JPH0329981Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a small synchronous motor with a reduction gear mechanism having a built-in clutch.

[Prior art]

Conventional geared motors transmit the rotation of the rotor to the output shaft through the meshing of only the reduction gear train, so when the rotor is started, the rotation speed curve r has a sharp rise as shown in the width w as shown in Figure 12. Therefore, due to the moment of inertia of the load, a transient peak occurs as indicated by p in the load curve f in Fig. 13, and then a steady rotation occurs as indicated by the rotational speed curve r in Fig. 12, and the load curve f in Fig. 13 occurs. Generally, the motor is in a steady load state, and a large power motor is required to reliably start up against the transient peak load of p, which increases the size and is disadvantageous in terms of cost. At the same time, transient peaks were not resolved, resulting in insufficient characteristics and quality defects.

In order to eliminate the above-mentioned drawbacks, a friction clutch is provided in which a plate 6 and an output gear 5 are fitted to the output shaft 4, and a spring washer 20 is fixed to the output shaft 4 by caulking, as shown in FIG. As shown in Fig. 5, the rotational speed curve R has a slow rise characteristic, and the load curve F has extremely low transient peaks as shown in Fig. 5, and the friction clutch is designed to prevent internal damage due to external force. The attached motor is in practical use.

However, the friction clutch has large variations, making it difficult to manage the friction torque.
If the slip surface repeatedly slips due to wear, the friction torque decreases, and the torque relationship can easily be set as friction torque > motor torque > load torque, but when friction torque≫motor torque, the friction torque decreases as shown in Fig. 12 above. As a result, the start-up at startup becomes abrupt, and a transient peak occurs as shown in FIG. 13.

On the other hand, if the torque relationship is motor torque>friction torque>load torque, under ideal conditions, the rise at startup is slow as shown in Figure 5 above, and the friction without transient peaks is as shown in Figure 6. Although a motor with friction torque can be obtained, if the torque relationship is disrupted, it may cause idling or the friction effect may be lost, resulting in poor starting performance. For this reason, a relationship of motor torque≫load torque was required, which had the disadvantage of having to use a large motor.

A similar effect can be obtained by elastically connecting the spring washer shown in Fig. 14 with a ratchet incorporating a metal spring or a coil spring, but when the spring material is made smaller, the stress increases and the material breaks due to fatigue. There are drawbacks such as.

[Purpose of invention]

In view of the above-mentioned drawbacks, the present invention provides that one of the rotating members in the transmission path from the rotor to the output shaft is composed of a driving side member and a driven side member, and that an actuator is activated between the driving side member and the driven side member. The first clutch, which absorbs the shock caused by external forces, and the second clutch, which is a non-transmission means, which prevents transmission when the torque exceeds the internal destruction limit due to external force, are made of the same polymeric elastic material, and the torque relationship between them is easy. The purpose of the present invention is to propose a small motor that can be set to the desired position, has satisfactory functions, and has a simple configuration with a small number of parts.

[Structure of the idea]

In the present invention, one of the rotating members in the transmission path from the rotor to the output shaft is composed of a driving side member and a driven side member, and between these driving side member and driven side member, there is a gap between the driving side member and the driven side member. The first clutch is formed by providing an elastic polymer body that absorbs the torque, and the second clutch is formed by providing a non-transmission means for preventing transmission when the torque exceeds an internal destruction limit caused by an external force on the elastic polymer body. be.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments. 1st
3 shows a first embodiment of the small synchronous motor. In FIG. The cup-shaped cases 2 are stacked one on top of the other, and a lid 11 is fixed to the upper opening of the cup-shaped cases 2.

A plurality of yokes 1a are cut upward at the bottom of the cup-shaped case 1, and a bobbin 10 is formed.
The lower end of a rotor shaft 12 is fixed to the center of the bottom, and the rotor 3 is rotatably fitted onto the rotor shaft 12.

A plurality of yokes 2a are cut and raised downward at the bottom of the cup-shaped case 2, and are arranged along the inner peripheral surface of the coil bobbin 10 so as to intertwine with the yokes 1a alternately. A large-diameter round hole 2b is bored, and the lower end of a fixed shaft 13 is fixed to the outside of the hole 2b, and a reduction gear 14 is rotatably fitted to the fixed shaft 13. A rotational direction regulating lever 15 is fitted onto the outer periphery of the formed hollow gear shaft and is friction-coupled to be rotatable integrally with the gear shaft by a biasing member (not shown).

Bearings 16 and 17 are fixed to the bottom of the cup-shaped case 2 and the lid 11, respectively, and the output shaft 4 is supported, and the output gear 5, which is a driving side member, is fitted to the output shaft 4, which is a driven side member, and output is output. Another reduction gear 18 is disposed in mesh with the gear 5 and the pinion of the reduction gear 14.

The rotor 3 is composed of a synthetic resin hollow shaft portion 3a and a magnetized magnet 19 fitted into the hollow shaft portion, and a pinion 3b is integrally formed on the upper side of the hollow shaft portion 3a. The reduction gear 14 is meshed with the pinion 3b of the rotor 3.

On the lower side of the output shaft 4, a first plate 6 with a D-cut outer circumference and a round hole in the center, an output gear 5, a second plate 7, and a spring washer 20 with a D hole are fitted in order. 20 is fixed to the output shaft 4 by caulking. As shown in FIGS. 2 and 3, the output gear 5 has a plurality of round holes 5a, into which a polymeric elastic body 8 such as rubber or soft plastic is fitted, and the central through-hole of the polymeric elastic body 8 is fitted with a plurality of round holes 5a. is the pin-shaped protrusion 6 of the first plate 6 and the second plate 7.
a and 7a are inserted to form a first clutch that absorbs the shock at startup, and when the clutch is forcibly rotated between the output gear 5 and the spring washer 20 by an external force and exceeds the internal destruction limit torque α, the clutch is transmitted. A second clutch is configured to prevent this, and the torque relationship of the clutch is determined by the friction torque caused by the second clutch≫
Motor torque>Torque due to first clutch>Load torque, that is, as shown in FIG.
It is composed of clutch torque γ>load torque δ.

The operation of the small synchronous motor is such that when the rotor 3 is rotated, the rotation direction regulating lever 15 is rotated to restrict the rotation of the rotor 3 when the rotor 3 is rotating in the reverse direction, and when the rotor 3 is rotating in the forward direction, the rotation is decelerated. The impact is transmitted to the output gear 5, which is a driving side member, via the gears 14 and 18, and the impact at the time of startup is absorbed by the polymeric elastic body 8 engaged with the protrusions 6a and 7a of the first clutch, and the output gear 5 The rotation of the polymer elastic body 8
The rotation of the second plate 7 is transmitted to the first plate 6 and the second plate 7 via the projections 6a and 7a, and the rotation of the second plate 7 is transmitted via the spring washer 20 to the output shaft 4, which is a driven member.

When a small synchronous motor is configured as described above, unlike a conventional clutch using only a spring washer, the shock at startup is absorbed by the polymer elastic body 8, so the internal failure limit torque can be increased, making it slightly This eliminates the need for pressure adjustment, etc., and the rotation of the output shaft 4 becomes the rotational speed curve R shown in FIG. 5 and the load curve F without transient peaks shown in FIG. 6.

When the load connected to the output shaft 4 is excessive or when the output shaft 4 is forcibly rotated by an external force, if the internal destruction limit torque α is exceeded, the second clutch will slip between the output shaft 4 and the output gear 5. When this occurs, rotation is not transmitted and problems such as chipped gear teeth do not occur. The friction clutch formed by the spring washer 20 may be constituted by a ratchet clutch or the like.

In FIG. 1, the rotation of the rotor is stopped by the rotation restriction lever 15 during reverse rotation, but the present invention may be applied to a motor that can rotate in forward and reverse directions or a motor that always rotates in the forward direction and does not have a rotation restriction lever.

Figure 7 and the following are other examples of shapes in which an elastic polymer body that absorbs the shock at startup is incorporated into the driving side member and the driven side member, and also prevents transmission when the internal destruction limit torque α is exceeded. A second clutch is constructed using the polymer elastic material.

Figures 7 and 8 show a second embodiment, in which a first plate 6 with a D hole in the center and a second plate are attached to a D-cut output shaft 4.
The plates 7 are fitted so as to sandwich the output gear 5 having a round hole, and the second plate 7 is caulked and fixed to the output shaft 4, and the output gear 5 is formed with a downward concave portion 5b and the bottom of the concave portion 5b. A plurality of pins 5c are protrudingly provided in the recessed portion 5b, and an elastic polymer body 9 having a through hole into which the pins 5c are fitted is fitted, and the pins 5c and the elastic polymer body 9 constitute a first clutch. Semicircular notches 9a are formed at intervals on the outer periphery of the elastic polymer body 9, and pin-shaped protrusions 7a of the second plate 7 are fitted into the notches 9a to form a second clutch.

The operation of the output shaft 4, which is a driven side member, and the output gear 5, which is a driving side member, is such that the rotation of the rotor is transferred from the output gear 5 to the polymer elastic body 9 via the pin 5c.
It is further transmitted to the output shaft 4 via the second plate 7 due to the engagement between the polymer elastic body 9 and the protrusion 7a. The impact generated by the starting rotation of the rotor is absorbed by the elastic polymer body 9 engaged with the pin 5c and the protrusion 7a, and is not transmitted to the output shaft 4. When the output shaft 4 is forcibly rotated by an external force and exceeds the internal destruction limit torque α, the second clutch rotates the protrusion 7.
a is moved from one of the notches 9a over the outer periphery to another notch 9a, resulting in a non-transmission state and the rotation of the output shaft 4 is not transmitted to the output gear 5, resulting in problems such as chipping of the tooth profile of the gear. Does not occur.

In the above description, the elastic polymer body 9 may be fixed to the second plate 7 with a protrusion, and the pin provided on the output gear 5 may be engaged with the semicircular arc notch 9a.

FIG. 9 shows a third embodiment, in which the pin 5c of the output gear 5
A through hole in the elastic polymer body 9 is fitted into the upper surface of the elastic polymer body 9, and the convex portion 6b of the first plate 6 is pressed against the upper surface of the elastic polymer body 9 to form a first clutch and a second clutch. .

The output gear 5 is rotated by the rotation of the rotor, and the impact generated by the starting rotation of the rotor is applied to the elastic polymer body 9 at the position where the protrusion 6b of the first clutch is pressed.
When the output shaft 4 is forcibly rotated by an external force and exceeds the internal destruction limit torque α, the convex portion 6b of the second clutch slides on the upper surface of the polymer elastic body 9 and is moved to transmit the rotation. is prevented.

In the above description, the protrusion may be provided on the output gear 5, or the protrusion may be provided on the output gear 5.
A convex portion may be provided on both the plate 6 and the output gear 5.

10 and 11 show a fourth embodiment, in which a round hole is bored in the center of the output gear 5, round holes or D holes are bored in the first plate 6 and the second plate 7, and the polymer elastic material The second plate 7 is fixed to the output shaft 4 by caulking, and the second plate 7 is fixed to the output shaft 4 by fitting into the output shaft 4 formed in the D cut. The pin 5c of the output gear 5 is fitted to constitute the first clutch, and the D hole 9 of the polymer elastic body 9 is inserted into the first clutch.
A through hole 9c is bored in the vicinity of point b, and the D cut of the output shaft 4, the D hole 9b of the polymer elastic body 9, and the through hole 9c constitute a second clutch.

When the rotor is rotated, the output gear 5 is rotated, and the impact generated by the rotor's starting rotation is absorbed by the polymer elastic body 9 that engages with the pin 5c of the first clutch, and the output shaft 4 is forcibly rotated by external force. When the rotation exceeds the internal destruction limit torque α, the D cut of the output shaft 4 of the second clutch elastically deforms the D hole 9b of the polymer elastic body 9, resulting in a non-transmission state and the rotation of the output shaft 4 becomes an output. It is not transmitted to gear 5. The through hole 9c of the polymer elastic body 9 may be omitted.

In the above description, the first
Although a clutch and a second clutch are provided, the rotor 3 and the output shaft 4 transmit the rotation of the rotor 3 to the output shaft 4.
It may also be provided on other reduction gears 14 or 18 between the two.

[Effect of idea]

As described above, in the present invention, one of the rotating members in the transmission path from the rotor to the output shaft is composed of a driving side member and a driven side member. The first clutch has an elastic polymer body that absorbs the impact when the rotor The absorption of the shock that occurs during startup rotation and the non-transmission state when the output shaft is forcibly rotated due to excessive load or external force and the internal destruction limit torque is generated are handled separately with a simple configuration. The torque relationship between the two clutches can be easily set, and each function is satisfied without deteriorating the durability performance of the second clutch.The non-transmission means allows the internal destruction limit torque to be set at a higher torque than the motor torque, making it easy to engage the clutch. There is no idling. Further, it is possible to provide a small motor that has a minimum number of components, is compact, does not require delicate pressure adjustment, and has excellent practical effects such as low cost.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIGS. 1 to 3 show the first embodiment, FIG. 1 is a cross-sectional side view of a small synchronous motor, FIG. 2 is a cross-sectional side view of the main part of an output gear, Fig. 3 is a bottom view of the output gear shown in Fig. 2, Fig. 4 is an explanatory diagram of the torque relationship, Fig. 5 is a rotational speed curve diagram,
Figure 6 is a load curve diagram, Figures 7 and 8 are the second embodiment, Figure 7 is a sectional side view of the output gear, Figure 8 is a sectional bottom view of the same essential parts, and Figure 9 is the third embodiment. In the examples, FIGS. 10 and 11 are cross-sectional side views of the output gear, and FIG. 10 is a cross-sectional side view of the output gear, and FIG.
Figure 1 is a sectional plan view of the same main part, Figure 12 is a rotation speed curve diagram with a sudden rise at startup of the conventional geared motor, Figure 13 is a load curve diagram with the same transient peak load, and Figure 14 is a diagram of the rotation speed curve with a sudden rise at startup. The figure is a cross-sectional side view of the main part of a conventional small synchronous motor with a friction clutch, with the case cut away. 3... Rotor, 4... Output shaft, 8, 9... Polymer elastic body, α... Internal destruction limit torque.

Claims (1)

[Scope of utility model registration request] In a small synchronous motor that has a rotor that is driven to rotate and an output shaft that is connected to the rotor through a reduction gear train, the output shaft rotates as the rotor rotates, from the rotor to the output shaft. One of the rotating members in the transmission path is composed of a driving side member and a driven side member, and an elastic polymer body is provided between the driving side member and the driven side member to absorb shock at the time of startup. A small synchronous motor, characterized in that the first clutch is constituted by a first clutch, and the second clutch is constituted by providing a non-transmission means for preventing transmission when an internal destruction limit torque due to an external force is exceeded in the polymer elastic body.