JPS63132016A - Molding method for rotor with resin - Google Patents

Abstract

PURPOSE:To prevent an inserted body from an unexpected displacement in a cavity, by filling a resin into the cavity from respective gates being set on both sides of a core and setting the resin filling speeds at the gates of the both sides at the same value in the initial resin filling stage. CONSTITUTION:An inserted body, where a commutator 3 and a core 4 prepared by winding a coil are provided on a rotating shaft 2 to sheathe it, is kept on a bottom force 12 and a top force 11 is fit to the bottom force 12. The mold is clamped and the core 4 is properly contained in a cavity 13. A resin is sent under pressure into runners 18A and 18B and applied into the cavity 13 through the first gates 16A and 16B and the second gates 17A and 17B. Since the hole areas of the second gates 17A and 17B are set larger than those of the first gates 16A and 16B, the resin filling speeds at the first gates and the second gates become the same value on the initial resin filling stage though the second gates is positioned at the downstream of the first gates. The core 4 is thereby not moved in the direction of the second gate side on the rotating shaft 2.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of resin molding a rotor having a resin package outside the armature, and in particular, a method of molding a rotor with a resin on both sides of the core in a cavity in which the armature is housed. The present invention relates to a method of molding a resin package by filling the resin from each gate, and relates to a method that is effective for molding, for example, a rotor of an in-tank fuel supply bomb-integrated heptad.

[Conventional technology]

Generally, there is an in-tank type pump that is installed inside the fuel tank as a pump that supplies fuel to a car. There is something configured. The rotor used in this type of motor has an armature that is encased in a cylindrical rotating shaft and is surrounded by a resin pancage.This package prevents the armature from being eaten by the fuel. There are some that are configured to suppress viscous resistance with the rotating fuel.

Conventionally, such a resin pancage for a rotor is molded by accommodating an armature in a cavity and filling the cavity with resin through gates arranged on both sides of the core.

[Problem that the invention seeks to solve]

However, in this type of molding method, the core cannot be firmly fixed to the rotating shaft because the rotating shaft is formed in a cylindrical shape, so the core is pushed by the resin that is pumped from the side and rotates. It may be moved in the axial direction on the shaft.

An object of the present invention is to provide a resin molding method for a rotor that can prevent unexpected movement of an insert within a cavity.

[Means for solving problems]

A rotor resin molding method according to the present invention is a rotor resin molding method in which a cavity in which an armature as an insert is housed is filled with resin through a pair of gates arranged on both sides of a core. The invention is characterized in that resin filling speeds at both gates are set to be the same speed at the beginning of the process.

[Effect]

According to the above-mentioned means, since the filling speeds on both sides of the insert are the same at the initial stage, the forces acting on the insert from both directions due to the filling resin cancel each other out.

Therefore, the insert will not be moved by the filling resin within the cavity.

〔Example〕

Fig. 1 is a plan sectional view showing a rotor resin molding method according to an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the molded rotor, and Fig. 3 shows a molding device used therein. It is an exploded perspective view.

In this example, the resin molding method for the rotor is commonly used for molding the resin puff cage of the rotor in an in-tank fuel supply pump integrated motor, and the molding gamma shown in FIG. be done. As shown in FIG. 2, the rotor 1 has a cylindrical rotating shaft 2, a core 4 with a coil wound around it, and a commutator 3, which constitutes an armature. The resin package 5 is formed by molding the resin package 5. The rotating shaft 2 is formed into a cylindrical shape so that it can be rotatably attached to a support shaft (not shown) that extends between the motor housing and the pump casing in order to integrate the motor and the pump into one unit. 6 Since the rotating shaft 2 is formed in a cylindrical shape, the core 4 cannot be strongly press-fitted onto the rotating shaft 2, and as a result, the core 4 moves relatively on the rotating shaft 2 in the axial direction. It's getting easier.

The molding apparatus 10 shown in FIG. 3 includes an upper mold 11 and a lower mold 12 that are matched with each other, and the mating surfaces of the upper mold 11 and the lower mold 12 have a pair of upper and lower recesses 13a, 13b
are respectively recessed so as to cooperate with each other to constitute a cavity 13 for molding the resin package of the rotor.

A pair of upper and lower recesses 14a, 14 is provided on one side of the cavity recesses 13a, +3b on the mating surfaces of the upper and lower molds 11.12.
b are respectively recessed so as to cooperate with each other to constitute a holding part for holding the protruding end of the rotating shaft 2,
Similarly, on the other side, a pair of upper and lower recesses 15a and 15b are recessed so as to cooperate with each other to form a holding section for holding the commutator 3. A pair of first gates 16A and 16B are arranged on both sides of the body of the cavity recess 13b on the mating surface of the lower mold 12 at positions closer to the rotary shaft holding recess 14b.
Similarly, a pair of second gates 1-17A and 17'13 are respectively opened at positions near the commutator holding recess 15b so as to communicate with the cavity 13. .

A pair of runners 18A and 18B are recessed in the mating surface of the lower mold 12, respectively, and are arranged on both sides of the cavity recess 13b.
Gates 16A, 16B and both cylinders 2 gates 1-17A, 1
7B are connected to communicate with each other at the ends opposite to the cavity recess 13b. Both runners 18A, 18B are joined to each other on the side where the first gates +6A, 16B are connected, and then connected to a filling resin supply source (not shown) such as an injection molding machine or the like. . Therefore, the first gates 16A, 16B are located upstream of the second gates 17A, 1713 with respect to the flow of the filled resin.

In this embodiment, the first gates 16A, 16B
The second gates 17A, 17B are formed such that the opening area of the second gate located on the downstream side is larger than the opening area of the first gate on the upper liquid side. The opening area ratio between the two is appropriately set so that the filling resin speeds at the initial stage of resin filling are approximately equal to each other.

Next, an embodiment of the rotor resin molding method according to the present invention will be described by explaining the usage and operation of the rotor resin molding apparatus according to the above structure.

First, an insert article, which is equipped with a commutator 3 and a core 4 around which a coil is wound around a rotary shaft 2, is placed in a lower die 12.
The rotating shaft 2 and the commutator 3 at both ends of the recess 14
b and 15b, respectively, and set so that the core 4 at the center thereof is accommodated in the cavity recess 13b. Subsequently, when the upper mold 11 is fitted onto the lower mold 12 and the molds are clamped, the core 4 is inserted into the cavity 1.
3 and is housed in an appropriately positioned state.

A desired resin, such as, for example, an epoxy resin, is then brought into a fluid state from the resin supply to the runners 18A, 181.
3, the resin passes through the first gates 16A, 16B and the second gate 1 arranged on both sides of the armature 4.
The cavities 13 are filled from 7A, 17B, respectively. When the resin is cured after the pre-arrangement is completed, a resin package 5 is formed around the outer periphery of the core 4 into a substantially circular shape.

Thereafter, the mold is opened, the molded product is released, and the molded sides of the gate and runner are cut off. When the surface of the molded resin package 5 is subjected to a grinding process, a motor rotor with a clean surface, extremely low viscous resistance, and gasoline resistance is obtained.

By the way, if the opening areas of the first gate and the second gate are set equal to each other, at the initial stage of resin filling,
Since the filling speed from the first gate located on the upstream side is faster than the second gate located on the downstream side, the pushing forces acting on the core from both sides in the axial direction become unbalanced, and the core A phenomenon occurs in which the top is moved toward the second gate.

This phenomenon tends to occur when the armature coil has a high space factor. In other words, the cavity is separated into both sides in the axial direction by the armature, and both sides are communicated by the slot, and the resin flows through the slot and fills the entire cavity, but the space factor of the coil is This is because if it is high, the gap becomes narrow and the flow resistance acting on the resin also becomes large.

However, in this embodiment, the second gate 17A.

Since the opening area of gate 17B is set larger than that of first gates 16A and 16B, even though the second gate is located downstream of the first gate with respect to the flow of filled resin, the resin At the initial stage of filling, the filling speeds of the first gate and the second gate are the same, and as a result, the core 4 is not moved on the rotating shaft 2 toward the second gate.

That is, if the filling speeds of the first gate and the second gate are the same from the beginning of filling the M fat into the cavity 13,
Since the resin is evenly filled from the beginning on both sides of the core 4 in the cavity 13, the pushing forces acting on the core 4 from both sides in the axial direction are balanced and cancel each other out. As a result, even if the core 4 is mounted on the rotary shaft 2 so that it can be easily moved, it will not be moved accidentally.

This prevention of movement is achieved by balancing the acting forces on both sides of the core 4 (1'l), so even if the space factor of the armature coil increases, the slot becomes narrower, and the resin distribution efficiency decreases. , would be similarly prevented.

According to the embodiment described above, the following effects can be obtained.

(1) By forming the second gate located on the downstream side with respect to the flow of the resin so that its opening area is larger than the opening area of the first gate located on the upstream side, the cavity can be Since the filling speeds of the first gate and the second gate can be maintained at substantially the same rate from the initial stage of resin filling, it is possible to prevent unexpected movement of the core on the rotation axis.

(2) By preventing the core from moving relative to the rotation axis, there is no need to excessively strengthen the positive force of the core to the rotation axis, which simplifies processing and improves core installation accuracy. Since it is possible to maintain a high temperature, the quality of the rotor can be improved.

(3) Since movement of the rotor with a high space factor of the armature coil can be effectively prevented, the space factor of the coil can be increased and the performance of the motor can be improved.

(4) By adjusting the correlation between the opening areas of the second gate and the first gate, the filling speed of the resin can be set to be substantially equal, so that the modification of the installation A+1 can be kept to a minimum.

Note that the present invention is not limited to the above embodiments,
It goes without saying that various changes can be made without departing from the gist of the invention.

For example, means for making the resin filling speeds for both gates approximately equal are not limited to a structure that mutually adjusts the opening areas of both gates, but also a structure that mutually adjusts the lengths of both gates, and a structure that mutually adjusts the lengths of both gates. A conceivable structure is to connect launches to the runners and adjust the lengths of the runners to be equal.

In the above embodiments, a rotor used in a motor that is immersed in fuel is molded, but the present invention is applicable not only to rotors used in other types of motors, but also to rotors other than motors, such as rotors of generators, etc. It can also be applied when molding.

〔Effect of the invention〕

As explained above, according to the present invention, by maintaining substantially the same filling speed at the gates on both sides of the core from the initial stage of resin filling into the cavity, the pushing forces acting on the core from both sides can be balanced with each other. Because it is possible to
Movement of the core within the cavity can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a plan sectional view showing a rotor resin molding method according to an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the molded rotor, and Fig. 3 shows a molding device used therein. It is an exploded perspective view. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Rotating shaft, 3... Commietator, 4... Core, 5... Resin package, 10...
... Molding device, 11... Upper mold, 12... Lower mold, 13
...Cavity, 13a, 13b...-Recess, 14
a, 14b--rotating shaft holding recess, +52.15b...
・Commutator holding recess, 16A, 16B...first
Gate, +7A, 17B...Second gate, 18A, 1
8B...Runner. Agent Patent Attorney Tatsu Kajihara Figure 1 + SS Figure 2

Claims (2)

[Claims] (1) A resin molding method for a rotor having a resin package outside the armature, in which resin is filled into a cavity in which the armature is housed through gates arranged on both sides of the core. A rotor resin molding method, characterized in that resin filling speeds at both gates are set to be substantially the same speed at an initial stage of resin filling. (2) The rotor resin molding method according to claim 1, wherein the opening area of the downstream gate is set larger than the opening area of the upstream gate.