JPH0314929Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an electric motor, particularly to an improvement in the fixing structure between the stator and the casing.

[Conventional technology]

In order to minimize loss (so-called iron loss) due to eddy currents and magnetic history that occur during operation, the stator of the electric motor is made of thin sheets of silicon steel concentrically.
Annular plates each having a predetermined slot on the outer circumferential surface are punched out using a punching press, and then a predetermined number of the punched annular plates are stacked so that the outer circumferential surface and the slots are perfectly aligned, and the thus laminated annular plates are then stacked together. The core is generally used as an integral hollow cylindrical core by welding the slots on the outer circumferential surface of the core in a well-adhered state using a pressure press. In the case of specialized electric motors for driving actuators such as valves, prescribed windings are housed in slots on the inner peripheral surface of the hollow cylindrical core formed as described above to form a stator. In many cases, the product is inserted and fixed into the casing manufactured by the OEM.

In this case, the method of fitting and fixing the stator into the casing is to press fit or shrink fit for small size stators, and for large size stators, the method is to fit the stator into the casing using one of the slots on the outer circumferential surface of the stator. A key groove corresponding to the stator is provided on the inner peripheral surface of the casing, and the stator is fixed by inserting a key plate into the key groove and the slot, or the stator is fixed at a symmetrical position with respect to its center line on the outer peripheral surface of the stator. The conventional method of fixing is to provide a boss in the casing with through-tap holes drilled therein corresponding to the slots occupying the stator, screw a push bolt into each through-tap hole, and press the stator slot with the lower end of the boss. It had been taken.

However, with conventional methods for small-sized products, such as press-fitting or shrink-fitting, when the actuator is used in a high-temperature atmosphere for a long time, the casing expands and the tightness between the stator and the actuator expands. As a result, it was not possible to completely prevent slippage between the two due to shock-like torque acting on the stator at the time of starting.

In addition, in the conventional key locking method for large items, a keyway must be machined on the inner circumferential surface of the casing, but this may vary depending on the shape of the casing. The other method, which uses locking bolts, requires a considerable amount of man-hours to process, and the starting torque that acts on the stator acts intensively on the tap holes and slots, resulting in a long period of time. If fatigue failure has occurred in the casing or stator due to repeated stress concentration during use, and if the location of use requires the motor to be explosion-proof, The tap hole had to be sealed by welding or the like.

[Problem that the invention attempts to solve]

In this way, in electric motors, especially electric motors for driving actuators such as valves, which are used in special environments, there are no methods other than the conventional key locking method for fitting and fixing the stator into the casing. It is not possible to completely prevent slippage between the stator and casing or fatigue damage during long-term use, and the method of fixing both the stator and casing with a key, regardless of the size, Although there is no risk of slippage or breakage as described above, a problem with conventional methods is that a new keyway must be provided in the casing, which requires a considerable amount of man-hours depending on the shape of the casing. It is a point.

This idea was created in view of the current situation mentioned above, due to the large size,
The purpose of the present invention is to provide an electric motor with a fixed structure between the stator and casing, which can be easily fixed as securely as a key lock without any new processing on both the stator and the casing, regardless of the size. That is.

[Means for solving problems]

In this invention, as a technical means for solving the above-mentioned problems, an electric motor is configured as follows. That is, at least one of the slots provided on the outer periphery of the stator as a guide groove or welding groove when forming the stator core is made of a harder material than the casing into which the stator is incorporated, and when the stator is press-fitted, the casing A key-shaped member having a ridge portion for cutting a groove in which a part of the stator is accommodated is housed in the inner wall surface of the stator, and the stator is press-fitted into the casing together with the key-shaped member.

[Effect]

Since the electric motor according to this invention is constructed as described above, when the stator is press-fitted into the casing, the key-shaped member housed in at least one of the slots on the outer circumferential surface of the stator is inserted into the casing. By cutting a groove in the wall to accommodate the stator, the stator can be inserted between the stator and the casing without having to process the casing in advance. A rotation prevention effect is provided, and the stator can be fixed to the casing.

〔Example〕

Hereinafter, an embodiment of the device according to the invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing the configuration of the main parts of this embodiment device. However, the stator shown on the left side is drawn without the windings housed in slots in its inner peripheral surface.

As mentioned above, the stator 1 is made by punching annular plates having slots equally distributed on the inner and outer circumferential surfaces of the concentric surfaces from a thin silicon steel plate as described above, and then punching out a predetermined number of annular plates so that the outer circumferential surfaces and the slots are perfectly aligned. They are superimposed and pressed together sufficiently by pressing. [The slot 2 on the outer circumferential surface is used as a guide groove when superimposed, and is used as a welding groove in the above-mentioned state of close contact. ] A hollow cylindrical core is formed by welding the center of the bottom of the slot 2, and the winding wire is wound as specified into the slots 3, which are evenly distributed on the inner peripheral surface of this core. (not shown).

Casing 4 in which this stator 1 is incorporated
is formed, for example, from an AC4C aluminum alloy casting, and the inner wall surface 5 in which the stator 1 is assembled, the flange surface 6 to which the electric motor is attached, etc. are machined.

Hole 5 of casing 4 finished in this way
The inner diameter dimension of the hollow cylindrical stator 1 and the outer diameter dimension of the hollow cylindrical stator 1 are not tightly fitted but have an intermediate fit relationship.

What is shown in FIG. 2 is that when the stator 1 having the above-mentioned dimensional relationship is press-fitted into the hole 5 of the casing 4, the slot 2 on the outer peripheral surface of the stator 1 is inserted into the hole 5 of the casing 4.
This is a part of a key-shaped member 7 that is press-fitted into the casing 4 together with the stator 1 and serves as a lock for fixing the stator 1 to the casing 4.

The key-shaped member 7 is made of a drawn bar of carbon tool steel (SK6), which is harder than the material of the casing 4 (AC4C aluminum alloy casting in this embodiment), and has a triangular cross-sectional shape. be. The width B of the bottom surface is smaller than the width of the slot 2, and the height H thereof is slightly higher than the depth at the center of the width of the slot 2.

The key-like member 7 is inserted into the slot 2 as shown in FIG.
[This slot is not welded,
Or fillet welding is applied, and the key-shaped member 7
The tip of the key-shaped member 7, which will be press-fitted into the casing 4 first, should be press-fitted by welding a locking piece or by bending it. Set up a hook that will not slip over time.

In addition, it is easier to work if a part is provided to guide the press-fitting at the start of press-fitting. Therefore, near the tip of the key-shaped member 7, it is recommended that the ridge part be slightly set aside along with the outer peripheral surface of the core so that a cutting edge angle is formed. .

Now, when the key-shaped member 7 is housed in the slot 2 in this way without causing any displacement and is press-fitted into the hole 5 of the casing 4 together with the stator 1,
The ridge of the key-shaped member 7 that protrudes from the slot 2 is connected to the inner wall surface 5 of the casing 4, which has a lower hardness than the ridge of the key-shaped member 7.
Since a groove with a triangular cross section is cut to accommodate a part of the key-shaped member 7 between the stator 1 and the casing 4, no new grooves are formed in the inner wall surface 5 of the casing 4. Both can be easily and reliably intervened.

The stator 1 is completely fixed to the casing 4 so that the stator 1 does not slip between the stator 1 and the casing 4 due to the torque acting as a reaction on the stator 1 during operation of the electric motor.

Note that the key-shaped member 7 is not limited to a triangular cross-sectional shape, and may be any member having a cutting ridge.

〔effect〕

In the electric motor according to this invention, regardless of the size, the stator can be easily and securely fixed to the casing in the same way as conventional key fastening without any new processing on both the stator and the casing. This makes it possible to reduce costs while eliminating any slippage or damage that occurs between the stator and casing during long-term use, and it can also be easily adapted to cases where an explosion-proof type is required.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the configuration of the main parts of an electric motor according to an embodiment of the invention, and FIG. 2 is a partial perspective view of a key-shaped member. 1... Stator, 2... Slot, 3... Slot, 4... Casing, 5... Hole (inner wall surface),
7...Key-shaped member.

Claims (1)

[Scope of utility model registration request] At least one of the slots provided on the outer periphery of the stator as a guide groove or a welding groove when forming the stator core is made of a harder material than the casing in which the stator is incorporated, and when the stator is press-fitted, the slot is made of a harder material than the casing's inner wall surface. An electric motor comprising a key-shaped member having a ridge for cutting a groove, and a stator press-fitted into a casing together with the key-shaped member.