JP6541178B2 - POWER TRANSMISSION DEVICE AND ROTARY DRIVE DEVICE - Google Patents

Description

  The present invention relates to a power transmission device for preventing backlash in a gear transmission mechanism and a rotational drive device using the same.

For example, in a gear transmission mechanism for driving a reel that causes a plurality of pictures or characters displayed on the outer peripheral surface to be selectively displayed from a window (opening), a reel (target for rotational drive) is used without using reduction gears. Method) is desirable to directly connect a hybrid motor capable of obtaining stable rotation at low speed. However, in place of the expensive hybrid motor, although the cost is lower than that of the hybrid motor, a PM motor having a large rated rotational speed is used, and the output of this PM motor is decelerated by the gear reduction mechanism to rotate the reel etc. The cost of the device may be reduced.
However, as long as power is to be transmitted using gears, there is a backlash between the reduction gear and the motor gear, so when the reel is stopped, the motor is stopped together with the gear and the motor that is about to rotate by the inertia force of the reel. Vibration occurs with the gear and it is difficult to stop smoothly. Also, the tooth surface collides with and leaves the gear tooth surface in a gap corresponding to backlash, and the tooth surface collides, for example, a distracting noise. May occur.

  On the other hand, the presence of backlash is essential for the smooth rotation of the gear transmission mechanism, and if the backlash is simply reduced and eliminated, the torque loss may be lost or the torque may become excessive to obtain the same load of rotation transmission. In some cases, slight external forces or the presence of foreign matter may cause the gears to bite into one another and become inoperable. In addition, even if the gear transmission mechanism can rotate without causing the problems as described above, the motor vibration is transmitted to the reduction gear and the shaft, the reel, the sheet metal, etc., which is a part after that, causing a large resonance. Sound is more likely to occur.

Then, in order to solve such a problem, in the display device disclosed in Patent Document 1, an intermediate gear that always urges the intermediate gear attached to the base plate so that there is no play between the motor pinion and the output gear. The configuration is provided with a biasing mechanism.
The intermediate gear biasing mechanism includes a support plate on which the intermediate gear is rotatably mounted, and a base attached to the base plate such that the intermediate plate can move so that the intermediate gear does not cause play in the motor pinion and the output gear. It is comprised from the attachment means to a board, and the biasing spring which biases the said support plate.

JP 2007-219124 A

By the way, in the technique disclosed in the above-mentioned Patent Document 1, means for attaching the support plate on which the intermediate gear is rotatably mounted to the movable base plate so that the intermediate gear does not cause play in the motor pinion and the output gear And a plurality of components such as a biasing spring for biasing the support plate.
For this reason, in the technique shown by the said patent document 1, the whole structure becomes complicated and there exists a problem that the cost for installation will cost.

  The present invention has been made in view of the above-described circumstances, and is effective in suppressing noises such as resonance noise and backlash generated when stopping a gear while suppressing the cost for installation with a simple overall configuration. Power transmission device and rotary drive device that can be prevented.

  In order to solve the above-mentioned subject, this invention proposes the following means. That is, in the present invention, an elastic body is provided at the tooth base of one gear when pressed against the tooth tip of the other gear when meshing with the other gear, and the elastic body is the tooth bottom of the one gear. From the top to the top so as to be exposed.

  According to the present invention, it is possible to effectively prevent the generation of abnormal noise such as resonance noise and the backlash that occurs when the gear is stopped, while the overall configuration is simple and the installation cost is low.

It is a schematic block diagram of the power transmission device which concerns on this invention, Comprising: (A) is a general view of a gear, (B) is a perspective view which shows the positional relationship of a gear and an elastic body. It is a perspective view showing the reel unit to which the power transmission concerning the present invention is applied. It is a front view which shows the internal structure of the reel unit of FIG. It is a top view which shows the mesh | engagement location of a gear. (A) is a perspective view which shows the positional relationship of a gearwheel and an elastic body, (B) is sectional drawing which cut | disconnected (A) by the VV line.

  A power transmission 1 according to the present invention will be described with reference to FIGS. 1 (A) and 1 (B). FIG. 1A is a view showing the entire power transmission device 1, and FIG. 1B is a perspective view showing a positional relationship between a gear and an elastic body.

The power transmission device 1 is an elastic body 4 that is pressed and deformed by the tooth portions 2A and 3A of the gears 2 and 3 when the gears 2 and 3 mesh with one gear 2 and the other gear 3 that mesh with each other. It is characterized in that it is provided.
The elastic body 4 is disposed so that the upper part is exposed from the bottom 2B of one gear 2, and when one gear 2 meshes with the other gear 3, the inside of the tooth portion 2A of the gear 2 is Is pushed by the tooth tips of the tooth portion 3A of the gear 3 and deformed.
Further, the elastic body 4 has a rotation locus R1 larger than the rotation locus R2 at the tooth bottom 2B of the gear 2, whereby the tip of the other gear 3 meshes with the one gear 2 while deforming the elastic body 4. It will be.
As a result, in the power transmission device 1 described above, the elastic body 4 is interposed between the gears 2 and 3 to provide a cushioning effect, thereby causing the tooth surfaces of the gears 2 and 3 to repeatedly contact and separate. It is possible to prevent the generation of sound and to prevent the backlash that occurs when the gears 2 and 3 are stopped.

As described above in detail, according to the power transmission device 1 of the present invention, when meshing with one gear 2 with the other gear 3, the elastic body 4 is deformed by being pushed by the tip of the gear 3. Provided. The elastic body 4 is formed to have a rotation locus larger than the tooth bottom 2B of one gear 2 and therefore, when the one gear 2 and the other gear 3 mesh with each other, the other gear 3 is engaged. The tip of the gear is engaged with the one gear 2 while deforming the elastic body 4. Thus, in the power transmission device 1 according to the present invention, the elastic body 4 being interposed between the gears 2 and 3 provides a cushioning effect, and the tooth surfaces of the gears 2 and 3 are repeatedly contacted and separated. It is possible to prevent the generation of abnormal noise that occurs in the above and effectively prevent the backlash that occurs when the gears 2 and 3 are stopped.
Further, in the power transmission device 1 according to the present invention, the configuration is merely provided with the elastic body 4 between one gear 2 and the other gear 3, so that the overall configuration is simple and the cost for installation is reduced. Can.

(Embodiment)
One embodiment of the present invention will be described with reference to FIGS.
FIGS. 2 and 3 show a reel unit 10 as a rotational drive device to which the present invention is applied, and a stepping motor 12 installed on the unit main body 11 and a driving shaft 12A of the stepping motor 12 are pivotally supported. The drive gear 13, the reduction gear 14 driven by the drive gear 13, and the reel 15 integrally rotating with the reduction gear 14 are main components.
Among such components, the power transmission apparatus 100 according to the present invention is configured by the elastic body 16 installed in the reduction gear 14 together with the drive gear 13 and the reduction gear 14. The reduction gear 14 corresponds to one gear, and the drive gear 13 corresponds to the other gear.

As a stepping motor 12 serving as a driving source, a PM motor using a permanent magnet as a rotor is used, and a driving gear 13 is axially supported by a driving shaft 12A of the stepping motor 12.
A reduction gear 14 serving as a driven gear is engaged with the drive gear 13, and a reel 15 which is integrally rotated with the reduction gear 14 is fixed to a rotation shaft 17 of the reduction gear 14.
The reel 15 includes a hub 18 located at the center, a plurality of spokes 19 radially extending from the hub 18, and a ring-shaped reel body 20 disposed outside the spokes 19. The central hub 18 is attached to the end of the rotation shaft 17 of the reduction gear 14 via a bush 21 and a spring member 22. The rotation shaft 17 of the reduction gear 14 is installed in the unit body 11.

Further, a rotation amount detection sensor 30 is provided on the moving path of the spokes 19 on the reel 15.
The rotation amount detection sensor 30 includes a detection target piece 31 provided on one of the spokes 19 and a detection element 32 fixed to the unit main body 11 to detect passage of the detection target piece 31. The amount of rotation of the reel 15 is determined by counting the pulses output from the detection sensor 32 each time the detected piece 31 passes.

  Next, with reference to FIGS. 4 and 5A and 5B, the power transmission apparatus 100 according to the present embodiment, which includes the drive gear 13, the reduction gear 14 and the elastic body 16, will be described.

The power transmission device 100 is provided with an elastic body 16 which is pressed and deformed by the tooth portions 13A and 14A of the gears 13 and 14 when the gears 13 and 14 mesh with each other in the drive gear 13 and the reduction gear 14 meshing with each other. It has a feature in
Further, the tooth form of the gears 13 and 14 is an involute tooth form. Normal involute tooth profiles are often used with appropriate backlash, and the elastic body 16 according to the present invention is installed to suppress backlash, so that the gears 13 and 14 can be properly engaged. It is preferable that the tooth shape on the side of the gears 13 and 14 be set to a minus transition in which the tip is sharpened.
Further, as the elastic body 16, specifically, an O-ring made of rubber or the like having a circumferential length and a wire diameter which can be accommodated in the annular groove 40 along the circumferential direction in the reduction gear 14 is used. When meshing with the gear 13, the tooth tip of the tooth 13 A of the gear 13 is pushed in the tooth 14 A of the gear 14 to be elastically deformed.

  As shown in FIGS. 5A and 5B, the annular groove 40 in which the elastic body 16 is accommodated is formed deeper than the bottom 14B in the reduction gear 14, and the cross-sectional shape is formed in a semicircular shape. It is formed endlessly along the circumferential direction of the tooth portion 14A of the reduction gear 14.

  When the elastic member 16 is fitted in such an annular groove 40, the upper portion of the elastic member 16 is slightly exposed above the bottom 14B of the reduction gear 14 as shown in FIG. 5B. Positioned to Thereby, the elastic member 16 has its rotation locus R1 'larger than the rotation locus R2' at the tooth bottom 14B of the reduction gear 14, and when the reduction gear 14 meshes with the drive gear 13, the tooth portion 13A of the drive gear 13 It is pressed by the tooth tip and deformed.

As a result, when the stepping motor 12 is driven, there is no backlash because the tooth portion 13A of the drive gear 13 is always in contact with either the tooth portion 14A of the reduction gear 14 or the O ring which is the elastic member 16. The same state is achieved, and the generation of vertical vibration and rattling noise when the reel is stopped is prevented.
Although the annular groove 40 shown in FIGS. 5A and 5B is disposed at the center in the width direction of the tooth portion 14A of the reduction gear 14, its installation location is not limited to the center, and It may be a position near any of the side surfaces and is not particularly limited.

As described above in detail, according to the power transmission device 100 according to the present embodiment, when the drive gear 13 meshes with the reduction gear 14, the elastic body 16 that is pressed and deformed by the tooth tip of the drive gear 13 decelerates It is provided in the gear 14. Since this elastic body 16 is formed to have a rotation locus larger than the tooth bottom 14 B of the reduction gear 14, when the reduction gear 14 and the drive gear 13 mesh, the tooth tip of the drive gear 13 is It will mesh with the reduction gear 14 while deforming the elastic body 16.
Thus, in the power transmission apparatus 100 according to the present embodiment, the interposition of the elastic body 16 between the gears 13 and 14 exerts a cushioning effect, and the tooth surfaces of the gears 13 and 14 contact or separate. It is possible to prevent the generation of abnormal noise caused by repetition and effectively prevent the backlash that occurs when the gears 13 and 14 are stopped.
Further, in the power transmission device 100 according to the present embodiment, the configuration is merely provided with the elastic body 16 between the reduction gear 14 and the drive gear 13, so that the overall configuration is simple and the cost for installation can be reduced. it can.
Further, in the power transmission device 100 according to the present embodiment, by providing the elastic body 16 serving as the O-ring on the reduction gear 14 having a larger number of teeth than the drive gear 13, the tooth tips and teeth are provided compared to the case of providing on the drive gear 13 side. The chance of contact is reduced, and the elastic body 16 can be used for a long time.

(Modification)
In the above embodiment, the elastic body 16 which is an O-ring is provided on the reduction gear 14, but may be provided on the drive gear 13 side.

Further, in the above embodiment, the O-ring used as the elastic body 16 can be selected from various elastic materials in addition to the rubber material.
Further, the drive gear 13 and the reduction gear 14 may be formed of metal or may be formed of high-strength plastic, and the constituent materials thereof are not limited.

  Further, in the power transmission device 100 shown in the above-described embodiment, the elastic body 16 is interposed between the drive gear 13 and the reduction gear 14, but the same may be adopted for linear movement by rack and pinion. Specifically, a groove may be formed on the bottom of any of these racks and pinions, and the elastic body may be accommodated in the groove.

  Further, in the above embodiment, the stepping motor 12 is adopted as the drive source, but with this stepping motor, the resolution (step angle) is coarse, and the smaller the gear reduction ratio, the above-mentioned problem of resonance noise or backlash occurs. Cheap. Therefore, in place of such a stepping motor 12, another motor (a hybrid motor excellent in resolution, a servomotor capable of feedback in position, or the like) may be used.

Further, the annular groove 14 into which the O ring which is the elastic body 16 is fitted may be formed by processing a groove in the integral gear 14 or two gears of divided structure are united (corresponding to a groove at the center There may be a small diameter boss portion, and a structure in which gears are formed around both ends of the boss.
In addition, when it is a gear of a division | segmentation structure, a backlash can also be made small because a play comes out in the opposite direction by slightly shifting and setting the phase of two gearwheels in the circumferential direction. That is, in addition to fitting the elastic body 16 into the annular groove 14, resonance noise or backlash can be synergistically prevented by slightly shifting the phases of the two gear wheels in the circumferential direction.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like within the scope of the present invention are also included.

  The present invention relates to a power transmission device that can prevent abnormal noise such as resonance noise and backlash that occurs when a gear is stopped.

1 Power Transmission Device 2 One Gear 2A Tooth 2B Tooth Bottom 3 Other Gear 3A Tooth 4 Elastic Body 13 Drive Gear 14 Reduction Gear 14 A Tooth 14B Tooth Bottom 16 Elastic Body 40 Annular Groove

Claims (8)

Of the gears that mesh with each other, at the bottom of only one gear that rotates integrally with the reel, at least one of the characters or figures, is pressed by the other gear's tooth tip while meshing with the other gear. Provide an elastic body that
The elastic body is disposed so that the upper part is exposed from the bottom of the one gear ,
The power transmission apparatus according to claim 1, wherein the one gear has more teeth than the other gear .   The power transmission apparatus according to claim 1, wherein the elastic body has a rotation locus larger than a tooth base of the one gear.   The power transmission device according to any one of claims 1 and 2, wherein the elastic body is disposed in an annular groove formed along a circumferential direction in a tooth portion of the one gear.   The power transmission device according to claim 3, wherein the elastic body disposed in the annular groove is formed by an O-ring. Said annular groove, said formed deeper than the tooth gap on one of the gears, when fitted the elastic body, any one of claims 3 or 4, characterized in that the top comes out slightly from the tooth bottom of the gear The power transmission device according to item 1. The power transmission device according to any one of claims 3 to 5 , wherein the annular groove is formed at the center in the width direction of the tooth portion of the one gear . The power transmission apparatus according to any one of claims 1 to 6, wherein the other gear is a power gear, and the one gear is a reduction gear driven by the other gear. The power transmission device according to any one of claims 1 to 7 , wherein a tooth portion of the gear has a shape which is shifted to a negative direction more loosely than an involute tooth.

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