JP2853810B2 - Electric motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor having a structure in which a bearing for supporting a rotating shaft is held by at least one of a housing and a bracket.

[Prior Art and Problems to be Solved by the Invention] Conventionally, there has been known a molded electric motor which is small and excellent in integration and mass productivity. This mold type electric motor usually has a stator core, and a winding wound around the stator core,
A housing in which the stator core and the entire winding are integrally molded using a molding material containing a resin, a pair of brackets provided on both sides of the housing, and a predetermined gap with the stator core are provided. Rotor and
It comprises a rotating shaft to which the rotor is attached, and a pair of bearings for supporting the rotating shaft.

On the other hand, in a molded motor, a ball bearing is generally widely used as a bearing for rotatably supporting a rotating shaft, and this bearing is integrally held by a fitting portion of a housing or a bracket. However,
Since the rotating shaft and bearing vibrate with the rotation of the rotating shaft,
The low-strength fitting portion of the housing or the bracket is polished, causing play with the outer ring of the bearing. Moreover,
If the rotating shaft rattles due to play between the bearing and the housing or the bracket, the gap between the stator and the rotor is so small that the rotor cannot rotate and cannot function as an electric motor.

Therefore, conventionally, in order to hold the bearing at the fitting portion of the bracket while preventing the rotation of the bearing outer ring, a knurled fitting portion is formed by cutting out mild steel of the bracket, or the bracket is eccentrically formed by iron plate drawing. Processing and eccentric arrangement of the bearing are performed.

However, in these cases, shaving of mild steel or drawing of iron plate generates shavings and slag, and wastes material. Moreover, knurling and eccentric machining require complicated operations. In particular, in these methods, it is necessary to perform knurling or eccentric processing for each bracket, which complicates the operation and reduces productivity.

On the other hand, as a method of reinforcing the fitting portion of the bearing of the housing or the bracket, in a state where the reinforcing material is fixed to the outer periphery of the bearing, forming the housing by molding,
It is conceivable to form the bracket by casting. Further, as a method of fixing the reinforcing material to the bearing, a method of fixing the reinforcing material to the bearing using a magnetic attraction force of a magnet or pressing the bearing with a mold or a casting mold is also conceivable. However, in the former fixing method, when the bracket is formed by casting in a state where the magnet is attracted to the bearing via the reinforcing material, the magnet and the reinforcing material are axially moved by the flow pressure of the molten metal injected from the gate. The movement makes it difficult to position the reinforcement. In the latter fixing method, it is necessary to press the bearing with a mold or the like while positioning the bearing each time one electric motor is produced. Therefore, these methods are not only impractical, but also reduce the productivity of the motor and increase the cost.

Accordingly, an object of the present invention is to provide an electric motor having a structure in which a rotating shaft is supported by a bearing held by a housing or a bracket, without waste of material, enabling a reinforcing material to be easily and reliably fixed to the bearing, and forming the bearing. Can be fixed to the mold,
In addition, it is an object of the present invention to provide an electric motor capable of reinforcing a housing and a bracket and securing a gap between a stator core and a rotor for a long period of time.

[Means for Solving the Problems] The present invention relates to a housing for integrating a stator core and a winding, a bracket attached to both sides of the housing, and a rotor rotatable relative to the stator core. In an electric motor having a rotating shaft to which is attached, and a bearing that supports the rotating shaft and is held by the housing or the bracket, an elastic helical wire is attached to a mounting portion of the mold in the bearing. In the state, the housing or bracket is formed by molding or casting, and the helical wire is buried in the housing or bracket by an electric motor,
This is to solve the above-mentioned problem.

[Operation] According to the present invention, the helical wire can be fixed to the mounting portion of the bearing by using the contraction force of the elastic helical wire mounted on the outer periphery of the bearing. Further, when the housing is formed by molding or the bracket is formed by casting, the spiral wire can be fixed to the mold or the casting mold by utilizing the spring action.

In addition, when the spiral wire is mounted, the spiral wire is cut into a predetermined length, and the spiral wire can be mounted not only on the mounting portion corresponding to the outer periphery of the bearing, but also the diameter of the spiral wire can be changed. Even a plurality of bearings having different sizes can be fixed with one spiral wire. Therefore, a spiral wire made of one wire can be used effectively, and there is no waste of material.

Furthermore, even if the bearing vibrates with the rotation of the rotating shaft, the spiral wire is interposed between the bearing and the housing or the bracket, so that it is possible to prevent the vibration force from directly acting on the housing or the bracket and to embed it. The housing and the bracket can be reinforced by the spiral wire thus formed.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a schematic partial sectional view showing one embodiment of the present invention,
FIG. 2 is an exploded perspective view of a main part of the embodiment shown in FIG.
This motor comprises a stator core (1), a winding (2) wound around the stator core (1), and a housing (1) that integrates the entire stator core (1) and the winding (2). 3). The housing (3) is formed by molding using a molding material containing a synthetic resin.

A rotary shaft (4) is disposed in the housing (3), and the rotary shaft (4) is rotatable relative to the stator core (1) with a predetermined gap. (5) is integrally mounted. The rotating shaft (4)
Is rotatably supported by a pair of ball bearings (6a) (6b).

A pair of brackets (7a) (7b) are attached to both sides of the housing (3). Of the pair of brackets (7a) (7b), one of the brackets (7a) is fixed to the housing (3) in a pair with its peripheral edge buried in the housing (3). The other bracket (7b) is integrally fixed to the housing (3) by screwing a screwing member (9) to a hollow cylindrical filling metal (8) embedded in the housing (3). I have.

In this example, the pair of ball bearings (6a)
One of the ball bearings (6a) of (6b) is held in the housing (3) in a molded state,
The other bearing (6b) is fitted and held by the fitting part of the bracket (7b).

Then, in order to reinforce the housing (3) having a smaller mechanical strength than the brackets (7a) and (7b), a helical wire rod (10) having elasticity is mounted on a mounting portion on the outer periphery of the ball bearing (6a), And it is embedded in the housing (3).

With this configuration, even if the rotating shaft (4) and the ball bearing (6a) vibrate with the rotation of the rotating shaft (4), the spiral wire ( According to 10), the vibration force of the ball bearing (6a) can be prevented from directly acting on the housing (3). Further, since the spiral wire (10) is mounted on the outer periphery of the ball bearing (6a), the mounting portion of the housing (3) where the ball bearing (6a) is mounted can be reinforced, and the mechanical strength can be increased. . Therefore, the housing (3)
Of the ball bearing (6a) can be prevented from being worn, and a minute clearance formed between the rotor (5) and the stator core (1) can be secured for a long time. Further, the spiral wire (10) can be easily and reliably fixed to the mounting portion of the mold where the ball bearing (6a) is mounted, by utilizing the contraction force of the spiral wire (10). Therefore, the housing (3) can be easily formed by molding with the spiral wire (10) fixed in the forming die. Furthermore, one spiral wire (10) is cut to the required length,
Since it is sufficient to mount the wire on the mounting portion corresponding to the outer periphery of the ball bearing (6a), unlike the conventional machining of mild steel, all the wires (10) can be used effectively and there is no waste of material.

FIG. 3 is a schematic sectional view showing another embodiment of the present invention. The same members as those of the electric motor shown in FIGS. 1 and 2 are denoted by the same reference numerals and described.

In this example, the spiral wire (10) is mounted on the outer peripheral surface of one of the pair of ball bearings (6a) (6b). The spiral wire (10) is embedded in a fitting portion of the bracket (17a) (17b) provided on both sides of the housing (3) with the one ball bearing (6a). . In addition,
The bracket (17a) embedded with the spiral wire (10)
Is formed by casting a light alloy such as an aluminum or zinc alloy.

One of the brackets (17a) of the pair of brackets (17a) (17b) has a stator core (1) and a winding (3).
Is integrated with the housing (3) to be integrated,
The other bracket (17b) is integrated with the housing (3) by a hollow cylindrical filler metal (8) and a screw member (9), as in the previous embodiment. The rotor (5) attached to the rotating shaft (4) is rotatable relative to the stator core (1).

In this example as well, as in the previous embodiment, the spiral wire (10)
Can be securely fixed to the mounting position of the ball bearing (6a) in the mold, the fitting part of the bracket (17a) can be reinforced, and the vibration of the ball bearing (6a) allows the fitting part of the bracket (17a). And the like can be prevented from being worn.

Note that the helical wire only needs to have spring elasticity,
It can be formed of a material having better wear resistance and strength than the material of the applied housing or bracket, for example, a mild steel wire. The cross-sectional shape of the spiral wire is not particularly limited, and may be cylindrical, planar, or polygonal.

The housing may be formed not only of a synthetic resin such as a thermosetting resin, but also of a molding material in which the resin is filled with an inorganic filler.

The bracket is not limited to the screw member and the like, and may be attached to the housing by a conventional coupling means such as a fitting means. The bearing is not particularly limited as long as the bearing rotatably supports the rotating shaft.

The present invention is not limited to the internal rotation type, and can be applied to, for example, an external rotation type motor.

[Effects of the Invention] As described above, according to the present invention, a spiral wire having elasticity may be cut into a predetermined length and mounted on a portion corresponding to the outer periphery of the bearing, so that there is no waste of material. The helical wire can be simply and reliably fixed to the mounting portion of the bearing, and can be fixed to the molding die. Also, since the spiral wire is embedded in the housing or bracket on the outer periphery of the bearing,
The housing and the bracket can be reinforced, and the gap between the stator core and the rotor can be secured for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view showing one embodiment of the present invention, FIG. 2 is an exploded perspective view of a main part of the embodiment shown in FIG. 1, and FIG. 3 is a schematic showing another embodiment of the present invention. It is sectional drawing. (1) ... stator core, (2) ... winding, (3) ... housing, (4) ... rotating shaft, (6a) (6b) ... bearing, (7a) (7b) (17a) ) (17b)… bracket, (10)… spiral wire

Claims (1)

(57) [Claims] 1. A housing for integrating a stator core and a winding, a bracket mounted on both sides of the housing, a rotating shaft having a rotor rotatable relative to the stator core mounted thereon, In the electric motor having the bearing supported by the housing or the bracket while supporting the rotating shaft, the elastic helical wire is molded or cast in a state where the elastic helical wire is mounted on the bearing mounting portion of the mold. The electric motor is characterized in that the housing or the bracket is formed by doing so, and the spiral wire is embedded in the housing or the bracket.