JPH07184344A - Motor for electric-operated pump - Google Patents

Abstract

PURPOSE:To prevent the unbalance of an armature shaft by providing a hole in a position cancelling the eccentricity of the armature shaft due to the eccentric part of a core sheet fitted into the armature shaft. CONSTITUTION:The core 20 of an armature shaft 3 is formed by laminating a core sheet (CS) 5 and pressed into the armature shaft (AS) 7 for fixation. A hole 21 is provided in a plurality of core sheets (CS) 5 by punching it with press work or the like. The eccentric part 8 of the armature shaft (AS) 7 causes eccentricity downward on the basis of the central axis of the armature shaft (AS) 7 in a static condition. At that time, a hole 21a which is formed by punching the respective core sheets (CS) 5 in the eccentric direction due to the eccentric part 8, is provided to avoid eccentricity. Thereby, the center of gravity in the direction of the central axis of the armature shaft (AS) 7 and the armature core 20 can be moved upward. A hole 21b is provided by a similar method to the hole 21a in the position apart from the eccentric part 8 as compared with the hole 21a for the balance at the time of the rotation of the armature sheet (AS) 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric pump motor for pumping oil or the like, and more particularly to an electric pump motor for driving a piston pump to pump oil.

[0002]

2. Description of the Related Art In an electric pump motor for driving a piston pump to pump oil or the like, a piston pump 104 is conventionally mounted on an armature shaft 107, which is a rotating shaft of the electric pump motor, as shown in FIG. An eccentric portion 108 is provided for driving. In addition, an eccentric cam (not shown) may be used instead of the armature shaft eccentric portion 108. In this case, the armature shaft is unbalanced by the eccentric part 108 or the eccentric cam, and smooth rotation is hindered.

In order to solve such a problem, there is a rotor of an electric piston pump motor disclosed in Japanese Patent Laid-Open No. 4-248345. In this conventional technique, first and second balance weights are attached to the shaft on both sides of the core in order to eliminate the eccentricity due to the armature shaft eccentric portion for driving the piston pump.

[0004]

However, in the electric pump motor 100 adopting the above-mentioned structure, the first and second balance weight parts are always required in order to ensure the smooth rotation of the armature shaft 107. Therefore, it is also necessary to attach this part to the armature shaft during the production process. This not only hinders the productivity improvement of the electric pump motor 100, but also causes a cost increase.

Further, since the balance weight is attached to the armature 102 on both sides of the core, there is a problem that the size and shape of the balance weight are limited. Therefore, it is an object of the present invention to provide an electric pump motor that is low in cost and that can easily prevent unbalance of the armature shaft when driving the motor.

[0006]

In order to solve the above-mentioned problems, an electric pump motor according to claim 1 of the present invention comprises an eccentric part on an armature shaft, which is a rotating shaft of the motor, for driving a piston pump. In the motor for an electric pump provided with, when the armature shaft rotates, an unbalanced portion due to an eccentric portion is fitted to the armature shaft at a position where the eccentricity of the armature shaft due to the eccentric portion of the plurality of core sheets is canceled. It is characterized in that a hole portion to be avoided is provided.

Further, the hole portion is eccentric when the armature shaft is rotated, with the central axis of the armature shaft having an inclination in the eccentric direction of the armature shaft by the eccentric portion and in the direction of canceling the eccentricity. The electric pump motor according to claim 1, which is provided at a position for canceling the unbalance, may be adopted.

[0008]

When the motor for the electric piston pump having the eccentric part is driven to drive the piston and the armature shaft, which is the output shaft, rotates, the unbalance due to the eccentric part and the hole formed in the armature core sheet Unbalance and offset each other. In this way, the unbalance of the armature shaft is adjusted so that it can rotate smoothly.

[0009]

The present invention will be described below with reference to the embodiments shown in the drawings. 1 and 3 show an electric pump motor 50 according to an embodiment of the present invention. In the electric pump motor 50, the pump housing 1 is formed into a substantially columnar shape by die casting or the like, and has a suction port 31 and a discharge port 32 for a fluid such as oil to be pressure-fed. A support bearing 9 of the armature 3 is fixed to the pump housing 1 with a housing recess processing portion 12 with resin or the like, and a stator 4 of the motor 2 is also screwed with a screw 6. Further, the pump housing 1 is provided with a pump portion 17 in the radial direction thereof. The pump portion 17 is fixed to the pump housing 1 by a screw 18. The piston 19 is in contact with the eccentric bearing 10 which is press-fitted into the eccentric portion 8 of the armature shaft 7. The details of such a pump structure are well known, and the description thereof will be omitted.

Next, the pump drive motor 2 will be described. The pump drive motor 2 is configured as a magnet type DC motor, and supplies current to the armature shaft 7, which is an output shaft, the armature 3 provided on the armature shaft 7, and the winding 16 wound around the armature 3. The commutator 14 is provided. The pump drive motor 2 is slidably in contact with a cylindrical stator 4 fixed to the pump housing 1, an arcuate magnet 15 fixed inside the stator 4 so as to face the armature core 20, and a commutator 14. The brushes 24 and 26 are provided.

As shown in FIG. 3, the plus brush 24 of the motor 2 is connected to the terminal 13 via the terminal 25, and this terminal 13 is connected to a plus power source (not shown). The minus brush 26 has terminals 27 and 2.
It is connected to the pump housing 1 via 8. The pump housing 1 has terminals 25, 27, 28 connected to a negative power source (not shown), and the resin brush holder 3 has terminals.
No. 0 is integrally molded, and this resin brush holder 30
Are fixed to the pump housing 1 by screws 29. Electric power is supplied to the motor 2 in such a configuration.

Here, the armature 3 is a support bearing 9
And 11 support the pump housing 1 in a cantilever manner. The core 20 of the armature 3 is formed by stacking the core sheets 5, and is fixed to the armature shaft 7 by press fitting. As shown in FIG. 2, a plurality of core sheets 5
Each of them is provided with a hole portion 21 punched by press working or the like. Here, the eccentric portion 8 of the armature shaft 7 is eccentric downward in FIG. 2 with respect to the central axis of the armature shaft 7 in the static state. In such a case, in order to avoid the above-described eccentricity, holes 21a formed by punching out the core sheet 5 are provided in the eccentric direction by the eccentric part 8. As a result, the center of gravity of the armature shaft 7 and the armature core 20 in the central axis direction can be moved upward in FIG. Further, for balance when the armature shaft 7 rotates, the hole 21b is provided at a position farther from the eccentric portion 8 than the hole 21a in the same manner as the hole 21a. In this case, the hole 21b corresponds to the eccentricity of the armature shaft 7 by the eccentric part 8 by optimally forming such holes 21a, 21b provided in the direction opposite to the eccentric direction of the armature shaft 7, and the motor 2 is Make it rotate smoothly.

Here, as described above, the holes 21a, 21
b is provided at a symmetrical position with respect to the armature shaft 7 and is provided with the distance from the eccentric portion 8 as described above. This is because when the armature shaft rotates, The centrifugal force applied to the position causes the weight of the eccentric portion 8 and the hole 21.
a and 21b act on the removed weight due to formation,
This is to minimize the occurrence of even imbalance in which the central axis of the armature shaft 7 is displaced with a certain inclination.

The holes 21a, 21 formed in this way
One method for determining the optimum position of b and the optimum removal weight will be described in the following equations 1 to 5.

[0015]

[Formula 1] U1 = (M1 + M2) * e

[0016]

[Formula 2] U2 = m * l * Nl

[0017]

[Formula 3] U3 = m * l * Nr

[0018]

(4) U = U1-U2 + U3

[0019]

[Formula 5] Uc = {L1 / (L1 + L2)} * U1− {L2 / (L1 + L2)} * U3 However, the distance from the center of the left part of the L1 and armature core 20 to the center of the eccentric part L2 and the armature core 20 Distance from the center of the right part to the center of the left part of the armature e ・ Eccentric amount of the eccentric part 8 with respect to the armature shaft M 1 ・ Weight of the eccentric bearing 10 M 2 ・ Weight of the eccentric part 8 of the armature shaft m ・ Each core sheet Mass of hole 1 · Each hole 21a from the central axis of the armature shaft 7,
Distance to the center of gravity of b b Nl ・ Number of core sheets 5 on the left side of the armature core 20 Nr ・ Number of core sheets 5 on the right side of the armature core 20 U1 ・ Moment at the eccentric part U2 ・ Moment at the left side of the armature core 20 U3 ・Moment in the right part of the armature core 20 U · Armature core 20 and armature shaft 7 imbalance in the stationary state Uc · Armature core 20 and armature shaft 7
In the above equation, the unbalance amount U of the armature core 20 and the armature shaft 7 in the stationary state becomes 0, and the rotation state of the armature core 20 and the armature shaft 7 Of the core sheet so that the unbalanced amount of the core sheet, that is, the even unbalanced amount is 0.
b mass Nl * m, Nr * m, and the distance l from the center axis of the armature shaft 7 to the center of gravity of each hole 21a, 21b
To decide. The holes 21a and 21b are provided on the basis of the position and the weight thus determined.

With the above-mentioned structure, the imbalance due to the eccentric portion 8 can be corrected without mounting the balance weight on the armature shaft as in the conventional case. The holes 21a and 21b formed in the armature core 20 can be formed at the same time when the winding 16 is formed by punching the slot portion 22 of the core sheet 5 or the press-fitting portion 23 into the armature shaft 7. Therefore, the configuration for correcting the imbalance of the eccentric portion 8 can be realized without adding a special process. In addition, the hole 21a is formed between the left part and the right part of the armature core 20,
When forming 21b, the core sheet 5 used for forming the left part and the right part of the armature core 20 may have the same shape. Because, when press-fitting the core sheet 5 having the same shape into the armature shaft 7,
This is because the holes 21a and 21b can be formed by reversing and assembling. As described above, by adopting such an armature core 20, it is possible to significantly reduce the cost and improve the productivity.

As described above, the inside of the armature core 20, that is, the armature core sheet 5, can be made to have the conventional balance weight effect. Therefore, the winding 16 wound around the slot portion 22 and the commutator 14 are There is no fear of damage, and the armature 3 and hence the pump drive motor 2 can be downsized.

The present invention is not limited to the above embodiment, but can be variously modified as follows. For example, although the armature shaft 7 itself has the eccentric portion 8 which is eccentric in the above-mentioned embodiment, an eccentric cam is attached to the coaxial shaft, and the eccentric bearing 1 is attached thereto.
The same effect can be obtained with 0 installed.

Further, in the above embodiment, the eccentricity of the armature shaft was corrected by optimally punching out the core sheet 5 of the armature core 20 and providing the armature core 20 with a hole portion. It is also possible to correct by cutting the armature shaft 7 itself or providing a hole in the armature shaft 7 itself.

Further, in the above-mentioned embodiment, the same core sheet 5 is used for both the left part and the right part of the armature core 20, but a core sheet having different punched hole parts in the left part and the right part is used. Is also possible. Further, in the above-described embodiment, the holes 21a and 21b are arranged in the eccentric direction of the eccentric part 8 and the opposite direction in order to correct the imbalance due to the eccentric part 8, but three holes are provided.
Alternatively, the imbalance may be corrected by providing four or more places. In this case, the total of the masses of the three or four or more hole portions is set to be the above masses Nr * m and Nl * m. Further, the centers of gravity of the plurality of holes that exert the effect of the hole 21a described above are set so as to coincide with the center of the hole 21a. Similarly, the centers of gravity of the plurality of holes that exhibit the effect of the hole 21b are set to coincide with the center of the hole 21b. As described above, a plurality of holes may be arranged in the armature core 20.

Further, in the above-mentioned embodiment, the core sheet 5 having the same shape and having the similarly punched holes 21 is formed.
Was rotated 180 ° and press-fitted into the armature shaft to form the holes 21a and 21b. However, if the distance between the eccentric part of the armature shaft and the armature core is not relatively large, regardless of this, a plurality of holes with different shapes may be formed in the core sheet in advance at one location or around the center of rotation. By punching and setting each of these holes to an optimum size, the eccentricity due to the eccentric portion can be corrected without rotating the core sheet when press-fitting into the armature shaft.

[0026]

As described above in detail, according to the present invention, it is possible to provide a motor for an electric pump which can suppress the cost and easily prevent the imbalance of the armature shaft when the motor is driven.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of an electric pump motor according to the present invention.

FIG. 2 is a diagram of an armature shaft and an armature core showing an embodiment of a motor for an electric pump according to the present invention.

FIG. 3 is a front view showing an embodiment of an electric pump motor according to the present invention.

FIG. 4 is a side view showing a conventional electric pump motor.

[Explanation of symbols]

 1 Pump housing 2 Pump drive motor 3 Armature 8 Eccentric part

Claims (2)

[Claims] 1. A motor for an electric pump, wherein an eccentric portion is provided on an armature shaft, which is a rotation shaft of the motor, for driving a piston pump. The motor is fitted into the armature shaft when the armature shaft rotates. A motor for an electric pump, characterized in that a hole portion for avoiding unbalance due to the eccentric portion is provided at a position where the eccentric portion of the plurality of core sheets cancels the eccentricity of the armature shaft. 2. When the armature shaft is rotated, the hole is eccentric with an inclination of a central axis of the armature shaft in an eccentric direction of the armature shaft by the eccentric part and a direction of canceling the eccentricity. The electric pump motor according to claim 1, wherein the electric pump motor is provided at a position to cancel the unbalance.