JPH048899A - Cooling device for electric motor - Google Patents

Abstract

PURPOSE:To enhance a cooling effect for an electric motor by fitting a cooling fan to the motor shaft of the electric motor via a one-way clutch to engage with the cooling fan during the rotation of the motor shaft, and disengage therefrom when the motor shaft is at rest, and keeping the continuous rotation of the cooling fan even after the motor shaft stops. CONSTITUTION:When an electric motor is driven, the pin 10 of a motor shaft 4 rotates via engagement with the stepped section 13 of a cooling fan 6. The cooling fan 5, therefore, rotates integrally with the motor shaft 4, and heat within the motor is dissipated outside through the opening 3 of an end plate 2, thereby cooling the motor. On the other hand, when the motor shaft 4 is at rest, the cooling fan 6 rotates on inertia, while the pin 10 is being pressed into a lateral hole 9 with the wall surface of a flank hole 12. Namely, the cooling fan 6 continues to rotate on inertia, even after the motor shaft 4 stops, and the electric motor is thereby cooled. More particularly, the cooling fan 6 is fitted to the motor shaft 4 via a bearing 7, and made to follow the rotation of the motor shaft 4 via a one way clutch 8.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling device for an electric motor used as a drive motor of an industrial vehicle such as a battery-powered forklift.

(Prior Art) FIG. 4 shows a cooling device for an electric motor as a drive motor used in a conventional battery-powered forklift. As shown in the figure, a cooling fan 22 is fixed to the end of the motor shaft 21, and when the electric motor is driven, the cooling fan 22 rotates together with the motor shaft 21 to blow hot air inside the motor through the opening of the end plate 23 as shown by the arrow in the figure. It has a structure that releases it from 24 to the outside. Incidentally, as a technique related to such a cooling device, for example, Japanese Utility Model Application Publication No. 1988-95200 can be mentioned.

(Problem to be Solved by the Invention) In the conventional device described above, either the cooling fan 22 or the motor shaft 21
Since it has a fixed structure, when the motor shaft 21 stops, the cooling fan 22 also stops at the same time.

However, since the electric motor generates a considerable amount of heat after it has stopped rotating, it is not actually desirable to stop the cooling action at the same time as the electric motor stops rotating. If this is repeated frequently, the electric motor will be driven intermittently, making it impossible to obtain an effective cooling effect and potentially causing the electric motor to overheat.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention aims to provide an improved electric motor cooling device that continues its cooling effect not only while the electric motor is rotating, but also for a while after the rotation has stopped. That purpose.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a cooling fan on the motor shaft of an electric motor, engages with the cooling fan when the motor shaft rotates, and engages the cooling fan when the motor shaft stops. It is configured to be attached via a one-way clutch that is released and released.

(Function) According to the above means, when the motor shaft rotates, the cooling fan rotates together with the motor shaft via the one-way clutch to perform the cooling action, and when the motor shaft is stopped, it rotates due to inertia and performs the cooling action. continue.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 to 3.

In the figure, 1 is the electric motor housing, and 2 is the housing ■
It is an end plate fixed to one end of the end plate, and is provided with a plurality of heat radiation openings 3 at appropriate intervals in the circumferential direction. A motor shaft 4 is rotatably attached to the end plate 2 via a bearing 5, and its end protrudes from the end plate 2, and a cooling fan 6 is attached to the protruding end.

Specifically, the cooling fan 6 connects to the motor shaft 4 via a bearing 7.
The motor shaft 4 is attached to the motor shaft 4 and rotates following the motor shaft 4 via a one-way clutch 8. That is, as shown in FIG. 3, a horizontal hole 9 is formed in the motor shaft 4 and extends through the motor shaft 4 in the radial direction, and pins 10 are slidably inserted into the horizontal hole 9 from both sides. Both pins 10 are always urged in the projecting direction by a spring 11 in the horizontal hole 9, and are locked in a stepped portion 13 of a relief hole 12 formed in the boss portion 6a of the cooling fan 6. . Therefore, regarding the rotation in the locking direction, the torque of the motor shaft 4 is transmitted from the pin 10 to the cooling fan 6 via the stepped portion 13, but regarding the rotation in the unlocking direction, the torque of the motor shaft 4 is transmitted to the wall of the relief hole 12 of the cooling fan 6. The pin 10 is pushed and the horizontal hole 9
This allows the cooling fan 6 to rotate relative to the motor shaft 4.

The cooling device of this embodiment is constructed as described above, and therefore, when the electric motor is driven, it is rotated by being engaged with the pin 10 of the motor shaft 4 or the stepped portion 13 of the cooling fan 6 as described above. The cooling fan 6 rotates together with the motor shaft 4, and cools the motor by discharging the hot air inside the motor to the outside through the opening 3 of the end plate 2, as shown by the arrow in FIG.

Thus, when the motor shaft 4 is stopped, the cooling fan 6 rotates by inertia while pushing the pin 10 into the horizontal hole 9 by the wall surface of the escape hole 12. In other words, the cooling fan 6 continues to rotate due to inertia even after the motor shaft 4 has stopped, and can cool the electric motor. At this time, the pin 10 repeatedly moves in and out of the horizontal hole 9. Become.

Therefore, if the electric motor is started intermittently in cases such as a forklift truck that repeatedly starts and stops, the electric motor will be started intermittently, but if the time between stopping and restarting the electric motor is short, cooling The fan 6 essentially rotates continuously, and a certain amount of weight is required for the rotation of the cooling fan 6 due to inertia to obtain an effective cooling effect.In that sense, the cooling fan 6 is It is desirable to set it slightly heavier than the previous one.

Note that the one-way clutch 8 using the pin 10 shown in this embodiment is just one form, and can be modified as necessary. In short, motor shaft 4
Any configuration may be used as long as it transmits torque to the cooling fan 6 when the motor shaft 4 rotates, and allows the cooling fan 6 to rotate freely when the motor shaft 4 stops.

(Effects of the Invention) As detailed above, according to the present invention, the cooling fan for cooling the electric motor can continue to rotate even after the motor shaft has stopped, so the cooling effect of the electric motor is enhanced. Lifespan will be extended. Further, since the present invention uses inertia to continuously rotate the cooling fan, it does not require a special drive device.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a plan sectional view showing a one-way clutch, and FIG. 4 is a longitudinal sectional view showing a conventional example. 1... Motor shaft 6... Cooling fan 8... One-way clutch Applicant Toyota Industries Corporation Representative Patent attorney Hidehiko Okada (3 others) 1... Motor shaft 6... Cooling fan one-way clutch

Claims (1)

[Claims] An electric motor cooling device in which a cooling fan is attached to the motor shaft of an electric motor via a one-way clutch that engages with the cooling fan when the motor shaft rotates and disengages from the cooling fan when the motor shaft stops.