JP2009254159A - Motor with brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor with brush, wherein bearing oil is suppressed from sticking to the outer peripheral surface of a commutator and installing of the commutator inside a housing is made easy. <P>SOLUTION: A motor 10 with a brush comprises a rotating shaft 50 of which a tip end 50a is rotatably supported by a housing 20 through a bearing 28, a commutator 70 which is supported by the rotating shaft 50 and rotates together with the rotating shaft 50, and a brush 80 which slides on the outer peripheral surface of the commutator 70. The commutator 70 comprises a swollen part 72 that expands along the axial direction X of the rotating shaft 50, toward the bearing 28. The tip end face 72a of the swollen part 72 is formed vertically to the axial direction X of the rotating shaft 50 and comprises taper grooves 74, becoming narrower in radial direction as advances outward, across the entire circumference of the rotating shaft 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor with a brush including a brush that is in sliding contact with an outer peripheral surface of a commutator.

  As a motor for generating a rotational driving force, a motor with a brush is widely used. In this type of motor, a permanent magnet is fixed to the inner wall of a housing, and a rotor around which an armature coil is wound is rotatably supported. And in order to energize an armature coil, a pair of electroconductive brush is installed in the position shifted 180 degrees along the circumferential direction so that it may slidably contact with the outer peripheral surface of the commutator of a rotor.

  In this brush motor, when the rotor rotates, the bearing oil for the bearing that supports the rotating shaft of the rotor tends to move along the rotating shaft. This phenomenon is due to the pumping effect and the effect of surface tension. If this bearing oil adheres to the outer peripheral surface of the commutator, it adversely affects the commutation and motor performance.

As such a motor with a brush that suppresses adhesion of bearing oil to the outer peripheral surface of the commutator, a motor with a brush provided with an oil draining and oil recovery structure has been conventionally known (for example, see Patent Document 1). ). This oil draining and oil recovery structure is installed on the axial end face of the cylindrical commutator, and is formed in an annular shape that is continuously curved so as to expand toward the bearing. Thereby, the bearing oil which has moved from the bearing to the commutator along the rotating shaft can be scattered back to the bearing again, and adhesion of the bearing oil to the outer peripheral surface of the commutator can be suppressed.
JP 2005-130695 A

  However, the oil draining and oil recovery structure having the above-described conventional configuration is formed in a continuously curved annular shape so as to expand toward the bearing, and thus is easily damaged when pressed in the axial direction. For this reason, it is difficult to press the commutator in the axial direction and install it at a predetermined position in the housing.

  The present invention has been made in view of the above, and provides a brushed motor that suppresses adhesion of bearing oil to the outer peripheral surface of the commutator and facilitates installation of the commutator in the housing. Objective.

In order to achieve the above object, the first invention provides a rotating shaft whose tip is rotatably supported by a housing via a bearing, a commutator supported by the rotating shaft and rotating together with the rotating shaft, and the commutator. In a brushed motor comprising a brush slidably contacting the outer peripheral surface of
The commutator includes a bulging portion that bulges in the axial direction of the rotating shaft toward the bearing,
The distal end surface of the bulging portion is formed perpendicular to the axial direction of the rotating shaft, and includes a group of tapered grooves that taper radially outward over the entire circumferential direction of the rotating shaft.

Further, the second invention provides a rotating shaft whose tip is rotatably supported by a housing via a bearing, a commutator supported by the rotating shaft and rotating together with the rotating shaft, and a sliding surface on the outer peripheral surface of the commutator. In a motor with a brush provided with a brush in contact,
The commutator includes an insulator in which a through hole for inserting the rotating shaft is formed, and a plurality of commutator pieces installed at predetermined intervals along a circumferential direction of the insulator,
The insulator includes a bulging portion that bulges from the commutator piece in the axial direction of the rotating shaft toward the bearing,
The front end surface of the bulging portion is formed perpendicular to the axial direction of the rotation shaft, and tapers radially outward over the opening edge of the through hole and the entire circumference of the opening edge. A taper groove group.

  ADVANTAGE OF THE INVENTION According to this invention, the motor with a brush which makes the installation in the housing of a commutator easy while suppressing adhesion of the bearing oil to the outer peripheral surface of a commutator can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a partial cross-sectional view schematically showing an embodiment of a brushed motor according to the present invention. The brushed motor 10 according to the present embodiment includes a housing 20, a field permanent magnet 30 fixed to the inner wall of the housing 20, and a rotor 40.

  The housing 20 is configured by combining a storage case 22 that stores the rotor 40 and a lid member 24 that closes the storage chamber R of the storage case 22 from the right side. The storage case 22 is formed in a cylindrical shape, and a permanent magnet 30 is fixed to the inner wall at the center in the axial direction X over the entire circumference in the circumferential direction.

  A rotor 40 is inserted inside the permanent magnet 30 so as to be rotatable in the circumferential direction. In the storage chamber R of the storage case 22, a space for storing the rotor 40 is formed.

  Next, the configuration of the rotor 40 will be described. The rotor 40 includes a rotation shaft 50, an armature 60 supported by the rotation shaft 50 and rotating together with the rotation shaft 50, an armature coil (not shown) of each phase wound around the armature 60, and a rotation shaft. 50 and a commutator 70 that is supported by the rotary shaft 50 and rotates with the rotary shaft 50.

  The rotating shaft 50 is disposed coaxially with the cylindrical housing 20, and the tip 50 a is rotatably supported by the housing 20 via the bearing 28.

  The armature 60 and the armature coil are attached so as to face and face the inner peripheral surface of the permanent magnet 30 fixed to the inner wall of the storage case 22, and rotate inward in the radial direction of the permanent magnet 30.

  The commutator 70 supplies current supplied from a brush 80 described later to the armature coil. As the commutator 70 rotates, a rectifying action is performed in which the direction of the current flowing through the armature coil is changed in the reverse direction. As a result, magnetic flux is generated around the rotor 40, and a rotational force that rotates the rotor 40 with respect to the field magnetic field from the permanent magnet 30 is generated. Details of the commutator 70 will be described later.

  The brush 80 supplies current from a power source (not shown) to the commutator 70 and extends in the radial direction of the commutator 70 so as to be in sliding contact with the outer peripheral surface of the commutator 70 formed in a cylindrical shape. It was provided. That is, the slidable contact surface of the brush 80 is formed in an arc shape having the same diameter as the radius of curvature of the outer periphery of the commutator 70. The pair of brushes 80 is in sliding contact with the outer peripheral surface of the commutator 70 at a position shifted by 180 ° along the circumferential direction of the commutator 70 and supplies current from the power source.

  2A and 2B are schematic views illustrating a configuration example of the commutator 70, in which FIG. 2A is a front view and FIG. 2B is a cross-sectional view taken along line AA in FIG.

  The commutator 70 of the present embodiment includes a bulging portion 72 that bulges in the axial direction X of the rotary shaft 50 toward the bearing 28 as a characteristic configuration. A tip end surface 72a of the bulging portion 72 is formed perpendicular to the axial direction X of the rotating shaft 50, and is a tapered groove group that tapers radially outward over the entire circumferential direction of the rotating shaft 50. 74.

  For example, as shown in FIG. 2, the commutator 70 is installed at a predetermined interval along a circumferential direction of the insulator 94 and a cylindrical insulator 94 in which a through hole 92 into which the rotary shaft 50 is inserted is formed. And a plurality of arcuate cylindrical commutator pieces 96. The insulator 94 includes a bulging portion 72 that bulges from the commutator piece 96 in the axial direction X of the rotary shaft 50 toward the bearing 28. The distal end surface 72a of the bulging portion 72 is formed perpendicular to the axial direction X of the rotating shaft 50, and radially outwards over the opening edge 92a of the through hole 92 and the entire periphery of the opening edge 92a. And a tapered groove group 74 which is tapered.

  Each taper groove 74 is formed in a V-shaped or U-shaped cross section, for example. Each taper groove 74 has a groove width that becomes narrower and a groove depth that becomes shallower outward in the radial direction of the rotating shaft 50, and terminates at the outer peripheral surface of the bulging portion 72. The tapered groove group 74 is formed in a star shape with the rotational axis 50 as the center when viewed from the front.

  The commutator pieces 96 are separated from each other so as not to short-circuit each other. When the current supplied to the brush 80 flows through the armature coil through each commutator piece 96 of the commutator 70, a magnetic flux is generated around the rotor 40, and this magnetic flux is attracted and repelled by the field magnetic flux of the permanent magnet 30. The rotor 40 rotates by repeating the above.

Here, the function of the bulging portion 72 will be described with reference to FIGS. FIG. 3 is a schematic diagram for explaining the function and function of the bulging portion 72 when the bearing oil moves from the bearing 28 to the commutator 70 along the rotary shaft 50. FIG. The front view equivalent to a), (b) is sectional drawing equivalent to FIG.2 (b). FIG. 4 is a schematic view for explaining the function and function of the bulging portion 72 when the commutator 70 is mounted in the housing 20, and is a cross-sectional view corresponding to FIG. 2 (b). The action and function of the bulging portion 72 when the oil G moves from the bearing 28 to the commutator 70 along the rotary shaft 50 will be described with reference to FIG.

  When the bearing oil G moves from the bearing 28 to the commutator 70 in the direction of the arrow B along the rotary shaft 50, the bearing oil G comes into contact with the tip surface 72 a of the bulging portion 72. A tapered groove group 74 is formed on the distal end surface 72 a of the bulging portion 72 over the entire circumference in the circumferential direction of the rotating shaft 50. For this reason, the bearing oil G that has moved along the rotating shaft 50 adheres to the tapered groove group 74 on the rotating shaft 50 side. The bearing oil G adhering to the taper groove group 74 moves in the direction of arrow D along each taper groove 74 that tapers radially outward due to the centrifugal force associated with the rotation of the rotor 40 in the direction of arrow C. To do.

  Since the groove width of each taper groove 74 becomes narrower as it goes outward in the radial direction, the oil droplets G merge. Moreover, since the rotational peripheral speed increases as going outward in the radial direction, the centrifugal force acting on the oil droplet G becomes stronger. Thus, since the oil droplet G is increased in volume and accelerated as it goes outward in the radial direction, the oil droplet G is scattered at the end of each taper groove 74 and the oil is drained.

  Moreover, the groove depth of each taper groove 74 becomes shallow, so that it goes to radial direction outward. For this reason, the moving direction (arrow D direction) of the oil droplet G is inclined in the direction approaching the bearing 28 from the radially outer side. As a result, the oil droplets G are scattered toward the bearing 28 at the end of each taper groove 74, and the oil is drained.

  Thereby, adhesion of the oil droplet G to the outer peripheral surface of the commutator 70 can be suppressed.

  Next, the operation and function of the bulging portion 72 when the commutator 70 is mounted in the housing 20 will be described with reference to FIG.

  In order to mount the commutator 70 in the housing 20, when the cylindrical press-fitting jig 100 is inserted from the bearing 28 into the housing 20 along the axial direction X in the direction of arrow B, the front end surface 100 a of the press-fitting jig 100. Comes into contact with the distal end surface 72 a of the bulging portion 72. When the press-fitting jig 100 is further inserted in the arrow B direction in this state, the tip end surface 72 a of the bulging portion 72 is pressed in the axial direction X.

  The distal end surface 72 a of the bulging portion 72 is formed perpendicular to the axial direction X, and the bulging portion 72 bulges in the axial direction X. Since the bulging portion 72 receives the pressing force in the axial direction X at the distal end surface 72a, it is less likely to be damaged than in the case of the conventional example. As a result, the commutator 70 can be pressed by the press-fitting jig 100 and attached to a predetermined position in the housing 20.

  Thereby, installation in the housing 20 of the commutator 70 can be made easy.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the commutator 70 of the present embodiment, the through hole 92 is formed through the insulator 94 and the rotating shaft 50 is inserted into the through hole 92. However, the commutator 70 is supported by the rotating shaft 50 and rotated. As long as it can rotate with the shaft 50, the configuration is not limited. For example, the commutator 70 and the rotating shaft 50 may be integrally formed.

  Further, although a pair of brushes 80 according to the present embodiment are installed at positions shifted by 180 ° along the circumferential direction of the commutator 70, the number of the brushes 80 is not limited as long as the commutation action is performed with the rotation of the commutator 70. There is no limit.

It is a partial sectional view showing typically one example of a motor with a brush of the present invention. 3 is a schematic diagram illustrating a configuration example of a commutator 70. FIG. It is a schematic diagram for demonstrating the effect | action and function of the bulging part 72 in case a bearing oil moves along the rotating shaft 50 from the bearing 28 to the commutator 70. FIG. FIG. 6 is a schematic diagram for explaining the function and function of the bulging portion 72 when the commutator 70 is mounted in the housing 20.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motor with brush 20 Housing 28 Bearing 40 Rotor 50 Rotating shaft 50a Tip of rotating shaft 50 70 Commutator 74 Tapered groove group (tapered groove)
80 Brush 90 Insulator 92 Through-hole 92a Opening edge of through-hole 92 94 Insulator

Claims (2)

A brushed motor comprising: a rotating shaft whose tip is rotatably supported by a housing via a bearing; a commutator that is supported by the rotating shaft and rotates together with the rotating shaft; and a brush that is in sliding contact with the outer peripheral surface of the commutator. In
The commutator includes a bulging portion that bulges in the axial direction of the rotating shaft toward the bearing,
A brush provided with a tapered groove group that is formed perpendicular to the axial direction of the rotating shaft and tapered radially outward over the entire circumferential direction of the rotating shaft. With motor. A brushed motor comprising: a rotating shaft whose tip is rotatably supported by a housing via a bearing; a commutator that is supported by the rotating shaft and rotates together with the rotating shaft; and a brush that is in sliding contact with the outer peripheral surface of the commutator. In
The commutator includes an insulator in which a through hole for inserting the rotating shaft is formed, and a plurality of commutator pieces installed at predetermined intervals along a circumferential direction of the insulator,
The insulator includes a bulging portion that bulges from the commutator piece in the axial direction of the rotating shaft toward the bearing,
The front end surface of the bulging portion is formed perpendicular to the axial direction of the rotation shaft, and tapers radially outward over the opening edge of the through hole and the entire circumference of the opening edge. A brushed motor comprising a tapered groove group.

Images