position and rotational speed of a motor shaft.

  For example, in the case of a motor used as a drive source for an industrial machine, it is necessary to detect the rotation angle of the motor shaft with high accuracy, and an optical encoder is often used as high-precision rotation angle detection means.

  In this type of motor with an encoder, the encoder is usually disposed on the opposite side of the motor (on the opposite side to the load side for extracting the rotational output from the motor shaft), and the encoder cover is attached to cover the encoder. .

  By the way, when an encoder is used, it is necessary to take measures against the evaporated components of grease generated from the bearings arranged close to the encoder, in addition to protection against dust and the like entering the encoder portion from the outside. This is because when the oil evaporated from the bearing adheres to the encoder disk, the information reading accuracy of the encoder disk is lowered. It is known that this oil component is warmed and evaporated by the heat generated when the motor is driven, and is cooled by contact with an encoder disk or the like.

  The technique described in Patent Document 1 is known as a countermeasure against oil generated from this type of bearing. 12 is a cross-sectional view of the motor with an encoder described in Patent Document 1, and FIG. 13 is an enlarged view of a main part thereof.

  As shown in FIG. 12, the motor with encoder 501 includes a motor main body 502 and an encoder 503 arranged on the non-load side (left side in FIG. 12) of the motor main body 502.

  The motor main body 502 includes a motor shaft 510 in which both ends are rotatably supported by bearings 541 and 542 inside the motor casing 530, and the end wall 533 of the motor casing 530 on the side opposite to the load side in the axial direction is arranged. An anti-load side bearing 542 is disposed on the inner periphery. The encoder 600 is disposed on the side opposite to the load from the bearing 542, the encoder cover 570 is disposed so as to cover the encoder 600, and the encoder 600 is accommodated in the cover internal space 580.

  As shown in FIG. 13, the encoder 600 includes an encoder disk 610 fixed to the motor shaft 510 side and a reading-side reading optical unit 602 such as an LED or a photosensor. The encoder disk 610 is fixed to a hub 608 fitted and fixed to the end of the motor shaft 510 on the side opposite to the load, and the hub 608 positions the inner ring of the bearing 542 on the side opposite to the load via an adjustment shim 620. It is regulated. An annular wall that forms a labyrinth 650 with an annular flange 608 a provided on the outer periphery of the hub 608 is provided on the inner periphery of the end wall 533 on the side opposite to the load of the motor casing 530 that fixes the outer ring of the bearing 542. 533a is provided. The labyrinth 650 protects the oily gas generated on the bearing 542 side from entering the encoder 600 side.

Japanese Patent No. 5304464

  By the way, in the case of the motor 501 with an encoder shown in FIG. 12 and FIG. 13 described in Patent Document 1, one side in the thrust direction of the outer ring of the bearing 542 is an annular on the counterload side provided on the end wall 533 of the motor casing 530. Since the position is only restricted in the axial direction by the wall 533a, the bearing 542 may move to the load side when the load force is applied to the motor shaft 510. In order to prevent the bearing 542 from moving in this manner, it is conceivable to press-fit the outer ring of the bearing 542 into the inner periphery of the through hole of the end wall 533 of the motor casing 530. When the inner ring of the bearing 542 is press-fitted and fitted to the outer periphery of 510, the inner ring and the outer ring are both press-fitted and fitted, and an excessive radial load is always applied to the bearing 542, which may shorten the bearing life. Become.

  Further, in the case of the motor 501 with an encoder, the labyrinth 650 is configured by the annular wall 533a formed directly on the end wall 533 of the motor casing 530, so that it is difficult to manage the dimensions with the counterpart annular flange 608a. For this reason, there was a possibility that a large gap between the labyrinth 650 had to be taken. In addition, since the shim 620 for adjusting the position of the encoder disk 610 automatically adjusts the gap of the labyrinth 620, the labyrinth cannot be adjusted independently, and it is difficult to have an optimal labyrinth effect. .

  The present invention has been made in view of the above-described circumstances, and can exhibit a high labyrinth effect and efficiently capture oily gas generated in the bearing, so that an excessive radial load does not act on the bearing. An object of the present invention is to provide a highly reliable motor with an encoder that can extend the life of the bearing.

  In order to solve the above-described problems, the motor with an encoder according to the present invention is a motor with an encoder provided with an encoder that detects a rotation angle of a motor shaft on one end side in the axial direction of the motor casing. A cylindrical wall through which the motor shaft is inserted on the inner peripheral side, an outer ring is fitted to the inner circumferential surface of the cylindrical wall, and an inner ring is fitted to the outer circumferential surface of the motor shaft, A rolling bearing that rotatably supports the motor shaft with respect to the motor casing, and is provided on one end side in the axial direction of the motor shaft so as to rotate integrally with the motor shaft; A hub portion constituting an encoder, and press-fitted between the rolling bearing and the hub portion on the outer peripheral surface of the motor shaft; The inner ring of the rolling bearing is regulated in position in the axial direction, and the spacer ring for positioning the hub portion in the axial direction corresponds to the other end in the axial direction of the rolling bearing on the inner peripheral surface of the cylindrical wall. A stopper wall provided at a position, and press-fitted into a position corresponding to one end in the axial direction of the rolling bearing on the inner peripheral surface of the cylindrical wall, and in cooperation with the stopper wall, the outer ring of the rolling bearing is A bearing fixing ring that regulates the position in a direction, and a labyrinth that captures an oily gas entering from the rolling bearing toward the encoder is provided between opposing surfaces of the spacer ring and the bearing fixing ring. It is characterized by that.

  By comprising in this way, when an airflow passes through the labyrinth formed by the spacer ring and the bearing fixing ring, it is possible to effectively capture the oily gas generated from the rolling bearing. In other words, the presence of the labyrinth increases the distance until the oily gas enters the encoder side and increases the pressure loss, making it difficult for the air to flow. For this reason, it is difficult for oily components to reach the encoder, and the occurrence probability of the malfunction of the encoder can be suppressed.

  Further, since the position of the outer ring of the rolling bearing is restricted to both sides in the axial direction by the bearing fixing ring and the stopper wall, it is not necessary to press fit into the cylindrical wall of the motor casing. In other words, even when the inner ring is press-fitted to the motor shaft, the outer ring does not need to be press-fitted to the motor housing, so the radial load generated when both the inner ring and outer ring are press-fitted can be reduced. Can contribute to longer life. Therefore, coupled with the labyrinth effect, it is possible to realize a highly reliable motor with an encoder.

  Furthermore, the labyrinth is formed between two parts: a spacer ring press-fitted to the outer periphery of the motor shaft, and a bearing fixing ring press-fitted as a separate part to the cylindrical wall of the motor casing. No extra dimension adjusting member such as a shim is required, and the labyrinth dimension can be set with high accuracy. Thereby, it becomes possible to set the gap of the labyrinth small, and it is possible to enhance the oil capturing effect.

  The motor with an encoder according to the present invention is characterized in that the spacer ring and the bearing fixing ring are made of metal.

  With this configuration, when passing through the labyrinth, the oily gas is cooled and easily condensed due to contact with the surface of the metal spacer ring or bearing fixing ring. For example, when air contacts the rotating flange portion, the air receives a force in the rotation direction by the flange portion. Therefore, the air flow is complicated by the air subjected to the rotational force, and the opportunity for the air to come into contact with the surrounding walls is increased, and the condensation of the oily gas is promoted. As a result, it is difficult for oily components to reach the encoder, and the occurrence probability of the malfunction of the encoder can be suppressed.

  In the motor with an encoder according to the present invention, the spacer ring is formed on one end side in the axial direction with respect to the ring main body that is press-fitted into the outer peripheral surface of the motor shaft, and the bearing fixing ring in the ring main body. An annular body having an L-shaped cross section having an outwardly extending flange portion, and the outer peripheral surface of the ring main body is configured as a first labyrinth forming surface parallel to the inner peripheral surface of the ring main body, An end surface of the ring main body that contacts the inner ring of the rolling bearing is configured as a spacer position regulating surface orthogonal to the outer peripheral surface and the inner peripheral surface of the ring main body, and the side surface of the flange portion on the bearing fixing ring side is the spacer The bearing fixing ring is configured as a second labyrinth forming surface parallel to the position regulating surface. On the other hand, the bearing fixing ring is an annular body having a rectangular cross section. The surface is configured as a first labyrinth forming surface parallel to the outer peripheral surface of the bearing fixing ring, and the end surface of the bearing fixing ring that contacts the outer ring of the rolling bearing includes the inner peripheral surface and the outer peripheral surface of the bearing fixing ring. The end surface on one end side in the axial direction of the bearing fixing ring is configured as a second labyrinth forming surface parallel to the fixing ring position restricting surface, and the spacer ring The first labyrinth forming surface and the first labyrinth forming surface of the bearing fixing ring are opposed to each other in parallel with a small radial distance therebetween, thereby forming a first narrow flow path therebetween. The second labyrinth forming surface of the spacer ring and the second labyrinth forming surface of the bearing fixing ring face each other in parallel with a small gap in the axial direction. A second narrow flow path is formed between them, and the first narrow flow path and the second narrow flow path form a continuous narrow flow path that is bent at a right angle. Thus, the labyrinth is formed.

By configuring in this way, the first labyrinth forming surface in the radial direction of the spacer ring and the first labyrinth forming surface in the radial direction of the bearing fixing ring are respectively press-fit surfaces (ring main bodies) that are in parallel relation to each other. The outer peripheral surface of the bearing and the outer peripheral surface of the bearing fixing ring) can be accurately coaxially processed.
In addition, each end surface (spacer position regulating surface and fixing ring) that abuts the second labyrinth forming surface in the axial direction of the spacer ring and the second labyrinth forming surface in the axial direction of the bearing fixing ring on the side surface of the same rolling bearing, respectively. Processing can be performed with high accuracy with reference to the position regulating surface.
Therefore, the first narrow flow path formed between the first labyrinth forming surface of the spacer ring and the first labyrinth forming surface of the bearing fixing ring can be ensured with high accuracy, and the second of the spacer ring can be secured. The second narrow flow path formed between the labyrinth forming surface and the second labyrinth forming surface of the bearing fixing ring can be ensured with high accuracy. As a result, the dimension of the labyrinth can be ensured with high accuracy without performing special shim adjustment, and a high labyrinth effect can be exhibited by setting the labyrinth gap small.

  The motor with an encoder according to the present invention is characterized in that irregularities for increasing the surface area are formed on the surface of the flange portion of the spacer ring.

  By comprising in this way, the oily gas which contacts a flange part can be cooled and it can be made to condense effectively. Further, by cooling the flange portion, the rolling bearing is cooled by heat conduction, and the evaporation of the grease oil is reduced. As a result, it is possible to suppress oily components that try to enter the encoder side.

  The motor with an encoder according to the present invention is characterized in that a concave portion is formed on the surface of the flange portion of the spacer ring in a direction to reduce the thickness of the flange portion.

  By comprising in this way, since the thermal mass of a flange part reduces and thermal resistance becomes large, the heat conduction from the motor shaft side becomes small. Therefore, the temperature of the flange portion having a large diameter is lower than that of the motor shaft. As a result, the effect of contributing to cooling of the scattered grease oil is increased, and the oil gas trapping rate is increased.

  In the motor with an encoder according to the present invention, eddy current generating means for generating an eddy current by rotation of the flange portion in the air flow passing through or after passing the labyrinth is provided at or near the flange portion of the spacer ring. It is characterized by being.

  By comprising in this way, the opportunity for an airflow to contact the surrounding wall can be increased, and oily gas can be cooled and condensed effectively.

  In the motor with an encoder according to the present invention, at least one of the ring main body and the flange portion of the spacer ring is formed on a surface forming the labyrinth, and a condensed component of oily gas during or after passing the labyrinth. An oil sump for collecting the water is provided.

  By comprising in this way, the movement of an oil component can be restrict | limited and the penetration rate to the encoder side can be reduced.

  The motor with an encoder according to the present invention is characterized in that a thickness increasing portion having a thickness increased from an inner peripheral side of the flange portion is provided at an outer peripheral end portion of the flange portion of the spacer ring.

  By comprising in this way, even if the thermal mass of a flange part becomes large and there exists heat conduction from the motor shaft side, the temperature rise of a flange part can be suppressed. Therefore, the cooling effect of the grease oil can be enhanced.

  ADVANTAGE OF THE INVENTION According to this invention, the high labyrinth effect can be exhibited and the oil-based gas generated with a bearing can be captured efficiently. Further, it is possible to prevent an excessive radial load from acting on the bearing, thereby extending the bearing life. As a result, high reliability can be obtained.

It is a whole sectional view of a motor with an encoder in a 1st embodiment of the present invention. It is a partial expanded sectional view of the motor with an encoder in a 1st embodiment of the present invention. It is a partial expanded sectional view of the motor with an encoder in a 1st embodiment of the present invention. It is a partial expanded sectional view of the motor with an encoder in a 1st embodiment of the present invention. It is a partial expanded sectional view of the motor with an encoder in 2nd Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 3rd Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 4th Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 5th Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 6th Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 7th Embodiment of this invention. It is a partial expanded sectional view of the motor with an encoder in 8th Embodiment of this invention. It is whole sectional drawing of the motor with an encoder shown as a prior art example. It is a partial expanded sectional view of the motor with an encoder shown as a prior art example.

Hereinafter, a motor with an encoder according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a motor with an encoder in the embodiment, and FIGS. 2 to 4 are partial enlarged views of FIG.

  As shown in FIG. 1, the motor 1 with an encoder includes a motor main body 2 and an encoder 3 arranged outside the motor main body 2 on the side opposite to the load (upper side in FIG. 1).

(Motor body)
The motor body 2 is configured as a brushless motor in which a hollow motor shaft 30 having a rotor magnet 18 mounted on the outer periphery thereof is rotatably passed through a hollow annular motor casing 30 having a stator 34 therein.
Of the axial ends of the motor shaft 10 protruding from both ends of the motor casing 30, one end side (lower side in FIG. 1) is the load side and the other end side (upper side in FIG. 1) is the anti-load side. To do.

  The motor casing 30 includes a load-side main housing 31 and a side housing (an axially anti-load-side end wall) 33 connected so as to close the opening at the opposite end of the cylindrical wall of the main housing 31. . The motor shaft 10 that passes through the motor casing 30 is rotatably supported by two rolling bearings 41 and 42 that are fitted to the inner circumferences of the through holes 31e and 33e in the radial center of the main housing 31 and the side housing 33. ing.

The side housing 33 on the side opposite to the load is provided with an outer peripheral cylindrical wall 33 a coupled to the end on the side opposite to the load of the main housing 31. A disc wall 33b extending perpendicularly inward in the radial direction is connected to the end of the outer cylindrical wall 33a on the side opposite to the load. An inner peripheral cylindrical wall 33c extending to the load side in parallel with the axial direction is connected to the inner peripheral end of the disc wall 33b. A stopper wall 33d that is bent vertically inward in the radial direction is connected to the end portion on the load side of the inner peripheral cylindrical wall 33c.
The through hole 33e into which the anti-load-side rolling bearing 42 is fitted is formed as a space inside the inner peripheral cylindrical wall 33c, and the inner peripheral cylindrical wall 33c is formed as a peripheral wall of the through hole 33e.

  A stator 34 housed in the motor casing 30 includes a stator core 35 fitted to the inner periphery of the cylindrical wall of the main housing 31, a coil 37 wound around each tooth of the stator core 35 via an insulator 36, and Consists of. The ring magnet as the rotor magnet 18 is held at a position corresponding to each tooth on the outer periphery of the motor shaft 10. The motor body 2 configured as described above can rotate the motor shaft 10 relative to the motor casing 30 by energizing the coil 37 of the stator 34.

(bearing)
The load-side rolling bearing 41 is regulated in the axial direction by being sandwiched between the outer ring of the motor shaft 10 and the spacer ring 20 fitted adjacent to the rotor magnet 18. As shown in FIG. 2, the anti-load-side rolling bearing 42 includes an inner ring 42a, an outer ring 42b, and rolling elements (balls) 42c sandwiched between the inner ring 42a and the outer ring 42b. Grease for lubrication is injected into the rolling bearing 42.

  The inner ring 42a is in a state of being press-fitted and fitted to the outer periphery of the motor shaft 10, and a fixed ring 44 fitted to the outer periphery of the motor shaft 10 and a load side of the spacer ring 20 press-fitted to the outer circumference of the motor shaft 10. The position is regulated in the axial direction by being sandwiched between the two end surfaces. The outer ring 42b includes a bearing stopper wall 33d projecting from the inner periphery of the inner peripheral cylindrical wall 33c of the side housing 33 of the motor casing 30, and a bearing fixing press fitted to the inner periphery of the inner peripheral cylindrical wall 33c. By being sandwiched between the ring 38, the position is restricted in the axial direction.

  The end of the motor shaft 10 on the side opposite to the load is inserted into the encoder unit 3. The encoder unit 3 is provided with an encoder 100, a circuit board 50 for controlling the motor main body unit 2, and an encoder cover 70 fixed to the side housing 33 of the motor casing 30 with bolts so as to cover them. . The circuit board 50 is for giving a control signal to the coil 37 of the stator 34, and is bolted to the side housing 33.

(Encoder)
As shown in FIGS. 1 and 2, the encoder 100 is an optical encoder for detecting the rotation angle of the hollow shaft 10.
The encoder 100 includes an encoder disk member 110 attached to the outer periphery of the hollow shaft 10. The encoder disk member 110 has a cylindrical hub portion 111 fitted on the outer periphery of the small diameter portion 12 of the hollow shaft 10 via a spline 112. A disc body 113 is integrally formed on the outer peripheral surface of the hub 111.

The disk main body 113 is provided as an annular thin portion on the outer peripheral side of the thick disc portion 115 provided perpendicular to the cylindrical hub portion 111. A surface on the load side of the disk main body 113, that is, a surface facing the circuit board 50 in the axial direction is a code forming surface 114.
On the circuit board 50, a code reading optical element (optical reading means) 102 having a light emitting means and a light receiving means is mounted on a surface facing the disk main body 113 and at a position corresponding to the code forming surface 114. ing.

(Encoder cover)
The encoder cover 70 is an annular cup type cover member in which the peripheral edge of the opening in the center in the radial direction is opposed to the end portion on the non-load side of the motor shaft 10 with a minute gap. The encoder cover 70 is fixed to the motor casing 30 to cover the cover internal space 80 that houses the encoder 100 from the outside.

  A fixing flange 71 for fixing to the side housing 33 is provided on the outer periphery of the encoder cover 70. A conical cup wall 72 swelled on the anti-load side is connected to the inner peripheral side of the fixed flange 71. A side wall 73 perpendicular to the axial direction is provided on the inner peripheral side of the cup wall 72, and a sleeve cylinder portion 74 extending in parallel along the axial direction is continuously provided at the radial center of the side wall 73. . This sleeve cylinder portion 74 extends toward the load side as a peripheral wall of the opening in the center in the radial direction, and the inner peripheral surface on the tip side is minute on the outer peripheral surface of the end portion on the non-load side of the motor shaft 10. Opposing in the radial direction with a gap.

(Spacer ring)
The spacer ring 20 is press-fitted to the outer periphery of the motor shaft 10 between the hub portion 111 of the encoder disk member 110 and the inner ring 42 a of the rolling bearing 42. The spacer ring 20 functions to position the inner ring 42a of the rolling bearing 42 in the axial direction and position the encoder disk member 110 in the axial direction.
As shown in FIG. 3, the spacer ring 20 includes a ring main body 21 that is press-fitted to the outer periphery of the motor shaft 10, and a flange that is formed on the non-load side of the ring main body 21 and extends radially outward. And an L-shaped annular body having a portion 22.

  The outer peripheral surface of the ring main body 21 of the spacer ring 20 is a first labyrinth forming surface 21 a parallel to the press-fit fitting surface 20 a of the spacer ring 20 with respect to the motor shaft 10 on the inner periphery of the ring main body 21. Further, the end surface 21b on the load side of the ring main body 21 of the spacer ring 20 that abuts on the side opposite to the load side of the inner ring 42a of the rolling bearing 42 is a spacer position restricting surface orthogonal to the press-fitting fitting surface 20a. The spacer position restricting surface is a surface in which the position of the spacer ring 20 in the axial direction is restricted by contacting the side surface of the inner ring 42a of the rolling bearing 42.

  Further, of the opposite side surfaces 22 a and 22 b on the opposite side and the load side of the flange portion 22 of the spacer ring 20, the side surface 22 b on the load side is parallel to the end surface 21 b on the load side of the ring body 21. 2 labyrinth forming surface 22b (also referred to as load side surface 22b). The spacer ring 20 is made of a metal material having good thermal conductivity (for example, aluminum or aluminum alloy).

(Bearing fixing ring)
On the other hand, the bearing fixing ring 38 is press-fitted and fitted to the inner periphery on the side opposite to the axial direction from the rolling bearing 42 of the inner peripheral cylindrical wall 33 c of the side housing 33. The bearing fixing ring 38 serves to restrict the position of the outer ring 42b in the axial direction by sandwiching the outer ring 42b of the rolling bearing 42 with the stopper wall 33d protruding from the inner periphery of the inner peripheral cylindrical wall 33c. Plays. In other words, the bearing fixing ring 38 regulates the axial position of the outer ring 42b of the rolling bearing 42 in cooperation with the stopper wall 33d.

The bearing fixing ring 38 is an annular body having a rectangular cross section disposed on the outer peripheral side of the ring main body 21 of the spacer ring 20 and on the load side of the flange portion 22. The inner peripheral surface of the bearing fixing ring 38 is a first labyrinth forming surface 38b parallel to the press-fit fitting surface 38a of the bearing fixing ring 38 with respect to the inner periphery of the inner peripheral cylindrical wall 33c.
Furthermore, the end surface 38c on the load side of the bearing fixing ring 38 that contacts the side surface of the outer ring 42b of the rolling bearing 42 is a fixing ring position regulating surface orthogonal to the press-fitting fitting surface 38a. The fixed ring position restricting surface is a surface in which the axial position of the bearing fixing ring 38 is restricted by contacting the side surface of the outer ring 42b of the rolling bearing 42.

  Further, the end surface on the opposite side of the bearing fixing ring 38 is a second labyrinth forming surface 38d parallel to the end surface 38c on the load side. The bearing fixing ring 38 and the side housing 33 into which the bearing fixing ring 38 is press-fitted are also made of a metal material having good thermal conductivity (for example, aluminum or aluminum alloy).

  The first labyrinth forming surface 21a of the spacer ring 20 and the first labyrinth forming surface 38b of the bearing fixing ring 38 are opposed to each other in parallel with a small radial distance therebetween. A narrow channel 201 is formed. Further, the second labyrinth forming surface 22b of the spacer ring 20 and the second labyrinth forming surface 38b of the bearing fixing ring 38 are opposed to each other in parallel with a small axial distance therebetween, so that the first Two narrow flow paths 202 are formed.

  Both the spacer ring 20 and the bearing fixing ring 38 that rotate relative to each other are made of metal, and capture the oily gas that is about to enter the encoder disk member 110 from the rolling bearing 42 between the opposing surfaces of both of them. A labyrinth 200 is provided. That is, the labyrinth 200 is formed by forming a continuous narrow channel in which the first narrow channel 201 and the second narrow channel 202 are bent at right angles.

(Function)
Next, the operation will be described.
Since the motor 1 with an encoder is configured as described above, the first labyrinth forming surface 21a in the radial direction of the spacer ring 20 and the first radial direction of the bearing fixing ring 38 are provided as shown in FIG. One labyrinth forming surface 38b can be coaxially processed with high accuracy on the basis of the press-fitting fitting surfaces 20a and 38a that are parallel to each other.
That is, the outer diameter D2 of the first labyrinth forming surface 21a of the spacer ring 20 can be coaxially processed with the inner diameter D1 of the press-fitting fitting surface 20a, so that it can be finished with high accuracy. Similarly, since the inner diameter D3 of the first labyrinth forming surface 38b of the bearing fixing ring 38 can be coaxially processed with the outer diameter D4 of the press-fitting fitting surface 38a, it can be finished with high accuracy.

  Further, the second labyrinth forming surface 22b of the spacer ring 20 and the second labyrinth forming surface 38d of the bearing fixing ring 38 have a dimension S1 with the end faces 21b and 38c contacting the side surfaces of the same rolling bearing 42 as the reference K. , S2 can be obtained, so that it can be processed with high accuracy.

  Therefore, the clearance H1 of the first narrow flow path 201 formed between the first labyrinth forming surface 21a of the spacer ring 20 and the first labyrinth forming surface 38b of the bearing fixing ring 38 is ensured with high accuracy. Can do. In addition, the gap H2 of the second narrow flow path 202 formed between the second labyrinth forming surface 22b of the spacer ring 20 and the second labyrinth forming surface 38d of the bearing fixing ring 38 is ensured with high accuracy. Can do. As a result, the dimension of the labyrinth 200 can be ensured with high accuracy without performing special shim adjustment, and a high labyrinth effect can be exhibited by setting the gap of the labyrinth 200 small.

  Since the labyrinth 200 is secured as described above, the oily gas generated from the rolling bearing 42 can be effectively captured when the air flow F passes through the labyrinth 200. That is, the presence of the labyrinth 200 increases the distance until the oily gas enters the encoder 100 and increases the pressure loss, making it difficult for air to flow.

  Further, when passing through the labyrinth 200, the oily gas is cooled and easily condensed by contacting the surfaces of the metal spacer ring 20 and the bearing fixing ring 38. For example, as shown in FIG. 4, when air contacts the rotating flange portion 22, the air receives a force in the rotation direction by the flange portion 22. For this reason, the air flow Y2 subjected to the rotational force collides with, for example, the upward flow Y1, so that the air flow becomes complicated, and the opportunity for the air to come into contact with the surrounding walls is increased and the condensation of the oily gas is promoted. Is done. As a result, it is difficult for oily gas to reach the encoder 100 side, and the probability of occurrence of problems in the encoder 100 such as oil adhering to the code forming surface 114 of the encoder disk member 110 and the optical element 102 can be suppressed.

  Further, since the outer ring 42b of the rolling bearing 42 is regulated in position in the axial direction by the bearing fixing ring 38 and the stopper wall 33d, it is necessary to press-fit into the inner peripheral cylindrical wall 33c of the side housing 33 of the motor casing 30. There is no. That is, even when the inner ring 42a is press-fitted to the motor shaft 10, there is no need to press-fit the outer ring 42b to the motor casing 30, so the inner ring 42a and the outer ring 42b shown by the arrow RK in FIG. The radial load from the housing side (motor casing 30 side) that occurs in the case of both of the press-fitting fittings can be eliminated (indicated by x in the figure). Therefore, it is possible to contribute to extending the life of the rolling bearing 42. Therefore, it is possible to realize a highly reliable motor 1 with an encoder by combining the labyrinth effect. In addition, when the thrust load which acts on the rolling bearing 42 from the motor shaft 10 side is shown by an arrow EA in FIG. 1, the reaction force and the frictional force EB are generated as opposed to the thrust load to support the thrust load.

  The labyrinth 200 is formed between two parts: a spacer ring 20 press-fitted to the outer periphery of the motor shaft 10 and a bearing fixing ring 38 press-fitted to the inner peripheral cylindrical wall 33c of the motor casing 30 as separate parts. Has been. For this reason, unlike the conventional example, an extra dimension adjusting member such as a shim for securing the dimension is unnecessary, and the labyrinth dimension can be set with high accuracy. Thereby, it becomes possible to set the clearance gap of the labyrinth 200 small, and can raise the capture effect of an oil component.

  As described above, according to the motor 1 with an encoder of the first embodiment, a high labyrinth effect can be exhibited and oily gas generated in the rolling bearing 42 can be efficiently captured. Further, it is possible to prevent an excessive radial load from acting on the rolling bearing 42 and to extend the bearing life. As a result, high reliability can be obtained.

Next, other embodiments will be described.
(Second Embodiment)
FIG. 5 is a partially enlarged cross-sectional view of a motor with an encoder in the second embodiment of the present invention.
As shown in FIG. 5, the flange portion 22 of the spacer ring 20 </ b> B of the second embodiment is provided with uneven fins 23 for increasing the surface area on the surface of the outer peripheral end. This is different from the first embodiment described above.

  Therefore, according to 2nd Embodiment, in addition to the effect similar to the above-mentioned 1st Embodiment, the heat dissipation of the flange part 22 can be improved. Therefore, the oily gas contacting the flange portion 22 can be cooled and condensed effectively. Moreover, by cooling the flange part 22, the rolling bearing 42 is cooled by heat conduction, and evaporation of grease oil is reduced. As a result, it is possible to suppress the oily component that tends to enter the encoder 100 side.

(Third embodiment)
FIG. 6 is a partially enlarged cross-sectional view of a motor with an encoder in the third embodiment of the present invention.
As shown in FIG. 6, the flange portion 22 of the spacer ring 20 </ b> C of the third embodiment is formed with a recess 24 in the direction in which the thickness of the flange portion 22 is reduced on the second labyrinth forming surface 22 b. This is different from the first embodiment described above.

  Therefore, according to the third embodiment, in addition to the same effects as those of the first embodiment described above, the thermal mass of the flange portion 22 can be reduced, and the thermal resistance can be increased. Therefore, the heat conduction from the motor shaft 10 side is reduced, and the flange portion 22 having a large diameter is lower in temperature than the motor shaft 10. As a result, the effect of contributing to the cooling of the scattered grease oil is increased, and the capture rate of the oily gas is increased.

(Fourth embodiment)
FIG. 7 is a partially enlarged sectional view of a motor with an encoder in the fourth embodiment of the present invention.
As shown in FIG. 7, the difference between the third embodiment and the fourth embodiment is that the spacer ring 20C of the third embodiment has a recess 24 formed on the second labyrinth forming surface 22b. In contrast, the spacer ring 20D of the fourth embodiment is provided with a recess 24 on the side surface 22a on the outer surface side of the flange portion 22.
Here, the ambient temperature on the outer side surface 22a side of the flange portion 22 is lower than the ambient temperature on the second labyrinth forming surface 22b side of the flange portion 22. For this reason, the heat dissipation effect of the flange portion 22 can be enhanced by providing the recess 24 on the outer side surface 22a of the flange portion 22.

(Fifth embodiment)
FIG. 8 is a partially enlarged cross-sectional view of a motor with an encoder in the fifth embodiment of the present invention.
As shown in FIG. 8, in the spacer ring 20E of the fifth embodiment, the vortex flow is generated in the flange portion 22 or in the vicinity thereof so that the vortex flow is generated by the rotation of the flange portion 22 in the air flow passing through or after passing through the labyrinth 200. Means are provided. This is different from the first embodiment described above.

  As the eddy current generating means, for example, a structure in which a spiral ridge 25 is provided on the end surface of the outer peripheral end 22c of the flange portion 22 can be employed. Further, it is also possible to adopt a structure in which a convex portion 26 is provided on the second labyrinth forming surface 22b of the spacer ring 20E, and the spacer ring 20E is inserted into a concave portion 33f formed on the disc wall 33b of the side housing 33E without contact. Also, a structure in which a through hole 33k is provided in the disk wall 33b of the side housing 33E can be employed to promote the air flow.

  Therefore, according to the above-described fifth embodiment, by providing the eddy current generating means (such as the spiral ridge 25, the convex portion 26, the concave portion 33f, or the through hole 33g), the air flow contacts the surrounding wall. Opportunities can be increased and oily gases can be cooled and condensed effectively.

(Sixth embodiment)
FIG. 9 is a partially enlarged cross-sectional view of a motor with an encoder according to a sixth embodiment of the present invention.
As shown in FIG. 9, the spacer ring 20 </ b> F of the sixth embodiment has a recess 27 a on the second labyrinth forming surface 22 b, and the outer peripheral end 22 c of the flange portion 22 extends radially inward from the load side. A hook-shaped portion 27b formed so as to be folded is provided. These points are different from the first embodiment described above.

And the oil sump 27c which followed the recessed part 27a is formed in the pocket part of the hook-shaped part 27b. By forming the oil reservoir 27c, the condensed component of the oily gas during or after passing through the labyrinth 200 can be collected by the oil reservoir 27c.
In addition, a recess 33g in which the hook-shaped portion 27c is accommodated in a non-contact manner is formed on the wall surface of the side housing 33F facing the hook-shaped portion 27c. By forming the recess 33g, resistance can be given to the flow of the oily gas passing through the labyrinth 200.

  Therefore, according to the above-described sixth embodiment, the movement of the oil component adhering to the flange portion 22 can be restricted, and the oil component can be reliably prevented from entering the encoder 100 side.

(Seventh embodiment)
FIG. 10 is a partially enlarged cross-sectional view of an encoder-equipped motor according to the seventh embodiment of the present invention.
As shown in FIG. 10, the spacer ring 20 </ b> G according to the seventh embodiment is provided with a thickness increasing portion 28 having a thickness increased from the inner peripheral side of the flange portion 22 at the outer peripheral end 22 c of the flange portion 22. Yes. Further, a recess 33h into which a part of the thickness increasing portion 28 enters in a non-contact manner is formed on the wall surface on the side housing 33G facing the thickness increasing portion 28 so as to provide resistance to the flow of the oily gas. It has become. These points are different from the first embodiment described above.

  Therefore, according to the seventh embodiment described above, the thermal mass of the flange portion 22 can be increased by the thickness increasing portion 28. For this reason, also when there exists heat conduction from the motor shaft 10 side, the temperature rise of the flange part 22 can be suppressed. Therefore, the cooling effect of the grease oil can be enhanced.

(Eighth embodiment)
FIG. 11 is a partially enlarged sectional view of a motor with an encoder according to an eighth embodiment of the present invention.
As shown in FIG. 11, the spacer ring 20 </ b> H of the eighth embodiment collects a condensed component of the oily gas during or after passing through the labyrinth 200 at the intersection between the flange portion 22 and the ring main body 21. An oil sump 29 is provided. This is different from the first embodiment described above.

  Therefore, according to the above-described eighth embodiment, by providing the oil reservoir 29, the movement of the oil component attached to the flange portion 22 can be limited. For this reason, it can prevent reliably that an oil component penetrate | invades into the encoder 100 side.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where an optical encoder is employed as the encoder 100 that detects the rotation angle of the motor shaft 10 has been described. However, the present invention is not limited to this, and a magnetic encoder may be employed. In this case, for example, a ring-shaped magnet may be disposed on the disk main body 113 of the encoder disk member 110, and a Hall element or the like for detecting a change in magnetism may be provided in place of the optical element 102.

  In the above-described embodiment, the case where a hollow shaft is employed as the motor shaft 10 has been described. However, the present invention is not limited to this, and a solid shaft may be adopted as the motor shaft 10 instead of the hollow shaft.

DESCRIPTION OF SYMBOLS 1 ... Motor with encoder 2 ... Motor main-body part 3 ... Encoder part 10 ... Motor shaft 20, 20B, 20C, 20D, 20E, 20F, 20G, 20H ... Spacer ring 20a ... Press fitting fitting surface 21 ... Ring main body 21a ... 1st Labyrinth forming surface 21b ... Load side end surface (spacer position regulating surface)
22 ... Flange 22b ... 2nd labyrinth forming surface 22c ... Outer peripheral edge 23 ... Concave fin 24 ... Concave 25 ... Spiral ridge (vortex generating means)
26 ... convex portion (vortex flow generating means)
27a ... concave portion 27b ... hook-shaped portion 27c ... oil reservoir 28 ... thickened portion 29 ... oil reservoir 30 ... motor casing 33, 33E, 33F, 33G ... side housing 33c ... inner peripheral cylindrical wall (cylindrical wall)
33d ... Stopper wall 33e ... Through hole 33f ... Recess 33g ... Recess 33h ... Recess 33k ... Through hole (vortex generating means)
38 ... bearing fixing ring 38a ... press-fitting fitting surface 38b ... first labyrinth forming surface 38c ... end surface on the load side (fixing ring position regulating surface)
38d ... 2nd labyrinth forming surface 42 ... Rolling bearing 42a ... Inner ring 42b ... Outer ring 42c ... Ball (rolling element)
DESCRIPTION OF SYMBOLS 100 ... Encoder 110 ... Encoder disc member 111 ... Hub part 200 ... Labyrinth 201 ... 1st narrow flow path 202 ... 2nd narrow flow path

Claims (8)

In the motor with an encoder provided with an encoder for detecting the rotation angle of the motor shaft on one end side in the axial direction of the motor casing,
A cylindrical wall provided at one end of the motor casing in the axial direction and through which the motor shaft is inserted on the inner peripheral side;
A rolling bearing in which an outer ring is fitted to the inner circumferential surface of the cylindrical wall, an inner ring is fitted to the outer circumferential surface of the motor shaft, and the motor shaft is rotatably supported with respect to the motor casing;
A hub portion that is provided on one end side in the axial direction from the rolling bearing of the motor shaft so as to rotate integrally with the motor shaft, and constitutes the encoder;
A spacer ring that is press-fitted between the rolling bearing and the hub portion on the outer peripheral surface of the motor shaft, and positions the inner ring of the rolling bearing in the axial direction, and positions the hub portion in the axial direction;
A stopper wall provided at a position corresponding to the other axial end of the rolling bearing on the inner peripheral surface of the cylindrical wall;
A bearing fixing ring that is press-fitted into a position corresponding to one end in the axial direction of the rolling bearing on the inner peripheral surface of the cylindrical wall, and cooperates with the stopper wall to restrict the outer ring of the rolling bearing in the axial direction; With
A motor with an encoder, characterized in that a labyrinth that captures an oily gas that tends to enter from the rolling bearing toward the encoder is provided between opposing surfaces of the spacer ring and the bearing fixing ring.   The motor with an encoder according to claim 1, wherein the spacer ring and the bearing fixing ring are made of metal. The spacer ring is
A ring body press-fitted into the outer peripheral surface of the motor shaft;
An annular body having an L-shaped cross section having a flange portion formed on one end side in the axial direction from the bearing fixing ring in the ring body and extending radially outward;
The outer peripheral surface of the ring main body is configured as a first labyrinth forming surface parallel to the inner peripheral surface of the ring main body,
The end surface of the ring main body that contacts the inner ring of the rolling bearing is configured as a spacer position regulating surface orthogonal to the outer peripheral surface and the inner peripheral surface of the ring main body,
The side surface of the flange portion on the bearing fixing ring side is configured as a second labyrinth forming surface parallel to the spacer position regulating surface,
On the other hand, the bearing fixing ring is an annular body having a rectangular cross section,
The inner peripheral surface of the bearing fixing ring is configured as a first labyrinth forming surface parallel to the outer peripheral surface of the bearing fixing ring,
The end surface of the bearing fixing ring that contacts the outer ring of the rolling bearing is configured as a fixed ring position regulating surface that is orthogonal to the inner and outer peripheral surfaces of the bearing fixing ring,
An end surface on one end side in the axial direction of the bearing fixing ring is configured as a second labyrinth forming surface parallel to the fixing ring position restriction surface,
The first labyrinth forming surface of the spacer ring and the first labyrinth forming surface of the bearing fixing ring face each other in parallel with a small radial distance therebetween, so that the first narrow flow path therebetween Formed,
The second labyrinth forming surface of the spacer ring and the second labyrinth forming surface of the bearing fixing ring are opposed to each other in parallel with a small gap in the axial direction, so that a second narrow flow is formed therebetween. A road is formed,
The labyrinth is formed by the narrow channel formed by forming a continuous narrow channel in which the first narrow channel and the second narrow channel are bent at a right angle. Item 3. A motor with an encoder according to item 1 or 2.   4. The motor with an encoder according to claim 3, wherein irregularities for increasing a surface area are formed on a surface of the flange portion of the spacer ring.   5. The motor with an encoder according to claim 4, wherein a concave portion is formed on a surface of the flange portion of the spacer ring so as to reduce a thickness of the flange portion.   4. A vortex generating means for generating an eddy current by rotation of the flange portion in an air flow passing through or after passing through the labyrinth is provided at or near the flange portion of the spacer ring. The motor with an encoder of any one of -5.   At least one of the ring main body and the flange portion of the spacer ring is provided with an oil reservoir for collecting a condensed component of the oily gas during or after passing through the labyrinth on the surface forming the labyrinth. The motor with an encoder according to claim 3, wherein the motor has an encoder.   The thickness increasing part which thickness increased from the inner peripheral side of this flange part is provided in the outer peripheral end part of the said flange part of the said spacer ring, The any one of Claims 3-7 characterized by the above-mentioned. A motor with an encoder described in 1.

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