WO2016072453A1

WO2016072453A1 - Motor with speed reducer

Info

Publication number: WO2016072453A1
Application number: PCT/JP2015/081174
Authority: WO
Inventors: 吉田　浩之; 幹明小林
Original assignee: 株式会社ミツバ
Priority date: 2014-11-06
Filing date: 2015-11-05
Publication date: 2016-05-12
Also published as: JP6399899B2; JP2016093000A

Abstract

A protrusion (141) for locally increasing the dynamic pressure of a lubricant is provided at the maximum load position on the inner circumferential surface (4a) of a bearing metal (4) of an eccentric shaft, and/or on the cylindrical outer circumferential surface of the eccentric shaft.

Description

Reducer motor

The present invention relates to a motor with a reduction gear.
This application claims priority based on Japanese Patent Application No. 2014-225992 filed in Japan on November 6, 2014, the contents of which are incorporated herein by reference.

As a motor with a speed reducer, there is a motor with a speed reducer equipped with a speed reducer that operates by a hypocycloidal speed reduction method. This type of motor with a reduction gear includes a fixed shaft, a motor portion, an eccentric portion that is rotatably inserted into the fixed shaft, rotates by receiving the power of the motor portion, and rotates by the eccentric portion. A ring-shaped fixed gear fixed to a housing or the like and meshed with the external teeth of the rocking gear, and an output gear meshed with the internal teeth of the rocking gear and outputting power to the outside And. The eccentric portion has an eccentric outer peripheral surface centered at a position eccentric with respect to the center of the fixed shaft (rotation center of the motor portion), and a swing gear is inserted into the eccentric outer peripheral surface. The output gear is configured to rotate coaxially with the fixed shaft.

With this configuration, when the eccentric portion rotates as the motor unit is driven, the swinging gear performs a swinging motion (revolving motion) while meshing with the fixed gear and the output gear. Further, the oscillating gear performs a rotational motion at a rotational speed (spinning rotational speed) decelerated from the revolution rotational speed by meshing with the fixed gear. Then, the reduced rotational motion of the swing gear is transmitted to the output gear, and the output gear rotates at a rotational speed that is reduced more than the rotational speed of the motor unit.

Here, a meshing reaction force between the oscillating gear and the fixed gear and a meshing reaction force between the oscillating gear and the output gear are applied to the eccentric portion. In particular, since the fixed gear is fixed to the housing or the like, the eccentric portion is greatly affected by the meshing reaction force between the fixed gear and the oscillating gear. For this reason, the eccentric part is often rotatably supported on the fixed shaft via the rolling bearing. With this configuration, the energy loss of friction with respect to the fixed shaft of the eccentric portion can be minimized, and the rotational force of the motor portion can be efficiently transmitted to the oscillating gear.

JP 2014-81068 A

By the way, although it is an effective means to use a rolling bearing in order to minimize the energy loss of friction with respect to the fixed shaft of the eccentric part, the motor with a reduction gear is enlarged by the space for arranging this rolling bearing. End up. For this reason, it is conceivable to reduce the size of the motor with a reduction gear by using a sliding bearing instead of a rolling bearing, but simply replacing the rolling bearing with a sliding bearing will reduce the friction of the eccentric part against the fixed shaft. Energy loss will increase. For this reason, there exists a subject that the drive efficiency of the motor with a reduction gear will fall.

Therefore, the present invention provides a motor with a speed reducer that can suppress a reduction in drive efficiency while reducing the size of the motor with a speed reducer provided with a speed reducer that operates in a hypocycloid speed reduction system.

According to the first aspect of the present invention, the motor with a reduction gear is inserted into the motor unit, the fixed shaft provided at the rotation center of the motor unit, and the fixed shaft rotatably through the lubricant. An eccentric outer surface centered on an eccentric position that is eccentric with respect to the rotation center, and an eccentric portion that rotates by receiving the power of the motor unit, and the lubricant on the eccentric outer surface. And a fixed gear having a second internal tooth engaged with the first external tooth of the swing gear, and a swing gear having a first internal tooth and a first external tooth. An output gear having a second external tooth meshed with the first internal tooth of the rocking gear, rotating coaxially with the fixed shaft, and outputting power to an external device, The maximum position of the load applied to the fixed shaft on the inner peripheral surface, and the eccentricity To locally increase the dynamic pressure of the lubricant on the inner peripheral surface of the insertion hole and the eccentric outer peripheral surface at at least one of the maximum positions of the load applied to the rocking gear on the peripheral surface A wedge effect generator was provided.

By configuring as described above, an appropriate dynamic pressure of the lubricant can be generated at a desired position between the fixed shaft and the eccentric portion. For this reason, the energy loss of friction with respect to the fixed shaft of the eccentric part or the energy loss of friction with respect to the oscillating gear of the eccentric part can be reduced as much as possible without using a rolling bearing. Therefore, in a motor with a speed reducer provided with a speed reducer that operates in a hypocycloidal speed reduction method, a reduction in drive efficiency can be suppressed while downsizing the motor with a speed reducer.

According to the second aspect of the present invention, in the motor with a speed reducer according to the first aspect of the present invention, on the inner peripheral surface of the insertion hole, on a straight line connecting the rotation center and the eccentric position, The wedge effect generating portion is provided on the side opposite to the eccentric direction of the eccentric outer peripheral surface.

By configuring as described above, the wedge effect of the lubricating oil can be reliably generated at the maximum position of the load applied between the insertion hole of the eccentric portion and the fixed shaft. For this reason, the energy loss of friction with respect to the fixed shaft of an eccentric part can be reduced reliably.

According to a third aspect of the present invention, in the motor with a reduction gear according to the second aspect of the present invention, the inner peripheral surface of the insertion hole is an inner peripheral surface of a slide bearing provided in the eccentric portion. The wedge effect generating portion is provided on the inner peripheral surface.

By configuring as described above, the energy loss of friction with respect to the fixed shaft of the eccentric portion can be more reliably reduced.

According to a fourth aspect of the present invention, in the motor with a reduction gear according to any one of the first to third aspects of the present invention, the eccentric outer peripheral surface includes the rotation center and the eccentricity. The wedge effect generating portion is provided on a straight line connecting the positions and on the eccentric direction side of the eccentric outer peripheral surface.

By configuring as described above, the wedge effect of the lubricating oil can be reliably generated at the maximum position of the load applied between the eccentric outer peripheral surface of the eccentric portion and the swing gear. For this reason, the energy loss of the friction with respect to the rocking | fluctuation gear of an eccentric part can be reduced reliably.

According to a fifth aspect of the present invention, in the motor with a reduction gear according to any one of the first to fourth aspects of the present invention, the wedge effect generating portion is formed along the axial direction. It is the projected ridge part.

By configuring as described above, the wedge effect of the lubricating oil can be generated over the entire axial direction of a desired location.

According to a sixth aspect of the present invention, in the motor with a speed reducer according to the fifth aspect of the present invention, the convex strip portion has an arcuate cross-sectional shape along a direction orthogonal to the axial direction. Is formed.

By configuring as described above, the wedge effect of the lubricating oil can be efficiently generated by the ridges.

According to the motor with a reduction gear described above, an appropriate dynamic pressure of the lubricant can be generated at a desired position between the fixed shaft and the eccentric portion. For this reason, the energy loss of friction with respect to the fixed shaft of the eccentric part or the energy loss of friction with respect to the oscillating gear of the eccentric part can be reduced as much as possible without using a rolling bearing. Therefore, in a motor with a speed reducer provided with a speed reducer that operates in a hypocycloidal speed reduction method, a reduction in drive efficiency can be suppressed while downsizing the motor with a speed reducer.

It is sectional drawing of the motor with a reduction gear in embodiment of this invention. It is a perspective view of the motor part in the embodiment of the present invention. It is a disassembled perspective view of the motor part in embodiment of this invention. It is a perspective view of a commutator in an embodiment of the present invention. It is a perspective view which shows the state which attached the resin boss | hub member to the armature core in embodiment of this invention. It is a perspective view of the eccentric shaft in the embodiment of the present invention. It is the top view which looked at the eccentric shaft in embodiment of this invention from the bottom. It is the top view which looked at the eccentric shaft in embodiment of this invention from the top. It is the top view which looked at the bearing metal in 1st Embodiment of this invention from the axial direction. It is a perspective view of the bearing metal in 1st Embodiment of this invention. It is a perspective view of the electric power feeder in embodiment of this invention. It is a disassembled perspective view of the deceleration mechanism part in embodiment of this invention. It is a top view which shows the meshing state of the ring gear in the embodiment of this invention, a rocking | fluctuation gear, and an output gear. It is explanatory drawing for demonstrating the position of the protruding item | line part in 1st Embodiment of this invention. It is a graph which shows the change of the bearing load capacity of the bearing metal in 1st Embodiment of this invention. It is explanatory drawing for demonstrating the formation position of the protruding item | line part in 2nd Embodiment of this invention.

Next, an embodiment of the present invention will be described based on the drawings.

(First embodiment)
(Motor with reduction gear)
FIG. 1 is a cross-sectional view of a motor 1 with a speed reducer.
As shown in FIG. 1, the motor 1 with a speed reducer is a flat motor unit 10 configured as a DC brush motor, and the rotational output of the motor unit 10 is decelerated and output from an output shaft (output gear) 110. And a reduction mechanism 100 configured as a hypocycloid reduction mechanism.

FIG. 2 is a perspective view of the motor unit 10, and FIG. 3 is an exploded perspective view of the motor unit 10.
As shown in FIGS. 1 to 3, the motor axis L that is the rotation center of the motor unit 10 (the rotation center of an armature described later) coincides with the rotation center (axis) of the output shaft 110.
In the following description, the side from which output is extracted from the output shaft 110 will be referred to as the upper side (upper side in FIG. 1), and the opposite side will be referred to as the lower side (lower side in FIG. 1).

The motor 1 with a speed reducer includes a motor housing 11 having a bottom wall 11a and a peripheral wall 11b as an outer shell, and a speed reduction mechanism unit cover 101 coupled to the motor housing 11. And almost all the mechanism elements are accommodated in the space surrounded by the motor housing 11 and the speed reduction mechanism section cover 101.

A cylindrical yoke 12 is disposed on the inner peripheral surface of the peripheral wall 11b of the motor housing 11, and a motor magnet (permanent magnet) 13 is disposed in a cylindrical shape on the inner peripheral surface of the yoke 12. The motor magnet 13 is formed by alternately arranging a plurality (for example, six in this embodiment) of magnetic poles (N poles and S poles) formed on the inner peripheral surface in the circumferential direction.

Here, a stator is constituted by the yoke 12 and the motor magnet 13, and an armature 20 that is rotatable around the motor axis L is disposed on the inner peripheral side of the motor magnet 13. In addition, a power supply device 40 including a pair of brushes 45 for supplying power to the armature 20 is disposed on the upper side of the armature 20.
The motor magnet 13 may be formed in a cylindrical shape, or may be arranged in a tile shape along the circumferential direction.

The substantially cylindrical main shaft member 2 is erected on the bottom wall 11a of the motor housing 11 at the center in the radial direction. As for the main shaft member 2, the base end 2a is being fixed to the center support part 11c of the bottom wall 11a. The main shaft member 2 passes through the center in the radial direction of the armature 20, and the tip 2 b projects from the opening in the center in the radial direction of the speed reduction mechanism unit cover 101. That is, the main shaft member 2 is set so that the center line is coaxial with the motor axis L. In addition, as a material of the main shaft member 2, various materials such as iron, stainless steel, aluminum alloy, and resin can be selected.

(Armature)
The armature 20 that is the main element of the motor unit 10 is disposed coaxially with the main shaft member 2 and is disposed in the motor housing 11 so as to surround the main shaft member 2.
As shown in FIGS. 2 and 3, the armature 20 includes an armature core 21, lower and

upper insulators

22 and 23, an armature coil 24, and a commutator 30.

(Armature core)
As shown in FIG. 3, the armature core 21 is configured by laminating a plurality of steel plates press-formed in the same shape in the axial direction. The armature core 21 has a substantially annular core body 21a, and a plurality of teeth 21b having a substantially T-shape in a plan view in the axial direction are radially arranged at equal intervals in the circumferential direction on the radially outer side of the core body 21a. For example, in this embodiment, 9). The teeth 21b include a collar portion 21bt that is formed at the tip portion and extends along the circumferential direction. The teeth 21b are substantially T-shaped in the plan view in the axial direction by the flange 21bt.

Further, a slot 21s is formed between adjacent teeth 21b. An enamel-wrapped winding W is passed through the slot 21s, and the winding W is wound around the teeth 21b in a concentrated manner from above the

insulators

22 and 23 attached to the teeth 21b. Thereby, a plurality of armature coils 24 are formed on the outer peripheral surface of the armature core 21.

Furthermore, a circular center opening 21c is provided in the center of the core body 21a. On the inner peripheral surface of the center opening 21c, core-side concave portions 21d and core-side convex portions 21e are alternately arranged in the circumferential direction so as to penetrate in the axial direction. The core-side concave portion 21d and the core-side convex portion 21e have the same pitch as the teeth 21b, the core-side concave portion 21d is aligned with the tooth 21b, and the core-side convex portion 21e is aligned with the slot 21s. Are arranged. The core-side concave portion 21d and the core-side convex portion 21e have a function of preventing a relative position shift between the armature core 21 and the commutator 30 (details will be described later).

(Insulator)
The lower insulator 22 and the upper insulator 23 are formed of an insulating resin, and are mounted from above and below the armature core 21, respectively. In a state where the

insulators

22 and 23 are mounted on the armature core 21, these

insulators

22 and 23 cover most portions except for the outer peripheral surface of the tip of the teeth 21 b of the armature core 21.

The lower insulator 22 and the upper insulator 23 have the same shape. Here, the shape of the upper insulator 23 will be briefly described, and the description of the lower insulator 22 will be omitted.
The axial end surface of the teeth 21b of the armature core 21 in the upper insulator 23, that is, the upper surface 23a of the upper insulator 23 in FIGS. 1 to 3 is a surface around which the winding W constituting the armature coil 24 is wound. The upper surface 23a of the upper insulator 23 is formed as a flat surface throughout. In the center of the upper surface 23a, a circular central opening 23b is provided so as to correspond to the central opening 21c of the armature core 21. Further, the upper insulator 23 is formed with a hook 28 for hooking the connecting wire of the winding W spanning between the teeth 21b, thereby preventing the connecting wire from entering inward in the radial direction.

(Commutator)
FIG. 4 is a perspective view of the commutator 30.
As shown in FIGS. 3 and 4, the commutator 30 includes a cylindrical resin boss member 31 made of an insulating resin, and a plurality of (for example, nine in this embodiment) segments attached to the resin boss member 31. And a metal piece 32.

The lower half (base) of the resin boss member 31 is configured as a press-fitting fitting portion 33 that is press-fitted into the circular central opening 21c of the armature core 21, and a cylindrical wall 35 is provided on the upper side thereof. Yes. The outer diameter of the press-fit fitting portion 33 is set to be about twice as large as the outer diameter of the cylindrical wall 35.
On the outer peripheral surface of the press-fit fitting portion 33, a boss-side convex portion 33a that fits into the core-side concave portion 21d of the armature core 21 and a boss-side concave portion 33b that fits into the core-side convex portion 21e of the armature core 21 are teeth 21b. Are formed at the same pitch.

Further, a flange 34 larger than the outer diameter of the press-fit fitting portion 33 is provided at the boundary between the press-fit fitting portion 33 and the cylindrical wall 35. The outer diameter of the flange 34 is set to a size that fits on the inner periphery of the central opening 23 b of the upper insulator 23. In addition, although there is a change in the outer diameter in the axial direction, a straight cylindrical surface having the same diameter is formed between the inner peripheral surface 35a of the cylindrical wall 35 of the resin boss member 31 and the inner peripheral surface 31a of the press-fitting fitting portion 33. It is continuous.

FIG. 5 is a perspective view showing a state in which the resin boss member 31 is attached to the armature core 21.
As shown in FIGS. 3 and 5, the resin boss member 31 is press-fitted (internally fitted) into the center opening 21 c of the armature core 21 so that the outer peripheral surface of the press-fit fitting portion 33 is coaxial with the armature core 21. Fixed). At this time, the armature core 21 and the resin boss member 31 are positioned in the radial direction by press-fitting the bottom surface 21ds of the core-side concave portion 21d and the top surface 33at of the boss-side convex portion 33a. And the shift | offset | difference of the relative position of the armature core 21 and the commutator 30 is prevented.

Further, as shown in FIG. 1, the inner peripheral surface 31 a of the resin boss member 31 is rotatably fitted to the outer peripheral surface of the main shaft member 2 via the bearing metal 3. Therefore, the armature 20 is supported so as to be rotatable around the motor axis L coaxial with the main shaft member 2.
Further, when the lower press-fitting fitting portion 33 of the flange 34 is fitted into the central opening 21 c of the armature core 21, the lower surface of the flange 34 abuts on the axial end surface (upper surface) of the armature core 21. Thereby, the resin boss member 31 is positioned in the axial direction.

(Segment metal piece)
As shown in FIGS. 1, 4, and 5, each segment metal piece 32 includes an arcuate cylindrical segment 32 a in which the brush 45 is in sliding contact with a riser 32 b formed by bending the segment 32 a into an L shape. Is formed. The segment 32 a is disposed on the outer peripheral surface of the cylindrical wall 35 of the resin boss member 31 protruding in the axial direction from the armature core 21 with the brush contact surface facing radially outward. And they are arranged side by side at a constant pitch while being insulated from each other in the circumferential direction.
The same number of segments 32a and risers 32b as the number of teeth 21b are provided, and the segments 32a and risers 32b are arranged on the center line in the width direction of the teeth 21b. In other words, the teeth 21b and the riser 32b are arranged such that the center line in the width direction of the teeth 21b and the center line in the width direction of the riser 32b are located on the same straight line along the radial direction.

The riser 32 b is a hooking portion that connects the lead wire (winding W) of the armature coil 24, and is mounted and fixed on the riser arrangement surface set on the upper surface 34 a of the flange 34 of the resin boss member 31. The upper surface 34 a of the flange 34 on which the riser arrangement surface is set is formed as a plane orthogonal to the outer peripheral surface of the cylindrical wall 35. When the resin boss member 31 is press-fitted into the armature core 21 (see FIG. 5), it is configured to be flush with the upper surface 23a of the upper insulator 23.
Further, the tip of the riser 32b is folded upward in a U-shape so that the end of the armature coil 24 (end of the winding W) can be easily connected. The length of the folded portion of the riser 32b is set to a length that allows two or more electric wires to be hooked.

(Eccentric shaft)
Next, the eccentric shaft 120 connected to the commutator 30 and constituting the speed reduction mechanism 100 will be described with reference to FIGS. 2, 4, and 6A to 6C.
FIG. 6A is a perspective view of the eccentric shaft 120. FIG. 6B is a plan view of the eccentric shaft 120 as viewed from below. FIG. 6C is a plan view of the eccentric shaft 120 as viewed from above.
As shown in FIGS. 2, 4, and 6A to 6C, the eccentric shaft 120 is connected to the tip of the cylindrical wall 35 of the resin boss member 31 of the commutator 30 in a relatively non-rotatable manner. The eccentric shaft 120 includes an eccentric rotating part 121 and three fitting convex parts 122 for transmitting rotational force that are provided on the lower surface of the eccentric rotating part 121.

The eccentric shaft 120 is formed in a cylindrical shape as a whole, and the inner peripheral surface 121b of the insertion hole penetrating in the axial direction is formed as a cylindrical surface with the motor axis L as the center. The outer peripheral surface of the eccentric rotating portion 121 is formed as a cylindrical outer peripheral surface 121a having a center O2 at a position eccentric with respect to the center O1 concentric with the motor axis L. Therefore, the cylindrical outer peripheral surface 121a of the eccentric rotating part 121 rotates eccentrically with respect to the motor axis L (center O1).

The three fitting convex portions 122 are formed by providing three notches on a cylindrical wall concentric with the motor axis L, and are arranged at intervals of 120 ° in the circumferential direction.
In addition, the number of fitting convex parts 122 is not restricted to three, One may be sufficient and three or more may be sufficient. Further, the arrangement interval of the fitting convex portions 122 is not limited to 120 °.

Of the three fitting convex portions 122, one fitting convex portion 122 is arranged with the center in the width direction aligned at a position diametrically opposite to the eccentric direction H, and two positions separated from each other by 120 ° in the opposite direction. In addition, the remaining two fitting projections 122 are arranged. These fitting projections 122 are formed by a divisor (3) of the number (9) of the segments 32a and teeth 21b. Here, as shown in FIG. 4, the eccentric shaft 120 has an eccentric direction so that a subtle eccentric direction H can be easily seen on the surface 12 c opposite to the fitting convex portion 122 of the eccentric rotating portion 121. A mark 125 indicating H is provided. Note that the mark mark 125 may not be provided.

On the other hand, at the tip of the cylindrical wall 35 of the resin boss member 31, three fitting recesses 36 into which the fitting projections 122 of the eccentric shaft 120 are fitted are provided. The fitting convex part 122 on the eccentric shaft 120 side and the fitting concave part 36 on the resin boss member 31 side prevent relative rotation of each other and transmit the rotational force.

(Bearing metal)
As shown in FIGS. 1 and 4, the bearing metal 4 is press-fitted into the inner peripheral surface 121 b of the eccentric shaft 120. The bearing metal 4 is provided over the entire axial direction of the eccentric rotating part 121 and the fitting convex part 122. A part of the bearing metal 4 exposed from between the fitting protrusions 122 adjacent in the circumferential direction is press-fitted into the inner peripheral surface 31 a of the resin boss member 31. Thereby, the resin boss member 31 and the eccentric shaft 120 are centered.
Further, the eccentric shaft 120 and the resin boss member 31 are rotatably supported by the main shaft member 2 through the bearing metal 4. A lubricant (not shown) is applied between the bearing metal 4 and the main shaft member 2 so as to reduce the frictional resistance generated between the bearing metal 4 and the main shaft member 2.

FIG. 7A is a plan view of the bearing metal 4 as seen from the axial direction. FIG. 7B is a perspective view of the bearing metal 4.
As shown in FIGS. 7A and 7B, a convex strip 141 is integrally formed on the inner peripheral surface 4 a of the bearing metal 4 over the entire axial direction. The ridge 141 is for locally increasing the dynamic pressure of the lubricant applied between the bearing metal 4 and the main shaft member 2. The ridge 141 is formed so that the cross-sectional shape orthogonal to the axial direction has an arcuate surface 141a. In other words, the ridge 141 is formed in a substantially bowl shape. In addition, the specific formation position and dimension of the protruding item | line part 141 are mentioned later.

(Power supply device, brush)
Next, the power feeding device 40 will be described based on FIGS. 1 and 8.
FIG. 8 is a perspective view of the power feeding device 40.
As shown in FIGS. 1 and 8, the power feeding device 40 has a substantially disc-shaped power feeding housing 41 formed of an insulating resin. The power supply housing 41 is provided with a brush 45 and a spring 43 via a brush holder 42. The brush 45 is electrically connected to a terminal of a connector 48 provided on the power supply housing 41.

Further, the brush 45 is disposed on the outer peripheral side of the cylindrical wall 35 of the resin boss member 31 of the commutator 30 and at an upper position adjacent to the axial direction of the armature core 21. The brush 45 is in sliding contact with the brush contact surface of the armature 20 facing the radially outward direction of the segment 32a from the radially outward direction toward the radially inward direction. Further, the spring 43 acts on the brush 45 by a biasing force toward the brush contact surface of the segment 32a.

(Deceleration mechanism)
Next, the speed reduction mechanism 100 will be described with reference to FIGS. 1, 9, and 10.
FIG. 9 is an exploded perspective view of the speed reduction mechanism unit 100.
As shown in FIGS. 1 and 9, the speed reduction mechanism 100 is disposed so as to surround a position corresponding to the tip 2 b of the main shaft member 2. An output shaft 110 formed in an annular shape surrounds the main shaft member 2 and is arranged coaxially with the motor axis L.

The speed reduction mechanism unit 100 is configured as a hypocycloid speed reduction mechanism. In addition to the eccentric shaft 120 described above, the speed reduction mechanism unit 100 includes a ring gear 102 fixed to the inner peripheral surface of the speed reduction mechanism unit cover 101, and a swing attached to the eccentric shaft 120. The moving gear 103 and the output gear 104 formed integrally with the lower end of the output shaft 110 having the cylindrical boss 111 are included.

The ring gear 102 has an inner tooth 102 a concentric with the motor axis L.
The oscillating gear 103 is formed by integrally molding a substantially disk-shaped external gear portion 203 and a ring-shaped internal gear portion 303 integrally formed on the external gear portion 203. External teeth 203 a that can mesh with the internal teeth 102 a of the ring gear 102 are formed on the outer peripheral surface of the external gear portion 203. On the inner peripheral surface of the internal gear portion 303, internal teeth 303a that can mesh with external teeth 104a described later of the output gear 104 are formed.

Further, the outer gear portion 203 is formed with a bearing hole 203b substantially at the center in the radial direction. A cylindrical outer peripheral surface 121a of the eccentric rotating portion 121 of the eccentric shaft 120 is rotatably fitted in the bearing hole 203b via the bearing metal 6. Therefore, the oscillating gear 103 is supported so as to revolve around the motor axis L and to rotate around the center O2 (see FIG. 6B) of the cylindrical outer peripheral surface 121a of the eccentric shaft 120.

The output shaft 110 is rotatably supported by the main shaft member 2 and the speed reduction mechanism unit cover 101 via a bearing metal 5 provided on the inner peripheral side and a bearing metal 7 provided on the outer peripheral side.
A substantially disc-shaped output gear 104 is integrally formed at the lower end of such an output shaft 110. The output gear 104 is provided concentrically with the motor axis L, and outer teeth 104 a that can mesh with the inner teeth 303 a of the swing gear 103 are formed on the outer peripheral surface.
The bearing metals 4 to 6 are each made of an iron-based material, a copper alloy, an aluminum alloy, brass, or the like. Further, lubricant is applied to the bearing metals 5 and 7 provided on the output shaft 110 and the bearing metal 6 provided on the external gear portion 203, respectively.

FIG. 10 is a plan view showing a meshing state of the ring gear 102, the swing gear 103, and the output gear 104. FIG.
As shown in the figure, the meshing point PA between the internal teeth 102a of the ring gear 102 and the external teeth 203a of the swing gear 103, and the meshing point PB of the internal teeth 303a of the swing gear 103 and the external teeth 104a of the output gear 104 are as follows. The position is the opposite side across the motor axis L. In other words, since the center of the oscillating gear 103 is decentered by the eccentric shaft 120, on the straight line S1 connecting the center O2 of the cylindrical outer peripheral surface 121a of the eccentric shaft 120 and the motor axis L (center O1). The meshing points PA and PB are located on both sides of the motor axis L, respectively.

With the above-described configuration, in the motor 1 with a speed reducer, when power is supplied to the armature coil 24 via the brush 45 and the segment 32a, a predetermined magnetic field is generated in the armature core 21. A magnetic attractive force or a repulsive force acts between the magnetic field and the motor magnet 13 to rotate the armature 20. By this rotation, the segments 32a with which the brush 45 is in sliding contact are sequentially changed, so that the direction of the current flowing through the armature coil 24 is switched, so-called rectification is performed, and the armature 20 is continuously rotated.

When the armature 20 rotates, the eccentric shaft 120 integrated with the commutator 30 rotates. Then, the oscillating gear 103 performs an oscillating motion (revolving motion) while meshing with the ring gear 102 and the output gear 104. Further, the oscillating gear 103 rotates with a rotational speed (spinning rotational speed) decelerated from the revolution rotational speed by meshing with the ring gear 102. Then, the reduced rotational motion of the swing gear 103 is transmitted to the output gear 104, and the output gear 104 rotates at a rotational speed that is decelerated from the rotational speed of the armature 20. Then, power is output to an external device (not shown) via the output shaft 110.

(Position and dimension of bearing metal ridges)
Next, based on FIG. 7A, FIG. 7B, and FIG. 11, the position and specific dimension of the convex strip part 141 of the bearing metal 4 provided between the main shaft member 2 and the eccentric shaft 120 will be described.
FIG. 11 is an explanatory diagram for explaining the position of the ridge portion 141.
Here, as described above, the meshing point PA between the internal teeth 102 a of the ring gear 102 and the external teeth 203 a of the swing gear 103, and the meshing point PB of the internal teeth 303 a of the swing gear 103 and the external teeth 104 a of the output gear 104. Are located on both sides of the motor axis L on a straight line S1 connecting the center O2 of the cylindrical outer peripheral surface 121a of the eccentric shaft 120 and the motor axis L (center O1).

For this reason, a maximum load is always applied to the bearing metal 4 at the position P1 on the straight line S1 and on the opposite side to the eccentric direction of the cylindrical outer peripheral surface 121a. Since the bearing metal 4 is press-fitted into the inner peripheral surface 121b of the eccentric shaft 120, the maximum load position on the bearing metal 4 does not change even when the eccentric shaft 120 rotates. Therefore, by providing the convex portion 141 at the position P1 of the bearing metal 4, the dynamic pressure of the lubricant on the front side in the rotational direction of the convex portion 141 is locally increased (the wedge effect of the lubricant is generated). Can do.

Here, as shown in FIG. 7A, when the width of the ridge 141 is W, the protrusion height is h, the radius of curvature of the arcuate surface 141a is r, and the shaft diameter of the main shaft member 2 is d, the curvature is The radius ratio r ′ (= r / d) and the width ratio W ′ (= w / d) are 0.1 ≦ r ′ ≦ 7.2 (1)
0.002 ≦ W ′ ≦ 0.16 (2)
It is set to satisfy. By satisfying the formulas (1) and (2), the ridges 141 are completely crushed so that the wedge effect does not occur, or the ridges 141 are too large and the bearing metal 4 and the main shaft member 2 It is possible to prevent the proper lubricant film from being formed in the meantime.

In addition, the ridge 141 is
0.007 ≦ h / W ≦ 1.08 (3)
It is formed to satisfy.
Desirably, the ridge 141 is
0.007 ≦ h / W ≦ 0.5 (4)
It is good to be formed so as to satisfy.
Furthermore, desirably, the convex strip 141 is
0.015 ≦ h / W ≦ 0.05 (5)
It is good to be formed so as to satisfy.
Formula (3) to Formula (5) will be described in detail below.

FIG. 12 shows the bearing load capacity of the bearing metal 4 when the vertical axis is the bearing load capacity of the bearing metal 4 and the horizontal axis is the ratio (h / W) between the protruding height h and the width W of the protrusion 141. It is a graph which shows the change of.
As shown in the figure, when the ridge portion 141 is formed so as to satisfy the expression (3), the ridge portion 141 is completely crushed and does not generate a wedge effect. It is possible to prevent the clearance between the bearing 2 and the bearing metal 4 from being properly maintained.

Furthermore, when the protruding strip 141 is formed so as to satisfy the formula (4), the bearing metal 4 can generate a good rust effect with respect to the rated load of the motor 1 with a reduction gear.
Furthermore, when the convex strip 141 is formed so as to satisfy the formula (5), the bearing metal 4 can generate a good rust effect even when the motor 1 with a speed reducer is overloaded. it can.

Thus, in said 1st Embodiment, in the motor 1 with a reduction gear provided with the reduction mechanism part 100 comprised as a hypocycloid reduction mechanism, the bearing metal provided between the main shaft member 2 and the eccentric shaft 120 is provided. 4 is provided with a ridge 141. And this protruding item | line part 141 is arrange | positioned in the largest position of the load concerning the bearing metal 4, ie, the position P1 on the opposite side to the eccentric direction of the cylindrical outer peripheral surface 121a on the straight line S1 shown in FIG. . For this reason, the wedge effect by the lubricant can be efficiently generated between the main shaft member 2 and the bearing metal 4 and at the position where the dynamic pressure of the lubricant is most desired. As a result, the energy loss of friction with respect to the main shaft member 2 of the eccentric shaft 120 can be reduced as much as possible without using a rolling bearing as in the prior art. Therefore, a reduction in drive efficiency can be suppressed while reducing the size of the motor 1 with a reduction gear as compared with the case where a rolling bearing is used.

Moreover, the protruding item | line part 141 is formed over the whole axial direction. For this reason, the wedge effect by the lubricant can be generated over the entire axial direction of the bearing metal 4.
Furthermore, the protruding portion 141 is formed so that the cross-sectional shape orthogonal to the axial direction has an arcuate surface 141a. In other words, the ridge 141 is formed in a substantially bowl shape. For this reason, the protruding portion 141 can efficiently generate the wedge effect of the lubricating oil.

(Second Embodiment)
Next, a second embodiment will be described based on FIG.
FIG. 13 is an explanatory diagram for explaining the formation position of the ridge 141 in the second embodiment, and corresponds to FIG. 11 described above.
Here, the difference between said 1st Embodiment and 2nd Embodiment exists in the point from which the formation position of the protruding item | line part 141 differs. In other aspects, the first embodiment and the second embodiment described above are the same, and therefore, the same reference numerals are given to the respective parts and the description thereof is omitted.

As shown in FIG. 13, the protrusion 141 for generating the wedge effect of the lubricating oil is not provided on the bearing metal 4 and is integrally formed on the cylindrical outer peripheral surface 12 a of the eccentric shaft 120. Further, the ridge 141 is arranged on a straight line S1 connecting the center O2 of the cylindrical outer peripheral surface 121a of the eccentric shaft 120 and the motor axis L (center O1) and on the eccentric direction side of the cylindrical outer peripheral surface 121a.

Here, as described in the first embodiment (particularly, FIG. 10), the meshing point PA between the inner teeth 102 a of the ring gear 102 and the outer teeth 203 a of the oscillating gear 103 and the inner teeth of the oscillating gear 103. The meshing point PB of 303a and the external gear 104a of the output gear 104 is on both sides of the motor axis L on a straight line S1 connecting the center O2 of the cylindrical outer peripheral surface 121a of the eccentric shaft 120 and the motor axis L (center O1). positioned. For this reason, a maximum load is always applied to the cylindrical outer peripheral surface 121a on the straight line S1 and in the eccentric direction of the cylindrical outer peripheral surface 121a. Therefore, the energy loss due to the friction between the eccentric shaft 120 and the oscillating gear 103 can be reduced as much as possible by providing the ridge 141 at the position where the maximum load is applied.
Therefore, according to said 2nd Embodiment, there can exist an effect similar to the above-mentioned 1st Embodiment.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the ridge 141 is formed such that the cross-sectional shape orthogonal to the axial direction has the arcuate surface 141a, in other words, the ridge 141 is formed in a substantially bowl shape. Explained. However, the shape is not limited to this, and any shape that can obtain a wedge effect by the lubricant may be used. However, when the ridge 141 is formed in a quadrangular cross section, the wedge effect by the lubricant cannot be greatly obtained as compared with the ridge-shaped ridge 141. In addition, the spherical bodies may be arranged in the axial direction on the cylindrical outer peripheral surface 121a of the bearing metal 4 or the eccentric shaft 120 in place of the ridge 141. Even when configured in this manner, the same effects as those of the above-described embodiment can be obtained.

Further, in the above-described embodiment, a case has been described in which the convex strip 141 is integrally formed on the cylindrical outer peripheral surface 121a of the bearing metal 4 or the eccentric shaft 120. However, it is not restricted to this, You may provide the protruding item | line part 141 separately.
Furthermore, in said 1st Embodiment, the protruding item | line part 141 was provided in the bearing metal 4, and the case where the protruding item | line part 141 was provided in the cylindrical outer peripheral surface 121a of the eccentric shaft 120 was demonstrated in 2nd Embodiment. However, the present invention is not limited to this, and the first embodiment and the second embodiment may be combined. That is, the ridge 141 may be provided on each of the bearing metal 4 and the cylindrical outer peripheral surface 121a of the eccentric shaft 120.

In the first embodiment described above, the case where the protruding strip 141 is provided on the bearing metal 4 provided on the eccentric shaft 120 has been described. However, without providing the bearing metal 4, the convex strip 141 is provided directly on the inner peripheral surface 121 b of the eccentric shaft 120, and the lubricant is applied between the inner peripheral surface 121 b and the main shaft member 2. Also good.

Further, in the above-described embodiment, the oscillating gear 103 and the output gear 104 are transmitted with the engagement between the internal teeth 303 a formed on the internal gear portion 303 of the oscillating gear 103 and the external teeth 104 a of the output gear 104. The structure to be explained was explained. However, the present invention is not limited to this. For example, a plurality of pins are concentrically arranged in the output gear 104, and a swing hole having the same number as the pins and larger in diameter than the outer diameter of the pins is provided in the swing gear 103. By forming concentric circles, the pin of the output gear 104 may be inserted into the swing hole of the swing gear 103.

1 Motor with reduction gear 2 Main shaft member (fixed shaft)
4 Bearing metal (sliding bearing)
4a Inner peripheral surface 10 Motor part 102 Ring gear (fixed gear)
102a Internal teeth (second internal teeth)
103 Oscillating gear 104 Output gear 104a External teeth (second external teeth)
120 Eccentric shaft (Eccentric part)
121a Cylindrical outer peripheral surface (eccentric outer peripheral surface)
141 ridge 141a arcuate surface 203a external teeth (first external teeth)
303a Internal teeth (first internal teeth)
S1 straight line

Claims

A motor section;
A fixed shaft provided at the rotation center of the motor unit;
The fixed shaft has an insertion hole that is rotatably inserted through a lubricant, has an eccentric outer peripheral surface centered on an eccentric position that is eccentric with respect to the rotation center, and receives the power of the motor unit. A rotating eccentric part;
An oscillating gear that is rotatably inserted into the eccentric outer peripheral surface via the lubricant, and has first internal teeth and first external teeth;
A fixed gear having second internal teeth meshed with the first external teeth of the swing gear;
An output gear having second external teeth meshed with the first internal teeth of the swing gear, rotating coaxially with the fixed shaft, and outputting power to an external device;
With
At least one of the maximum position of the load applied to the fixed shaft on the inner peripheral surface of the insertion hole and the maximum position of the load applied to the swing gear on the eccentric outer peripheral surface is the insertion hole. A motor with a reduction gear provided with a wedge effect generating portion for locally increasing the dynamic pressure of the lubricant on the inner peripheral surface and the eccentric outer peripheral surface.
The wedge effect generating portion is provided on an inner peripheral surface of the insertion hole on a straight line connecting the rotation center and the eccentric position, and on a side opposite to an eccentric direction of the eccentric outer peripheral surface. The motor with a reduction gear according to 1.
The motor with a reduction gear according to claim 2, wherein an inner peripheral surface of the insertion hole is an inner peripheral surface of a sliding bearing provided in the eccentric portion, and the wedge effect generating portion is provided on the inner peripheral surface. .
The wedge effect generating portion is provided on the eccentric outer peripheral surface, on a straight line connecting the rotation center and the eccentric position, and on an eccentric direction side of the eccentric outer peripheral surface. The motor with a reduction gear according to any one of the above.
The motor with a speed reducer according to any one of claims 1 to 4, wherein the wedge effect generating portion is a ridge formed along an axial direction.
The motor with a speed reducer according to claim 5, wherein the protruding portion is formed such that a cross-sectional shape along a direction orthogonal to the axial direction has an arcuate surface.