JP2556184B2 - Electric motor for eccentric rotary motion having unbalance correction device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electric motor, and more particularly to an electric motor that includes an unbalance amount correction device and applies an eccentric rotation motion to a driven body.

[Conventional technology]

FIG. 3 is a half-body sectional view showing a main part of a conventional general eccentric rotation electric motor in which the tip end portion of the output shaft 1 is an eccentric shaft, and FIG. 4 is a needle bearing retainer of FIG. FIG. 4 is a view on arrow IV showing a state in which 7 and a needle bearing 8 are removed.

In FIGS. 3 and 4, the rotary shaft 1 has a center of rotation as X ₁ and is supported by ball bearings 2 and 3 on both sides in the axial direction of the electric motor, and a commutator 4 and an armature coil 5 of the electric motor are provided between the both bearings. And the armature core 5a has a rotating shaft 1
It is provided in an annular shape, and the tip of the output side of the rotary shaft 1 is Y ₁
Forming an eccentric part shaft 6 with the eccentric part as the eccentric center, and a needle bearing retainer 7, a needle bearing 8 and a slinger 9 are attached to the eccentric part shaft 6 from the outer end, and the eccentric part shaft 6 and the needle bearing retainer 7 are attached. The eccentric portion 10 constituted by the needle bearing 8 and the slinger 9 is combined with, for example, a pump assembly to generate hydraulic pressure.

[Problems to be Solved by the Invention]

In the electric motor having such a structure, unbalance occurs due to the eccentric portion 10, and in addition, there is a factor causing unbalance in the winding of the armature coil 5, and also unbalance occurs in the impregnation of the varnish for insulation. Further, the unbalance of the eccentric portion 10 is added to cause a large unbalance amount, but conventionally, these unbalances are corrected by the balance putty 11 to prevent the danger due to the vibration at the time of rotating the electric motor.

Since this balance putty is considerably large in amount, the material cost is high, which is a factor in the cost as well as the number of correction steps.

Further, since manufacturing of the eccentric shaft requires special technology, there is a problem that the manufacturer is limited.

[Means for solving the problem]

To solve the above problems, according to the present invention, (1) the output-side shaft of the electric motor is not eccentric, but is concentric with the shaft of the rotating shaft, and the inner ring of the needle bearing is eccentric to cause eccentric motion; The slinger for holding the bearing and the outer peripheral portion of the needle bearing retainer in the eccentric direction are notched so that the center of gravity of the eccentric portion is displaced to the side opposite to the eccentric direction with respect to the rotating shaft to minimize unbalance.

 The above two measures have solved the problem.

[Work]

Instead of providing an eccentric shaft on the motor shaft, the eccentric part has a structure that uses an eccentric needle bearing that is relatively easy to manufacture, and it operates exactly the same as a conventional eccentric part, and a slinger that holds the eccentric needle bearing. Since the needle bearing retainer is provided with a notch or the like to provide an imbalance on the side opposite to the actual imbalance, the imbalance of the armature assembly due to the presence of the eccentric portion can be reduced as much as possible.

〔Example〕

FIG. 1 is a sectional view of a main half body showing an embodiment of an electric motor unbalance correction device according to the present invention, and FIG. 2 is a view taken along the line II-II of FIG.

In FIGS. 1 and 2, the motor shaft 21 is supported by ball bearings 22 and 23, and a commutator 24, an armature coil 25, and an armature core 25a are provided between the two bearings in an annular shape with respect to the shaft 21, respectively. One end of the motor shaft 21 becomes a small-diameter shaft portion 26, and an eccentric needle bearing 28 having a needle bearing retainer 27 and an eccentric inner ring 28a and a slinger 29 are attached to the small-diameter shaft portion 26 in order from the outer end, and the small-diameter shaft portion is attached. Part 26,
Needle retainer 27, eccentric needle bearing 28, slinger 29
An eccentric portion 30 constituted by is combined with, for example, a pump assembly to generate hydraulic pressure.

Here, by calculation or experimental data, in order to cause unbalance in the opposite direction to the unbalance of the eccentric type needle bearing 28,
Notches are provided on the needle bearing retainer 27 and the slinger 29, respectively.
27a and 29a are processed, and a balance putty 31 is attached as necessary by a balance test to correct the imbalance.

〔The invention's effect〕

As described above, since the eccentric type needle bearing is used instead of the eccentric shaft, the manufacturing is much easier, the manufacturing of the rotary shaft is not limited to a special manufacturer, and the needle bearing retainer and the slinger are not separated. By processing the notch to reduce the imbalance in the initial stage, it becomes easy to correct the imbalance,
Compared to the conventional repair work, the balance putty can be used in a small amount, the number of work steps is small, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a main half body of an embodiment of an electric motor unbalance correction device according to the present invention, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIG. 3 is a conventional electric motor having an eccentric shaft. FIG. 4 is a sectional view of the main half body of FIG. 4, showing the needle bearing and the needle bearing retainer of FIG. (Explanation of symbols) 1 ... eccentric shaft, 2, 3 ... ball bearing 4 ... commutator, 5 ... armature coil 5a ... armature core, 6 ... eccentric shaft 7 ... needle bearing retainer, 8 ... Needle bearing 9 …… slinger, 10 …… eccentric part 11 …… balance putty, 21 …… motor shaft 22,23 …… ball bearing, 24 …… commutator 25 …… armature coil 25a …… armature core 26 …… small diameter shaft Part, 27 …… Needle bearing retainer 27a …… Notch, 28 …… Eccentric needle bearing 28a …… Eccentric inner ring, 29 …… Slinger 29a …… Notch, 30 …… Eccentric part 31 …… Balance putty X ₁ … … Motor center axis X ₂ …… Motor and shaft center axis Y ₁ …… Eccentric shaft and needle bearing center axis Y ₂ …… Needle bearing center axis

Claims (1)

(57) [Claims] 1. A rotary shaft having no eccentric portion, a ball bearing supporting the rotary shaft on the load side and the other side of the electric motor, and an externally fitted axially outer side of the load side ball bearing, A needle bearing whose inner ring is eccentric with respect to the axis of the rotary shaft of the electric motor to give an eccentric rotary motion to the load; and a slinger which holds the needle bearing from the axial inner side to the output shaft,
A needle bearing retainer for holding the needle bearing against the output shaft from the outside in the axial direction thereof, wherein the slinger and the needle bearing retainer have a center of gravity of an eccentric portion of the needle bearing depending on an unbalanced amount thereof. To be compensated,
An electric motor for eccentric rotary motion having an unbalance correction device, characterized in that an unbalance correction device is formed by cutting out the outer peripheral portion of the needle bearing in the eccentric direction.