JPH043580Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to the structure of a clutch portion of a small electric motor.

Prior Art For example, Japanese Utility Model Application No. 50-63114 discloses a small electric motor with a clutch having the same function as the present invention. The idea is to incorporate a clutch in the middle of transmitting the rotation of the rotor to the output side through a gear train, and to control the engagement and disengagement of the clutch by moving one clutch member of the clutch in the thrust direction. There is.

Usually, such a clutch member is constructed as a part of a gear and is manufactured by plastic molding, so the surface accuracy of the part, especially the tooth surface, is poor compared to other parts. ing. Moreover, when the modulus is as small as about 0.4, polishing cannot be performed on that part of the tooth surface, so there is a limit to the smoothness of the tooth surface.

If there is a sliding movement between these poorly finished tooth surfaces in connection with the engagement and disengagement of the clutch, the rotational force in the return direction is constantly acting on the load section on the output side, that is, the clutch section If reverse torque is applied to the clutch, it becomes difficult for one member of the clutch to move in the thrust direction, and there is a risk that the clutches will bite into each other.

Furthermore, in the above-mentioned invention, one of the clutch members is provided so as to be movable in the thrust direction, and is always urged in the direction of separation by a coil spring, but the clutch teeth are in the shape of sawtooth. Therefore, a large amount of elasticity is required in the coil spring to release the clutch. As a result, when the clutch member is pulled apart, the clutch member is frictionally pressed against the base plate portion due to its elasticity, and a resistance force is generated in that portion. For this reason, when the load to be driven, such as a ventilation fan shutter, is always biased in the return direction, and the small electric motor with a clutch operates in the closing direction while reversing the gear train,
Since frictional force is generated between the clutch member and the base plate, this becomes a braking force, and even when the clutch is disengaged, the ventilation fan shutter on the load side becomes difficult to move in the closing direction due to the urging force of the accident. . In particular, the winding load of the ventilation fan shutter is
The reversal torque of the output shaft must be small in design, since it is not constant and therefore the return force of the shutter when the clutch is disengaged is also not constant.

In this way, in conventional small electric motors with clutches, the shape of the meshing teeth of the clutch member, the meshing resistance with the gear train due to the sliding of one clutch member in the axial direction, and the relationship between the clutch member and other members after movement are known. The frictional braking force and other factors have a large effect on the desired operation of the load.

Purpose of the invention Therefore, the purpose of the invention is to prevent the engaging teeth from biting into each other at the initial stage of clutch disengagement, and also to enable reverse torque of the disengagement side clutch member and the gear train meshing with it when the clutch is disengaged. The goal is to reduce it as much as possible.

Therefore, the present invention sets the face angle of at least one of the engaging teeth of the clutch to 10 degrees or more, preferably about 35 degrees with respect to the axial direction, and also sets the face angle of at least one of the engaging teeth of the clutch to 10 degrees or more, preferably about 35 degrees. The face angle of one of the engaging teeth is made larger than the face angle of the other engaging tooth, so that the reversal torque from the load side generates a component force in the direction of separating the engaging teeth from each other. Does the force assist the pulling action of the spring?
Alternatively, the spring can be omitted.
As a result, the spring does not require a large disengagement force, so that the sliding resistance between one clutch member and the other receiving member can be reduced.

In addition, the present invention has an embodiment shown below, in which teeth are not directly formed on the disengagement side clutch member, but a gear train on the output side is provided with a gear that is movable in the axial direction with respect to the clutch member and transmits only rotational force. The rotation is transmitted to the Therefore, even if one clutch member slides in the axial direction, it will no longer slide on the tooth surfaces of the gear train, so the engagement and disengagement of the clutch will not affect the finish of the tooth surfaces, as in the past. It will no longer be done.

Structure of the invention FIG. 1 shows a small electric motor 1 with a clutch according to the invention. This small electric motor 1 with a clutch is built into a casing 2, and its rotor 3 is rotated by a rotating shaft 5 at the center of pole teeth 4 formed by a part of the casing 2. freely supported. The pinion 6, which is integral with the rotating shaft 5, is engaged with the first gear 7. This first gear 7 is rotatably supported at a boss 7a with respect to an intermediate shaft 8 fixed to the casing 2, and is frictionally engaged with a reverse prevention lever 9 at this boss 7a. It's on. The anti-reverse lever 9 receives a frictional rotational force from the first gear 7, and when the rotor 3 rotates in the opposite direction, the anti-reverse lever 9 hits the anti-reverse pawl 10 formed integrally with the pinion 6. An impact force in the normal rotation direction is applied to the rotor 3, and the rotor 3 is restricted to rotate in the normal rotation direction at an early stage of reverse rotation.

According to this embodiment, the first gear 7 also serves as the clutch member 11 on one side, and the engagement teeth 11a formed on one surface engage the clutch member 12 on the disengagement side. It faces the tooth 12a. Moreover, at least one of the engaging teeth 11a, for example, is formed so that its apex angle is obtuse, as shown in FIG. 2, and its face angle α is 10 degrees or more, 35 degrees in this embodiment. is set to . Further, the other face angle β is set to 5 degrees as an example in this embodiment, as shown in FIG.

The clutch member 12 is inserted into the intermediate shaft 8 so as to be rotatable and slidable in the axial direction, and is engaged by a coil spring 14 provided between the clutch member 11 and the clutch member 11. It is always urged in a direction away from the member 11, and further faces the operating member 15 at the hollow shaft 12b at the tip. Note that this operating member 15
is connected to the plunger 16, and by reciprocating in the direction of the arrow, the clutch member 1
Controls the meshing of parts 1 and 12.

Further, this clutch member 12 is connected to a second gear 17.
is inserted inside. That is, this second gear 17 transmits rotation to the output side gear 18, and the boss 17a of the second gear 17 engages the casing 2.
It is rotatably supported in a state concentric with the intermediate shaft 8 with respect to the bearing part 2a. Note that the intermediate shaft 8
is fixed to the casing 2 only on one side, but is also indirectly supported by the bearing part 2a of the other casing 2 by the hollow shaft 12b of the clutch member 12 and the boss 17a of the second gear 17. This means that Note that the hole in the hollow shaft 12b of the clutch member 12 is set to be larger than the outer diameter of the intermediate shaft 8, except for the end on the coil spring 14 side, so that even if the clutch member 12 is tilted with respect to the hollow shaft 8, , the bearing part 12a and the boss 17a of the second gear 17
Care has been taken to prevent prying from occurring between the parts.

The second gear 17 is adapted to rotate together with the clutch member 12 by fitting into an engaging hole 12c formed in the clutch member 12 at a portion of the engaging pawl 17b formed integrally with the second gear 17.
These engagement holes 12c and engagement claws 17b constitute engagement means. In addition, the casing 2 is
It is fixed to a mounting plate 13 or the like.

Effect of the invention When the small electric motor 1 with a clutch is connected to a power source, the rotor 3 rotates, and its rotational force is transmitted to the first gear 7 while being decelerated by the pinion 6. At the same time, the plunger 16 operates, and the operating member 15 presses the hollow shaft 12b.
The engaging tooth 12a of the clutch member 12 is pressed against the engaging tooth 11a against the elasticity of the coil spring 14. At this time, the engaging teeth 11a and 12a are mutually
Because of the meshing, the rotational force of the first gear 7 is transmitted to the clutch member 12, and further transmitted to the output side gear 18 via the second gear 17 by the engaging pawl 17b.

Now, assuming that the load of this small electric motor 1 with a clutch is a ventilation fan shutter, for example, when the shutter is released, the power of the small electric motor 1 with a clutch is turned off by the cam mechanism at that position. set to state. In this released state, the shutter is always biased in the closing direction, but
The force in the closing direction is applied to gear 18, second gear 1
7. A certain amount of holding torque is transmitted to the clutch members 11 and 12 even when the rotor 3 is de-energized, so the shutter is not released even though it is biased in the closing direction. It remains in its current state.

Next, when closing the shutter, the power to the plunger 16 is turned off. At this time, the clutch member 12 receives the elastic force of the coil spring 14 and is urged away from the corresponding clutch member 11 while being guided by the intermediate shaft 8. At the same time, a reversing torque acts on the clutch member 12 in response to the restoring force of the shutter on the load side.
1a and 12a act as component forces in the thrust direction, that is, in the direction away from each other, so that one clutch member 12 separates from the clutch member 11 and moves the second gear 17 and gear 18 on the driven side to the second gear 17 on the driving side. 1 Separate from gear 7. At this point of separation,
Since the holding torque of the rotor 3 no longer acts on the second gear 17, the second gear 17 and the output side gear 18
, the clutch members 11 and 12 can be rotated with a lighter reverse torque than when they are engaged. As a result, the shutter as a load is forced to close the second gear 17 on the driven side by its own biasing force in the closing direction.
Then, the gear 18 is rapidly reversed and returned to the closing direction.

Of course, when the engaging teeth 11a and 12a are separated, the tooth surfaces are not formed in a sawtooth shape unlike the conventional ones, and the clutch member 12 can be separated with a light force, so the coil spring 12 , a relatively small elasticity is sufficient, and there is no risk of the clutch members 11, 12 jamming.

In this embodiment, the clutch member 12 and the second gear 17 are constructed as separate members, and the second gear 17 does not move in the axial direction when the clutch member 12 is disengaged. Since the gear 17 does not move in the axial direction relative to the gear 18 on the output side, there is no meshing at the meshing portion. Also, in this example,
Since the relationship is set such that the face angle α>the face angle β, unlike the conventional example, when the parts are separated, they do not understand each other and are not separated.

Effects of the invention In the present invention, the face angle of at least one of the two engaging teeth of the clutch member is set to 10 degrees or more, and the face angle of one engaging tooth is set to be greater than the face angle of the other engaging tooth. The large structure prevents the engaging teeth from biting into each other at the initial stage of clutch disengagement, and when receiving reverse torque from the load side,
Since a component force is generated in the direction of separating both clutch members from each other on these tooth surfaces, the elasticity of the coil spring for separating the clutch members may be small, or may be omitted if necessary. Therefore, when the clutch member is disengaged, the frictional contact pressure between the second gear and the casing is weakened, and the second gear on the output side and the reversal torque required to return the gear can be minimized.

In addition, since the clutch member on the driven side and the second gear are separate bodies and are combined in a state where only rotation can be transmitted, when the clutch member is pulled apart,
There is no sliding between the tooth surfaces.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a small electric motor with a clutch, Figure 2
Figures 3 and 3 are developed side views of the engaging teeth. 1... Small electric motor with clutch, 2... Casing, 3... Rotor, 7... First gear, 11, 12
...clutch member, 11a, 12a...engaging teeth,
12c...Engagement hole, 14...Coil spring,
17... Second gear, 17b... Engaging pawl, 18...
gear.

Claims (1)

[Claims for Utility Model Registration] (1) Rotation of the rotor is controlled by the engagement of a clutch member provided on a corner opposite surface of a first gear in a gear train and a second gear that rotates coaxially with the first gear. In a small electric motor with a clutch in which transmission is transmitted to an output gear by engagement and disengagement of teeth, at least one of the engaging teeth has a face angle α of 10 degrees or more, and a face angle β greater than the other face angle β. A small electric motor with a clutch, characterized in that it is configured so that. (2) The clutch member on the disengagement side and the second gear are assembled separately and slidably in the axial direction, and an engagement means for transmitting only rotation is provided between them. A small electric motor with a clutch according to claim 1 of the utility model registration claim.