CN111106715A - Overload protection mechanism and gear motor with same - Google Patents
Overload protection mechanism and gear motor with same Download PDFInfo
- Publication number
- CN111106715A CN111106715A CN201910986560.1A CN201910986560A CN111106715A CN 111106715 A CN111106715 A CN 111106715A CN 201910986560 A CN201910986560 A CN 201910986560A CN 111106715 A CN111106715 A CN 111106715A
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- Prior art keywords
- annular plate
- overload protection
- protection mechanism
- rotating shaft
- shaft
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- 230000007246 mechanism Effects 0.000 title claims abstract description 41
- 230000009467 reduction Effects 0.000 claims abstract description 29
- 230000002093 peripheral effect Effects 0.000 claims abstract description 27
- 239000002184 metal Substances 0.000 claims abstract description 17
- 230000005540 biological transmission Effects 0.000 claims description 35
- 230000002265 prevention Effects 0.000 claims description 7
- 238000004381 surface treatment Methods 0.000 claims description 6
- 230000000630 rising effect Effects 0.000 claims description 2
- 239000011347 resin Substances 0.000 description 52
- 229920005989 resin Polymers 0.000 description 52
- 230000004048 modification Effects 0.000 description 7
- 238000012986 modification Methods 0.000 description 7
- 238000009413 insulation Methods 0.000 description 4
- 240000006829 Ficus sundaica Species 0.000 description 3
- 238000005121 nitriding Methods 0.000 description 3
- 229920001707 polybutylene terephthalate Polymers 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012777 electrically insulating material Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920006324 polyoxymethylene Polymers 0.000 description 2
- 229930182556 Polyacetal Natural products 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- -1 polybutylene terephthalate Polymers 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
- H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
- H02K7/102—Structural association with clutches, brakes, gears, pulleys or mechanical starters with friction brakes
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
- H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
The invention provides a speed reduction motor which restrains the deviation of threshold torque of an overload protection mechanism utilizing friction resistance and is provided with the overload protection mechanism. The overload protection mechanism includes a rotating shaft, a rotating member having a shaft hole, and a first annular plate and a second annular plate which are annular metal plates, wherein the first annular plate has higher rigidity than the second annular plate, and when one side of the rotating shaft in the axial direction is set to be upper and the other side is set to be lower, the first annular plate is sandwiched between the upper surface of the rotating member and a diameter-expanded portion of the rotating shaft, the second annular plate is sandwiched between the lower surface of the rotating member and a deformed portion formed by pressing and plastically deforming a part of the rotating shaft upward relative to the second annular plate, and the inner peripheral side of the second annular plate is pressed by the deformed portion and elastically deformed upward.
Description
Technical Field
The present invention relates to an overload protection mechanism, and more particularly, to an overload protection mechanism using frictional resistance.
Background
Conventionally, there is known an overload protection mechanism that transmits a driving force of a driving source to an output portion during a normal operation and interrupts transmission of the driving force when an excessive load is applied for some reason, thereby protecting a driving target and a power transmission mechanism. As such an overload protection mechanism, for example, a friction transmission device using frictional resistance as shown in patent document 1 below is known. Patent document 1 below discloses a reduction motor 100 including a friction transmission device 1.
The friction transmission device 1 shown in patent document 1 includes: a rotating shaft 2; a cylindrical rotating member 4 having a hole 40 through which the rotating shaft 2 is inserted; an annular member 3 which is an annular metal plate through which the rotating shaft 2 is inserted; and a plate-like urging member 5. The annular member 3 is sandwiched between the other surface 48 (more specifically, the one-side convex portion 47) of the cylindrical rotating member 4 and the large-diameter portion 21 provided on the rotating shaft 2, and the plate-like urging member 5 is sandwiched between the one surface 46 (more specifically, the other-side convex portion 49) of the cylindrical rotating member 4 and a deformed portion 23a formed by squashing and plastically deforming a part of the rotating shaft 2 toward the other side L2 with respect to the plate-like urging member 5. The peripheral portion of the axial hole in the one surface 46 of the cylindrical rotating member 4 is recessed from the one-side convex portion 47 in contact with the plate-like urging member 5, and the inner peripheral portion 56 of the plate-like urging member 5 is pressed by the deforming portion 23a and elastically deformed toward the other side L2.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2014-58993
Disclosure of Invention
Technical problem to be solved by the invention
In the friction transmission device 1, the plate-like urging member 5 is elastically deformed toward the other end side L2 by the deformed portion 23a after press-forming. The deformed plate-like urging member 5 urges the cylindrical rotating member 4 to press the annular member 3. Thereby, the cylindrical rotating member 4 rotates integrally with the rotating shaft 2 by the frictional resistance generated between the plate-like urging member 5 and the annular member 3. When an external force exceeding the frictional resistance is applied to the rotary shaft 2, the rotary shaft 2 slides (idles) with respect to the cylindrical rotary member 4, and the external force is released.
The annular member 3 of the friction transmission device 1 is in contact with the other-side convex portion 49 of the cylindrical rotating member 4 on the outer peripheral side of the surface 31 of one side L1 thereof, and is in contact with the large-diameter portion 21 on the inner peripheral side of the surface 32 of the other side L2 thereof. Therefore, if the force of the press-formed deformed portion 23a becomes excessive, the annular member 3 is pressed by the cylindrical rotating member 4 and deformed, and there is a risk that the threshold torque at which the rotary shaft 2 starts to slip is disturbed.
In view of the above-described problems, an object of the present invention is to provide a reduction motor that suppresses variation in threshold torque of an overload protection mechanism that utilizes frictional resistance, and that includes the overload protection mechanism.
Technical scheme for solving technical problem
In order to solve the above-described problems, an object of the present invention is to provide an overload protection mechanism including: a rotating shaft; a rotating member having a shaft hole through which the rotating shaft is inserted; and a first annular plate and a second annular plate which are annular metal plates through which the rotating shaft is inserted, wherein the first annular plate is more rigid than the second annular plate, and when one side of the rotating shaft in the axial direction is set to be up and the other side is set to be down, the first annular plate is sandwiched between an upper surface of the rotating member and a diameter-enlarged portion provided on the rotating shaft, the second annular plate is sandwiched between a lower surface of the rotating member and a deformed portion formed by flattening and plastically deforming a part of the rotating shaft upward with respect to the second annular plate, a peripheral portion of the shaft hole in the lower surface of the rotating member is recessed from a portion in contact with the second annular plate, and an inner peripheral side of the second annular plate is pressed by the deformed portion and elastically deformed upward.
By using a metal plate having higher rigidity than the second annular plate as the first annular plate, the first annular plate can be prevented from being deformed by a force applied when the deformation portion is formed. On the other hand, since the second annular plate is used as the disc spring in the present invention, the second annular plate needs to be deformed and assembled. The threshold torque at which the rotary shaft and the rotary member start to slip is determined by the urging force accompanying the elastic deformation of the second annular plate. In the present invention, by using separate metal plates having different rigidities as the annular plates, deformation of the first annular plate is prevented, and variation in threshold torque can be suppressed.
Preferably, the first annular plate is surface-treated to increase its rigidity. The rigidity is improved by subjecting the first annular plate to a surface treatment such as nitriding treatment, and deformation of the first annular plate can be prevented without increasing the thickness of the first annular plate, that is, without hindering the miniaturization of the overload protection mechanism.
Further, the rigidity of the first annular plate may be increased by making the first annular plate thicker than the second annular plate. If the size and design requirements of the overload protection mechanism allow this, the rigidity can also be increased by thickening the first annular plate without performing surface treatment or the like.
In the overload protection mechanism according to the present invention, it is preferable that the upper surface of the rotating member is a flat surface.
The first annular plate and the rotating member are not in point-line contact with each other, but the entire surface of the rotating member side of the first annular plate is supported by the flat surface of the rotating member, whereby the first annular plate can be more reliably prevented from being deformed.
In the overload protection mechanism according to the present invention, it is preferable that the rotary shaft is made of metal, and a power transmission member made of resin is attached to a connection portion which is a portion of the rotary shaft above the first annular plate.
By using a resin power transmission member as a connecting portion with another device or another member, the overload protection mechanism of the present invention can be used also in an application requiring insulation between devices, for example.
In this case, it is preferable that a rotation stopper having a non-perfect circular shape in a plan view is formed in the connecting portion of the rotary shaft, and the power transmission member has a recess having the same shape as the rotation stopper and fitted in the rotation stopper. Preferably, the connecting portion of the rotating shaft is press-fitted into a recess provided in the power transmission member. The device is used for preventing the reduction of the action precision caused by the looseness and the clearance of the power transmission component.
In order to solve the above-described problems, an object of the present invention is to provide a reduction motor including: a rotor and a stator; the overload protection mechanism of the present invention; and a cover plate which is a plate-like member constituting a part of a housing for holding the rotor, the stator, and the overload protection mechanism, wherein the cover plate is formed with an opening for exposing the power transmission member of the overload protection mechanism to the outside of the housing, and the power transmission member has a disengagement prevention portion having a diameter larger than a diameter of the opening.
The power transmission member has a slip-off prevention portion having a diameter larger than that of the opening portion of the cover plate, so that the power transmission member can be prevented from accidentally slipping off when the reduction motor is assembled or operated.
Preferably, the opening of the cover plate has a flange portion rising upward from an opening edge thereof, and an outer surface of the power transmission member faces an inner peripheral surface of the flange portion.
Since the outer surface of the power transmission member faces the flange portion of the cover plate, even when an external force is applied to the power transmission member, the flange portion prevents the power transmission member from falling down, thereby preventing the shaft of the power transmission member from falling down.
(effect of the invention)
As described above, according to the overload protection mechanism and the reduction motor including the overload protection mechanism of the present invention, it is possible to suppress variation in threshold torque at which the rotating shaft and the rotating member start to idle.
Drawings
Fig. 1 is a plan view and a side view of a shaft member according to an embodiment.
Fig. 2 is an exploded perspective view of the shaft member.
FIG. 3 is a side cross-sectional view of the shaft member.
Fig. 4 is a perspective view of the resin cap as viewed from the lower surface side of the resin cap.
Fig. 5 is a side cross-sectional view showing a modification of the shaft member.
Fig. 6 is a side cross-sectional view showing a modification of the shaft member.
Fig. 7 is a perspective view showing an external appearance of the reduction motor according to the embodiment.
Fig. 8 is a side sectional view showing an internal structure of the reduction motor.
Fig. 9 is a top perspective view showing a reduction gear mechanism of the reduction motor.
Description of the reference numerals
1: a reduction motor; 11: a motor housing; 12: a cover plate; 12 b: a burring (opening); 20: a stator; 30: a rotor; s: shaft members (overload protection mechanisms); 50: a shaft core portion (rotating shaft); 50 a: a connecting portion; 51: a front end portion; 51 a: an engaging portion (rotation stopper portion); 52: an expanding portion; 53: a spindle portion; 53 a: a fastening part; 54: a deformation section; 55: a base end portion; 60: gear parts (rotating parts, gear parts); 60 a: an upper surface; 60 b: a lower surface; 61: a middle section; 62: a middle section; 63: a shaft hole; 64: a tooth portion; 71. 71 t: an upper side washer (first annular plate); 71 a: a fastening part; 72: a lower washer (second annular plate); 72 a: a fastening part; 80: a resin cap (power transmission member); 81: a connecting portion; 81 a: a fastening part; 82: a large diameter portion; 821: a flange portion (slip-off prevention portion); 83: press-fitting a concave portion (recess); 83 a: a fastening part; 84: fitting recess
Detailed Description
[ summary of the constitution ]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The shaft member S described below is an overload protection mechanism in which two power transmission members rotate integrally by frictional resistance. The shaft member S has the following torque limiting function: the driving force of the driving source is transmitted to the output part during normal operation, and when an excessive load is applied to the output part for some reason, the transmission of the driving force is cut off, and the driving target and the power transmission mechanism are protected.
Fig. 1 is a plan view (a) and a side view (b) of the shaft member S. Fig. 2 is an exploded perspective view of the shaft member S. Fig. 3 is a side sectional view of the shaft member S. In the following description, "upper" and "lower" refer to directions parallel to the axis L shown in fig. 1 to 3, and an upper end side of the shaft member S shown in fig. 1 (b) is referred to as "upper" and a lower end side is referred to as "lower". In the shaft member S, the "tip end" is synonymous with the "upper end", and the "base end" is synonymous with the "lower end".
The shaft member S of the present embodiment includes a shaft core 50 as a rotation shaft, a gear member 60 as a gear member, an upper washer 71 (first annular plate) and a lower washer 72 (second annular plate) disposed so as to sandwich the upper and lower surfaces of the gear member 60, and a resin cap 80 as a resin shaft body. The gear portion 60 and the resin cap 80 are power transmission members that are connected to other devices and members, respectively, and transmit power, and are attached to the shaft core portion 50.
[ shaft core part ]
The shaft core portion 50 is a metal rotary shaft having a substantially cylindrical shape. The shaft core portion 50 has a radially enlarged portion 52 having a locally large diameter formed substantially at the center in the direction of the axis L. The base end portion 55 of the shaft core portion 50 and its vicinity are formed in a stepwise tapered manner.
The distal end portion 51 and the enlarged diameter portion 52 of the shaft core portion 50 constitute a connecting portion 50a to which the resin cap 80 is attached. The distal end portion 51 has a pair of engagement portions 51a whose circumferential surfaces are cut flat at circumferentially symmetrical positions. The engaging portion 51a is a rotation stopper for preventing the resin cap 80 from idling. A shank portion 53 to which the gear portion 60 is attached is provided between the enlarged diameter portion 52 and the base end portion 55 of the shaft core portion 50. The axle portion 53 has a pair of engagement portions 53a whose circumferential surfaces are cut flat at circumferentially symmetrical positions, as in the case of the distal end portion 51.
[ Gear parts ]
The gear portion 60 is a resin rotary member having a shaft hole 63 through which the axle portion 53 of the axle core portion 50 is inserted. A tooth 64 constituting a spur gear is formed on the outer peripheral surface of the gear portion 60. The upper surface 60a and the lower surface 60b of the gear portion 60 are formed such that the surface positions thereof are stepped down from the radially outer side to the radially inner side of the gear portion 60. On the upper surface 60a, a flat surface portion 61a is provided on the upper surface of the middle step portion 61 adjacent to the tooth portion 64. Similarly, on the lower surface 60b, a flat surface portion 62a is provided on the lower surface of the middle step portion 62 adjacent to the tooth portion 64.
[ gasket ]
The gear portion 60 of the shaft member S has upper and lower washers 71 and 72 disposed on upper and lower surfaces 60a and 60b thereof. The upper washer 71 is disposed between the enlarged diameter portion 52 of the shaft core portion 50 and the upper surface 60a of the gear portion 60. The lower washer 72 is disposed between the lower surface 60b of the gear portion 60 and a deformation portion 54 to be described later. The upper washer 71 and the lower washer 72 are members connecting the shaft core 50 and the gear portion 60 by frictional force.
The upper washer 71 is an annular metal plate through which the spindle portion 53 of the spindle portion 50 is inserted. The upper gasket 71 and the lower gasket 72 of the present embodiment have the same thickness. The upper gasket 71 is subjected to salt bath soft nitriding treatment to improve its rigidity. A pair of engagement portions 71a formed linearly are provided in the hole of the upper gasket 71 at circumferentially symmetrical positions. The engagement portion 71a of the upper washer 71 engages with the engagement portion 53a of the axle portion 53, and the upper washer 71 rotates integrally with the axle core portion 50. The outer peripheral edge of the lower surface of the upper gasket 71 is in contact with the flat surface portion 61a of the middle step portion 61. The upper surface of the upper washer 71 has an inner peripheral edge in contact with the enlarged diameter portion 52 and an outer peripheral edge in contact with the lower surface of the resin cap 80.
The lower washer 72 is an annular metal plate having a hole through which the spindle portion 53 of the spindle core portion 50 is inserted. As described above, the lower washer 72 and the upper washer 71 are the same in thickness. The lower gasket 72 is not subjected to surface treatment such as salt bath tufftride treatment. A pair of engaging portions 72a formed linearly are provided in the hole of the lower washer 72 at circumferentially symmetrical positions. The engagement portion 72a of the lower washer 72 engages with the engagement portion 53a of the axle portion 53, whereby the lower washer 72 and the axle core portion 50 rotate integrally. The outer peripheral edge of the upper surface of the lower washer 72 is in contact with the flat surface portion 62a of the middle step portion 62. As shown in fig. 3 (a) and (b), the inner peripheral edge of the lower surface of the lower gasket 72 is in contact with the deformed portion 54, and the deformed portion 54 is formed by pressing a part of the shaft core portion 50 to be crushed upward relative to the lower gasket 72 and plastically deformed.
[ resin Cap ]
The resin cap 80 is a resin shaft body having a substantially cylindrical shape. More specifically, the resin cap 80 is made of an electrically insulating resin material such as a POM (polyacetal) resin, a PBT (polybutylene terephthalate) resin, or a glass fiber-filled PBT resin. The material of the resin cap 80 is not limited to this, and other electrically insulating materials may be used. The resin cap 80 is composed of a connecting portion 81, a large diameter portion 82, and a flange portion 821 in this order from top to bottom, and these portions are continued to each other so as to be expanded in a stepwise manner from top to bottom.
The connection portion 81 is an output shaft or an input shaft connected to other devices or members. The connecting portion 81 has a pair of engaging portions 81a whose outer peripheral surfaces are cut flat at circumferentially symmetrical positions. The shape of the connecting portion 81 of the present embodiment, and the shape of the resin cap 80 of the present embodiment are merely examples, and may be appropriately changed according to the shape of other devices or members connected thereto.
Fig. 4 is a perspective view of the resin cap 80 as viewed from the lower surface side. As shown in fig. 3 and 4, the resin cap 80 has a hollow inside. A fitting recess 84 is formed in the lower surface of the resin cap 80, and the fitting recess 84 is an opening into which the enlarged diameter portion 52 of the axial core portion 50 is fitted. A press-fitting recess 83 is formed in the bottom surface of the fitting recess 84, and the press-fitting recess 83 is a recess into which the distal end portion 51 of the axial core portion 50 is press-fitted. The press-fitting recess 83 has the same shape as the distal end portion 51 of the shaft core portion 50, and has an engagement portion 83a on the inner peripheral surface thereof, the engagement portion 83a being a flat surface portion corresponding to the engagement portion 51a of the distal end portion 51. The engagement portion 83a of the press-fit recess 83 engages with the engagement portion 51a of the distal end portion 51, whereby the shaft core portion 50 and the resin cap 80 rotate integrally in the circumferential direction. In the present embodiment, the tip end portion 51 is press-fitted into the press-fitting recess 83 having the same shape as the tip end portion 51, so that a reduction in operation accuracy due to looseness or clearance of the resin cap 80 can be prevented. The shapes of the engaging portions 51a and 83a are not limited to those of the present embodiment, and the same anti-backlash effect as in the present embodiment can be obtained as long as the distal end portion 51 of the shaft core portion 50 is not perfectly circular in a plan view and the press-fitting recess 83 has a shape corresponding thereto.
In the shaft member S of the present embodiment, the power transmission members (the resin cap 80 and the gear portion 60) connected to other devices and members are formed of an electrically insulating material made of resin, and thus the shaft member S can be used for applications requiring insulation between devices, for example.
[ Friction Structure ]
Hereinafter, a friction structure in which the gear portion 60 and the resin cap 80 constituting the shaft member S are integrally rotated by frictional resistance will be described with reference to fig. 3.
The upper and lower surfaces 60a, 60b of the gear portion 60 of the shaft member S are sandwiched between the upper washer 71 and the lower washer 72. The upper washer 71 is sandwiched between the upper surface 60a of the gear portion 60 and the enlarged diameter portion 52 of the shaft core portion 50. The lower washer 72 is sandwiched between the lower surface 60b of the gear portion 60 and the deformation portion 54. The overload protection mechanism shown in the present embodiment is mainly configured by an upper washer 71 (first annular plate) and a lower washer 72 (second annular plate) disposed so as to sandwich the upper and lower surfaces of the gear portion 60 provided on the shaft member S shown in fig. 1.
The deformable portion 54 is pressed upward from the state of fig. 3 (b) by press working against the lower gasket 72. At this time, since the peripheral portion of the shaft hole 63 in the lower surface 60b of the gear portion 60 is recessed from the middle step portion 62 in contact with the lower washer 72, the inner peripheral edge of the lower washer 72 is pushed upward by the deforming portion 54 and elastically deformed so that the inner peripheral edge is raised upward. Thereby, the lower washer 72 functions as a disc spring and biases the gear portion 60 upward. Then, the biased gear portion 60 presses the upper gasket 71. Since the upper washer 71 is more rigid than the lower washer 72, it is not deformed even by the urging force of the lower washer 72. Thereby, the gear portion 60 rotates integrally with the axial core portion 50 by frictional resistance generated between the upper washer 71 and the lower washer 72. When an external force exceeding the frictional resistance is applied to the shaft member S, the upper and lower washers 71 and 72 and the gear portion 60 slide, the shaft core portion 50 or the gear portion 60 idles, and the external force is released.
Here, in the shaft member S of the present embodiment, a metal plate having higher rigidity than the lower washer 72 is used as the upper washer 71. This prevents the upper gasket 71 from being deformed by a force applied when the deformable portion 54 is press-formed.
The upper gasket 71 and the lower gasket 72 of the present embodiment have the same thickness. The upper gasket 71 is subjected to salt bath soft nitriding treatment, whereby the rigidity thereof is improved. The rigidity of the upper washer 71 is improved by performing surface treatment on the upper washer 71, and deformation of the upper washer 71 can be prevented without increasing the thickness of the upper washer 71, that is, without hindering the miniaturization of the shaft member S.
Further, since the lower washer 72 is used as a disc spring in the shaft member S, the lower washer 72 needs to be deformed and assembled. In the shaft member S of the present embodiment, by using a washer having higher rigidity than the lower washer 72 as the upper washer 71, the deformation of the upper washer 71 can be reliably prevented, and by this means, the lower washer 72 can be elastically deformed to a greater extent to increase the threshold torque. The "threshold torque" referred to herein is a torque at which one of the shaft core portion 50 and the gear portion 60 is fixed and the other starts to idle when an external force is applied to the other.
In this way, according to the shaft member S of the present embodiment, the deformation of the upper washer 71 is prevented, thereby suppressing the variation in threshold torque at which the hub portion 50 and the gear portion 60 start to idle. In addition, it is easy to set the threshold torque large.
[ modification of shaft Member ]
Fig. 5 and 6 are side sectional views showing modifications of the shaft member S. Fig. 5 and 6 are views showing another structure for preventing deformation of the upper gasket 71 according to the above embodiment. In the following description, the same or similar components as those of the above-described embodiment are denoted by the same reference numerals as those of the above-described embodiment, and detailed description thereof will be omitted.
In the above embodiment, the rigidity is improved by performing surface treatment on the upper gasket 71. In the modification of fig. 5, an upper washer 71t is used as a member corresponding to the upper washer 71 of the above-described embodiment, and the upper washer 71t is a metal plate thicker than the lower washer 72. The rigidity of the upper washer 71 can be improved by this structure if the dimensional requirements and design requirements of the shaft member S permit.
In the modification of fig. 6, the gear portion upper surface 60a of the above embodiment is not recessed in a stepped shape, but the entire upper surface 60a is designed to be a flat surface. The entire lower surface of the upper washer 71 is supported by the flat surface (upper surface 60a) of the gear portion 60, rather than the upper washer 71 and the gear portion 60 coming into point-line contact with each other, whereby the upper washer 71 can be more reliably prevented from being deformed.
[ reducing Motor ]
Fig. 7 is a perspective view showing an external appearance of the reduction motor 1 to which the shaft member S of the above embodiment is attached. In the following description, "upper" and "lower" refer to directions parallel to the z-axis indicated by coordinate axes drawn in fig. 7, and the z1 side is referred to as "upper" and the z2 side is referred to as "lower". The "front" and "rear" are directions parallel to the x axis indicated by the coordinate axes, and the x1 side is referred to as "front" and the x2 side is referred to as "rear". Similarly, "left and right" refers to a direction parallel to the y axis indicated by the coordinate axes.
The reduction motor 1 includes a bottomed cylindrical motor housing 11, a cover plate 12 as a plate-like member covering an opening at an upper end of the motor housing 11, and a terminal cover 15 attached to a front side of the motor housing 11.
The cover plate 12 is provided with an opening for exposing the resin cap 80 of the shaft member S to the outside of the housing, and a flange portion 12b which is a flange portion standing upward and is circular in a plan view is formed at an edge of the opening. The outer peripheral surface of the large diameter portion 82 of the resin cap 80 faces the inner peripheral surface of the burring portion 12 b. The cover plate 12 is provided with a pair of attachment pieces 12a extending in a tongue shape toward the left and right. The attachment piece 12a is a connection portion when the reduction motor 1 is assembled with an upper device thereof or the like.
The terminal cover 15 is attached to cover an opening provided in a part of the peripheral surface of the motor housing 11. The terminal cover 15 is composed of a base portion 151 attached to an opening of the motor housing 11 and a connector housing 152 provided to protrude forward from the base portion 151. Terminals 29 are held inside the connector housing 152 in a row on the left and right.
Fig. 8 is a side sectional view showing an internal structure of the reduction motor 1 when viewed from the direction a of fig. 7. The terminal 29 as a power supply terminal of the reduction motor 1 is a pin terminal having both ends bent upward and downward in the longitudinal direction. The downward bent portions of the terminals 29 are disposed in the connector housing 152, and constitute external connection portions 292 to which the terminals of the male connector are connected. The upwardly bent portions of the terminals 29 constitute binding portions 291 that bind coil wires of the stator coils 22, 27 (to be described later) of the reduction motor 1.
The reduction motor 1 of the present embodiment is a two-phase stepping motor, and the stator 20 thereof has an a-phase stator coil 22 wound on an a-phase bobbin 21 and a B-phase stator coil 27 wound on a B-phase bobbin 26. A terminal holding portion 21a, which is a thick portion for holding the terminal 29, is formed at the front edge of the phase a bobbin 21. The a-phase stator coil 22 has an upper yoke 23a and a lower yoke 23b as claw-pole salient poles. The B-phase stator coil 27 also has an upper yoke 28a and a lower yoke 28B. Further, a lower yoke 28B of the B-phase stator coil 27 is formed by a portion of the bottom surface of the motor housing 11 being cut into the motor housing 11.
The rotor 30 is disposed in the ring of the stator coils 22 and 27 with a predetermined air gap therebetween. The rotor 30 is composed of a rotor magnet 32 as a permanent magnet and a rotor holder 31 as a resin shaft body insert-molded in the rotor magnet 32. A shaft hole penetrating vertically is formed at the radial center of the rotor holder 31, and a rotor support shaft 39 as a fixed shaft is inserted into the shaft hole. The rotor support shaft 39 is fixed to the bottom surface of the motor housing 11 and the cover plate 12. The lower surface of the rotor 30 is supported by a plate spring 35, which is a leaf spring, and the rotor 30 is biased upward by the plate spring 35.
A gear plate 13 as a flat plate member is disposed on the upper surface of the stator 20. A pinion gear 31a as a gear portion is formed at an upper end of the rotor holder 31, and the pinion gear 31a protrudes upward from a through hole provided in the gear plate 13. A plurality of support shafts 49 are fixed to the upper surface of the gear plate 13 and the lower surface of the cover plate 12, and a first gear 41, a second gear 42, and a third gear 43, which will be described later, are rotatably supported on the support shafts 49. Further, a base end portion 55 of the shaft core portion 50 of the shaft member S is rotatably supported by a bearing 44c provided on the upper surface of the gear plate 13.
Fig. 9 is a top perspective view showing a reduction gear mechanism of the reduction motor 1. The first gear 41, the second gear 42, and the third gear 43 constituting the reduction gear mechanism are each a compound gear formed by integrally forming spur gears having different pitch circle diameters in the axial direction. The rotation of the pinion 31a is reduced in speed and transmitted to the shaft member S via the first gear 41, the second gear 42, and the third gear 43. Specifically, the pinion 31a meshes with the large diameter gear portion 41a of the first gear 41, and the small diameter gear portion 41b of the first gear 41 meshes with the large diameter gear portion 42a of the second gear 42. Similarly, the small-diameter gear portion 42b of the second gear 42 meshes with the large-diameter gear portion 43a of the third gear 43. The small-diameter gear portion 43b of the third gear 43 meshes with the gear portion 60 of the shaft member S.
The reduction motor 1 includes the overload protection mechanism described above, and transmits the rotational power output from the motor unit including the rotor 20 and the stator 30 to the gear unit 60 of the shaft member S, while interrupting the torque transmission when an overload occurs, and allowing the relative rotation between the motor unit and the gear unit 60. That is, when the torque between the motor portion and the gear portion 60 is less than or equal to the frictional force generated between the upper and lower washers 71 and 72 and the middle step portions 61 and 62 of the gear portion 60, the motor portion and the gear portion 60 rotate integrally, and therefore, the driving force of the motor portion is transmitted to the gear portion 60 via the upper and lower washers 71 and 72. When the torque between the motor portion and the gear portion 60 exceeds the frictional force acting between the upper and lower washers 71, 72 and the middle step portions 61, 62, the upper and lower washers 71, 72 slide relative to the middle step portions 61, 62, and therefore, the transmission of the torque from the motor portion to the gear portion 60 is cut off. Thereby, the relative rotation of the gear portion 60 and the motor portion can be permitted. Therefore, even when an excessive load is applied to the gear portion 60 side, damage to the gear can be prevented.
[ shaft Member holding Structure ]
The structure of the reduction motor 1 holding the shaft member S will be described below with reference to fig. 8.
The base end portion 55 of the shaft core portion 50 of the shaft member S is rotatably supported by a bearing 44c provided on the upper surface of the gear plate 13. As shown in fig. 8, the flange 821 of the resin cap 80 has a diameter larger than the diameter of the flange 12b of the cover plate 12. That is, the flange portion 821 functions as a slip-off prevention portion of the resin cap 80. Thereby, the resin cap 80 is prevented from being accidentally dropped off when the reduction motor 1 is assembled and operated.
The reduction motor 1 of the present embodiment uses the resin cap 80 made of resin as its output shaft, and can be used for applications requiring insulation between devices, for example. Further, since resin is more workable than metal, the resin cap 80 can be easily connected to various other devices by appropriately changing its shape. On the other hand, there are the following technical problems: the resin cap 80 is more likely to come off than the axial core portion 50 that exerts the slip-off prevention function using the gear portion 60. Accordingly, the flange 821 having a diameter larger than the diameter of the flange portion 12b is provided at the lower end of the resin cap 80, and the falling-off prevention function is exerted, whereby the advantage of the resin cap 80 can be utilized flexibly and the falling-off can be prevented.
In the reduction motor 1 of the present embodiment, the outer peripheral surface of the large diameter portion 82 of the resin cap 80 faces the inner peripheral surface of the flanged portion 12b of the cover plate 12 with a predetermined clearance. Thus, even when an external force is applied to the resin cap 80 in the radial direction, the burring 12b prevents the resin cap 80 from falling down, and prevents the shaft of the resin cap 80 from falling down. Further, since the cover plate 12 of the present embodiment is made of metal and the resin cap 80 is made of resin, they have advantages of good sliding property and no occurrence of dissimilar metal contact corrosion.
While the embodiments of the present invention have been described in detail, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention. For example, although the resin cap 80 and the shaft core 50 are formed as separate members in the above embodiment, in an application where insulation from other devices and members is not required, the portions corresponding to the resin cap 80 may be formed of metal and may be formed as a single component with the shaft core 50.
Claims (9)
1. An overload protection mechanism is characterized by comprising:
a rotating shaft;
a rotating member having a shaft hole through which the rotating shaft is inserted;
a first annular plate and a second annular plate which are annular metal plates through which the rotating shaft is inserted,
the first annular plate is more rigid than the second annular plate,
when one side of the rotating shaft in the axial direction is set to be up and the other side is set to be down,
the first annular plate is sandwiched between an upper surface of the rotating member and a diameter-enlarged portion provided on the rotating shaft,
the second annular plate is sandwiched between a lower surface of the rotating member and a deformation portion formed by plastically deforming a portion of the rotating shaft while pressing the portion upward with respect to the second annular plate,
a peripheral portion of the shaft hole in the lower surface of the rotating member is recessed from a portion in contact with the second annular plate,
the inner peripheral side of the second annular plate is pressed by the deformation portion and elastically deformed upward.
2. The overload protection mechanism of claim 1,
the first annular plate is subjected to surface treatment to increase the rigidity of the first annular plate.
3. The overload protection mechanism of claim 1,
the first annular plate is thicker than the second annular plate.
4. The overload protection mechanism according to any one of claims 1 to 3,
the upper surface of the rotating member is a flat surface.
5. The overload protection mechanism according to any one of claims 1 to 4,
the rotating shaft is made of metal and is provided with a rotating shaft,
a resin-made power transmission member is attached to a connecting portion that is a portion of the rotating shaft that is located above the first annular plate.
6. The overload protection mechanism of claim 5,
a rotation stopper having a non-perfect circular shape in a plan view is formed on the connecting portion of the rotating shaft,
the power transmission member has a recess having the same shape as the rotation stopper and fitted into the rotation stopper.
7. The overload protection mechanism of claim 5 or 6,
the connecting portion of the rotating shaft is press-fitted into a recess provided in the power transmission member.
8. A reduction motor is characterized by comprising:
a rotor and a stator;
the overload protection mechanism of any one of claims 5 to 7; and
a cover plate which is a plate-like member constituting a part of a housing that holds the rotor, the stator, and the overload protection mechanism,
an opening portion for exposing the power transmission member of the overload protection mechanism to the outside of the housing is formed in the cover plate,
the power transmission member has a slip-off prevention portion having a diameter larger than a diameter of the opening portion.
9. The geared motor according to claim 8,
the opening of the cover plate has a flange portion rising upward from an opening edge of the opening,
an outer surface of the power transmission member faces an inner peripheral surface of the flange portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-201848 | 2018-10-26 | ||
| JP2018201848A JP2020067168A (en) | 2018-10-26 | 2018-10-26 | Overload protection mechanism and geared motor equipped with the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111106715A true CN111106715A (en) | 2020-05-05 |
Family
ID=70389988
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921748351.5U Expired - Fee Related CN210927366U (en) | 2018-10-26 | 2019-10-17 | Overload protection mechanism and gear motor with same |
| CN201910986560.1A Withdrawn CN111106715A (en) | 2018-10-26 | 2019-10-17 | Overload protection mechanism and gear motor with same |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921748351.5U Expired - Fee Related CN210927366U (en) | 2018-10-26 | 2019-10-17 | Overload protection mechanism and gear motor with same |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2020067168A (en) |
| CN (2) | CN210927366U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112910164A (en) * | 2021-01-22 | 2021-06-04 | 珠海格力电器股份有限公司 | Rotor shaft and motor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020067168A (en) * | 2018-10-26 | 2020-04-30 | 日本電産サンキョー株式会社 | Overload protection mechanism and geared motor equipped with the same |
| CN113531004A (en) * | 2021-07-30 | 2021-10-22 | 脉冲电子（东莞）有限公司 | Overload protection mechanism and speed reducing motor with same |
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|---|---|---|---|---|
| JPH1014170A (en) * | 1996-06-19 | 1998-01-16 | Sankyo Seiki Mfg Co Ltd | Friction mechanism and compact motor with friction mechanism |
| JPH10201171A (en) * | 1997-01-10 | 1998-07-31 | Higashifuji Manuf Ltd | Motor fitted with clutch |
| CN101685997A (en) * | 2008-09-24 | 2010-03-31 | 日本电产三协株式会社 | Friction mechanism, gear motor, and method for manufacturing the friction mechanism |
| CN103671781A (en) * | 2012-09-14 | 2014-03-26 | 日本电产三协株式会社 | Friction transmission device and deceleration motor |
| CN104421349A (en) * | 2013-08-20 | 2015-03-18 | 日本电产三协株式会社 | Friction mechanism and gear motor |
| CN206694647U (en) * | 2017-03-30 | 2017-12-01 | 深圳市兰洋科技有限公司 | Angle valve handwheel closing device and its overload protecting mechanism |
| CN108027163A (en) * | 2015-09-29 | 2018-05-11 | 日本电产三协株式会社 | Air guiding plate device |
| CN210927366U (en) * | 2018-10-26 | 2020-07-03 | 日本电产三协株式会社 | Overload protection mechanism and gear motor with same |
-
2018
- 2018-10-26 JP JP2018201848A patent/JP2020067168A/en not_active Withdrawn
-
2019
- 2019-10-17 CN CN201921748351.5U patent/CN210927366U/en not_active Expired - Fee Related
- 2019-10-17 CN CN201910986560.1A patent/CN111106715A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1014170A (en) * | 1996-06-19 | 1998-01-16 | Sankyo Seiki Mfg Co Ltd | Friction mechanism and compact motor with friction mechanism |
| JPH10201171A (en) * | 1997-01-10 | 1998-07-31 | Higashifuji Manuf Ltd | Motor fitted with clutch |
| CN101685997A (en) * | 2008-09-24 | 2010-03-31 | 日本电产三协株式会社 | Friction mechanism, gear motor, and method for manufacturing the friction mechanism |
| CN103671781A (en) * | 2012-09-14 | 2014-03-26 | 日本电产三协株式会社 | Friction transmission device and deceleration motor |
| CN104421349A (en) * | 2013-08-20 | 2015-03-18 | 日本电产三协株式会社 | Friction mechanism and gear motor |
| CN108027163A (en) * | 2015-09-29 | 2018-05-11 | 日本电产三协株式会社 | Air guiding plate device |
| CN206694647U (en) * | 2017-03-30 | 2017-12-01 | 深圳市兰洋科技有限公司 | Angle valve handwheel closing device and its overload protecting mechanism |
| CN210927366U (en) * | 2018-10-26 | 2020-07-03 | 日本电产三协株式会社 | Overload protection mechanism and gear motor with same |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112910164A (en) * | 2021-01-22 | 2021-06-04 | 珠海格力电器股份有限公司 | Rotor shaft and motor |
| CN112910164B (en) * | 2021-01-22 | 2022-03-18 | 珠海格力电器股份有限公司 | Rotor shaft and motor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2020067168A (en) | 2020-04-30 |
| CN210927366U (en) | 2020-07-03 |
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Legal Events
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| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
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| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20200505 |