JPH1051999A - Geared motor adopting inner-gearing planetary gear structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the axial direction dimension of a geared motor adopting an inner-gearing planetary gear structure. SOLUTION: This geared motor has a reduction mechanism part 120 which is provided with the following; an input shaft 101, an eccentric body 103 formed on the input shaft 101, an external gear 105 fixed to the input shaft 102 via the eccentric body 103, in the state capable of eccentric rotation to the input shaft 101, an internal gear 110 with which the external gear 105 inner-gears, and an output shaft 102 transmitted to the external gear 105 via a means which transmits only the rotation component of the external gear 105. A balance weight 130 for adjusting the load balance when the external gear rocks is installed in a vacant space of the motor 122.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a geared motor employing an internally meshing planetary gear structure.

[0002]

2. Description of the Related Art Conventionally, a first shaft, an eccentric body provided on the first shaft, and an external gear mounted eccentrically rotatable with respect to the first shaft via the eccentric body, An internally meshing planetary gear structure having an internal gear in which the external gear internally meshes and a second shaft connected to the external gear via means for transmitting only the rotation component of the external gear is widely used. Are known.

FIGS. 10 and 11 show a conventional example of this structure. In this conventional example, the first shaft is used as an input shaft, the second shaft is used as an output shaft, and the above structure is applied to a "reduction gear" by fixing an internal gear.

Further, the "reduction gear" is combined with a motor to form a geared motor.

[0005] An eccentric body 3 is fitted to the input shaft 1.
An external gear 5 is mounted on the eccentric body 3 via a bearing 4. The external gear 5 is provided with a plurality of inner roller holes 6, and an inner pin 7 and an inner roller 8 are fitted therein.

[0006] On the outer periphery of the external gear 5, external teeth 9 such as a trochoid tooth shape and an arc tooth shape are provided. The external teeth 9 are internally meshed with an internal gear 10 fixed to a casing 12. Specifically, the internal teeth of the internal gear 10 have a structure in which the outer pin 11 is loosely fitted in the outer pin hole 13 and held so as to be easily rotated.

The inner pin 7 penetrating the external gear 5 is fixed or fitted to the flange portion 14 of the output shaft 2.

When the input shaft 1 makes one rotation, the eccentric body 3 makes one rotation. By one rotation of the eccentric body 3, the external gear 5 also attempts to oscillate around the input shaft 1.
As a result, the rotation of the external gear 5 is almost limited while the internal gear 10 is in contact with the internal gear 10.

For example, if the number of teeth of the external gear 5 is N and the number of teeth of the internal gear 10 is N + 1, the difference in the number of teeth is 1. Therefore, each time the input shaft 1 rotates, the external gear 5 shifts (rotates) by one tooth with respect to the internal gear 10 fixed to the casing 12. This is input shaft 1
This means that the rotation has been reduced to -1 / N rotation of the external gear.

The rotation of the external gear 5 is absorbed by the gap between the inner roller hole 6 and the inner pin 7, and only the rotation component is transmitted to the output shaft 2 via the inner pin 7.

Here, the inner roller hole 6 and the inner pin 7
The (inner roller 8) forms a “constant-speed internal gear mechanism”.

As a result, the reduction of the reduction ratio -N is achieved.

Therefore, by combining the motor 22 with the reduction mechanism 20 employing the internal meshing planetary gear structure, a single-stage geared motor having a large reduction ratio can be obtained with only one reduction gear.

That is, the motor shaft 24 and the input shaft 1 are integrated, and the rotation of the motor 22 is greatly reduced by the speed reduction mechanism 20 and is taken out from the output shaft 2.

[0015] Integrated input shaft 1 and motor shaft 24
Is held by three bearings 26, 27, 28.
At this time, a centrifugal force due to the eccentric rotation of the eccentric body 3 and a load due to the swinging of the external gear 5 are applied to the input shaft 1 and the motor shaft 24. This load is received by the bearings 26, 27, and 28. The input shaft 1 and the motor shaft 24 bend and vibrate due to the load.

A balance weight 30 is provided to adjust the load balance and suppress this vibration (axis run-out).

Conventionally, as shown in FIG. 10, the balance weight 30 is provided on the input shaft 1 immediately next to the eccentric body 3 in the speed reduction mechanism section 20 by a predetermined phase difference (for example, 180 °) from the eccentric body 3.
It was installed with.

[0018]

As described above, conventionally, since the balance weight is disposed in the speed reduction mechanism, the axial length of the geared motor is increased by the width of the balance weight.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a geared motor employing an internally meshing planetary gear structure having a reduced axial length.

[0020]

According to the present invention, there is provided a first shaft, an eccentric member provided on the first shaft, and an eccentric member mounted on the first shaft so as to be rotatable eccentrically with respect to the first shaft via the eccentric member. An external gear, an internal gear in which the external gear is internally meshed, and a second shaft connected to the external gear via means for transmitting only the rotation component of the external gear. A balance weight for adjusting a load balance when the external gear swings in a geared motor employing an internal meshing planetary gear structure in which a reduction mechanism having an internal meshing planetary gear structure is combined with a motor. Is provided in an empty space in the motor to solve the above problem.

The load exerted on the bearing by the eccentric body and the balance weight and the deflection of the shaft will be described below with reference to the drawings.

FIG. 5A shows two bearings BR1 and BR2.
(Equivalent to bearings 27 and 28 in the examples of FIGS. 10 and 11) when only shaft A (motor shaft 24) and eccentric gear E (same eccentric body 4 and external gear 5) are installed. The state of the acting force is shown, and FIG. 5B shows the state of bending of the shaft A at that time. The centrifugal force fe acts on the eccentric gear E, and the resistance against this acts on the bearing BR1.
F1 acts on the bearing BR2 downward, and f2 'acts on the bearing BR2 upward. At this time, the axis A is bent so as to be convex downward as shown in FIG.

FIG. 6A shows only the balance weight BW in the portion of the shaft A between the two bearings BR1 and BR2.
FIG. 6B shows a state in which the shaft is bent at this time so that the phase is exactly 180 ° different from that of the eccentric body E of FIG. When the balance weight BW is at a position as shown in FIG. 6A, the centrifugal force fw acts downward on the balance weight BW. On the other hand, the drags f1 'and f2' act upward on the two bearings BR1 and BR2, respectively. At this time, as shown in FIG. 6B, the axis A is bent so as to be convex downward.

FIG. 7A shows only the balance weight BW in the portion of the shaft A between the two bearings BR1 and BR2.
FIG. 7B shows how the shaft A bends at this time. When the balance weight BW is at a position as shown in FIG. 7A, the centrifugal force fw ′ acts upward on the balance weight BW. 2
The drags f1 and f2 act downward on the two bearings BR1 and BR2, respectively. At this time, the axis A is bent so as to be convex upward as shown in FIG.

FIG. 8A shows the eccentric gear E of FIG.
FIG. 8B shows a state in which the balance weight BW shown in FIG. 6A is combined with the balance weight BW, and FIG. When the eccentric gear E and the balance weight BW are installed with a phase difference of 180 ° as shown in FIG. 8A, the drag f1 of FIG.
The load is not applied to the bearing BR1 just balanced with the drag f1 'of (a). On the other hand, the bearing BR2 has a drag f shown in FIG.
2 'and the resultant force f3 of the drag f2' in FIG. Also, the shaft A bends so as to protrude greatly downward as shown in FIG. At this time, as shown in FIG. 8A, no load is applied to the bearing BR1, but a large load is applied to the other bearing BR2.

FIG. 9A shows the eccentric gear E of FIG.
FIG. 9A shows a state where the balance weight BW shown in FIG. 7A is combined, and FIG. 9B shows a state where the shaft A is bent at this time. When the eccentric gear E and the balance weight BW have the same phase as shown in FIG.
5 and the reaction force f4 of the reaction force f1 shown in FIG. 7 (a) acts on the first bearing BR2.
The drag f2 'in FIG. 7A and the drag f2 in FIG. 7A cancel each other, and no load is applied. At this time, the deflection of the shaft A is obtained by combining the two deflections of FIG. 4B and FIG.
(B) As shown in 1, the shaft A does not bend and the shaft vibration is suppressed. At this time, as shown in FIG. 9A, a large load f4 is applied to the bearing BR1, while no load is applied to the bearing BR2.

As described above, the magnitude of the load applied to each of the bearings BR1 and BR2 and the manner in which the shaft A bends differ depending on how the balance weight BW is attached. Change the mounting method.

For example, in the case of FIG. 9A, the load on the bearing BR2 is small, so that the bearing BR2 can be made small and the whirling of the shaft A can be suppressed.

Therefore, it is considered that it is better to mount the balance weight as shown in FIG. 9A from the original purpose of suppressing the vibration of the shaft.

On the other hand, in the case of FIG. 8A, since the load applied to the bearing BR1 is small, the size of the bearing BR1 can be reduced. Therefore, when the rigidity of the shaft A is relatively large and vibration of the shaft does not need to be considered so much, and when it is desired to avoid an increase in the load on the bearing BR1, it is preferable to mount the bearing BR1 as shown in FIG. At this time, the load on the bearing BR2 increases, but when the load is originally applied, the increase in the load applied to the shaft A from the eccentric gear E is considered to be less affected because the bearing BR2 is smaller.

In mounting the balance weight BW, it goes without saying that not only the position but also the eccentricity and weight of the balance weight BW are taken into consideration.

According to the present invention, by mounting the balance weight BW in an empty space in the motor, that is, between the two bearings BR1 and BR2, it is possible to reduce the axial dimension by the balance weight BW as compared with the related art.

[0033]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a geared motor employing an internally meshing planetary gear structure according to a first embodiment of the present invention.

In the following description, the same or similar parts as those of the conventional example shown in FIG. 10 are assigned the same last two digits, and the repeated explanation is omitted.

An eccentric body 103 is fitted on the input shaft 101. An external gear 105 is attached to the eccentric body 103 via a bearing 104. The external gear 105 is in mesh with the internal gear 110 fixed to the casing 112.

The input shaft 101 is the motor shaft 1 of the motor 122
The rotation of the motor 122 is directly transmitted to the input shaft 101.

In the first embodiment, the balance weight 130 is located at a position close to the bearing 128 of the motor shaft 124 in an empty space in the motor 122.
And a 180 ° phase difference. That is, FIG.
The mounting method is as shown in FIG.

Hereinafter, the operation of the present embodiment will be described.

The rotation of the motor shaft 124 becomes the rotation of the input shaft 101 of the reduction mechanism 120 as it is, and the external gear 105
Swings with the rotation of the input shaft 101. As a result, the external gear 105 rotates slowly while vibrating due to the engagement between the external pin 111 corresponding to the internal teeth of the internal gear 110 and the external gear 105. The basic movement of the external gear is exactly the same as that of the conventional known example.

In the movement of the external gear 105, the swing component is absorbed by the gap between the inner roller hole 106 and the inner pin 107, and only the rotation component is transmitted through the inner pin 107 to the flange 114 of the output shaft 102. Is transmitted to

Eccentric rotation of eccentric body 103 and external gear 10
5 causes a load as shown in FIG. 5A to act on the shaft (the input shaft 101 and the motor shaft 124).
It bends and vibrates as shown in FIG. At this time, the load balance is adjusted by installing the balance weight 130. Then, as shown in FIG. 8A, the load applied to the bearing 127 can be almost eliminated. FIG.
In this embodiment, the bending and vibration of the shaft as shown in FIG. 2B are ignored because the shaft has a relatively large rigidity.

According to the present embodiment, the length of the input shaft 101 in the reduction mechanism 120 is shortened by the balance weight 130, and the axial dimension of the geared motor is shortened.

At this time, as described above, since the load applied to the bearing 127 is small, the size of the bearing 127 can be reduced, and the axial dimension can be further reduced.

On the other hand, when the bending of the shaft is to be suppressed without increasing the rigidity of the shaft, as shown in FIG. 9A, the balance weight 130 is set to be in the same phase as the eccentric body 103. It is good to install.

FIG. 2 shows the mounting position of the balance weight 130 on the motor shaft 124 as it is in FIG.
FIG. 3A shows the same phase as the eccentric body 103 as in FIG. In this case, as shown in FIG. 9B, it is possible to almost suppress the bending and vibration of the shaft (the input shaft 101 and the motor shaft 124). Further, although the load applied to the bearing 127 is large, the load is hardly applied to the bearing 128, so that the size of the bearing 128 can be reduced.

Next, a second embodiment of the present invention will be described.

FIG. 3 is a sectional view of a geared motor employing an internally meshing planetary gear structure according to a second embodiment of the present invention.

In the second embodiment, the balance weight 230 is provided inside the motor 222 by the motor shaft 224.
Of the bearing 227 side. In FIG. 3, the balance weight 230 is installed with a phase difference of 180 ° from the eccentric body 203, but may be mounted so as to have the same phase as the eccentric body 203.

In any case, the balance weight 230
Is installed in the motor 222, the speed reduction mechanism 220
The axial dimension of the input shaft 201 can be reduced.

The operation of this embodiment is the same as that of the above-described first embodiment, and the description is omitted.

Next, a third embodiment of the present invention will be described.

FIG. 4 is a sectional view of a geared motor employing an internal planetary gear structure according to a third embodiment of the present invention.

In the third embodiment, the bearing 226 is removed from the second embodiment. That is, as shown in FIG. 4, since the input shaft 301 is shortened by the width of the balance weight 330, the deflection of the input shaft is reduced, and the bearings 126 and 226 can be eliminated. This makes it possible to further reduce the axial dimension of the geared motor.

Although the embodiments described above all have a single external gear, it is apparent that the present invention may be applied to a case where there are two external gears (double rows). is there. By using two external gears, it is possible to increase the transmission capacity, maintain the strength, and maintain the rotational balance.
Strictly speaking, since a certain distance is inevitably present at the mounting position in the axial direction, the run-out is not always zero. In this case, the load balance can be further adjusted and the shaft vibration can be further suppressed by adding a balance weight. In addition, depending on the mounting position of the ballast weight, the load on each bearing can be reduced, and the size of the bearing can be reduced. This effect is particularly remarkable when the bearings 126 and 226 are omitted as shown in FIG.

[0056]

As described above, according to the present invention, the axial dimension of a geared motor can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a geared motor employing an internally meshing planetary gear structure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a geared motor adopting an internally meshing planetary gear structure showing a modification of the first embodiment.

FIG. 3 is a sectional view of a geared motor employing an internally meshing planetary gear structure according to a second embodiment of the present invention;

FIG. 4 is a sectional view of a geared motor employing an internally meshing planetary gear structure according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a force acting when only an eccentric body is attached to a shaft and a deflection of the shaft.

FIG. 6 is an explanatory diagram showing the force acting when only the balance weight is attached to the shaft and the deflection of the shaft.

FIG. 7 is an explanatory view showing a force acting when a balance weight alone is attached to a shaft and a deflection of the shaft.

FIG. 8 is an explanatory diagram showing the force applied when the eccentric body and the balance weight are attached to the shaft with a phase difference of 180 ° and the deflection of the shaft.

FIG. 9 is an explanatory diagram showing the force acting when the eccentric body and the balance weight are attached to the shaft in the same phase and the deflection of the shaft.

FIG. 10 is a cross-sectional view showing a geared motor employing a conventional internal meshing planetary gear structure.

11 is a sectional view taken along the line XI-XI in FIG.

[Explanation of symbols]

1, 101, 201, 301 ... input shaft 2, 102, 202, 302 ... output shaft 3, 103, 203, 303 ... eccentric body 5, 105, 205, 305 ... external gear 7, 107, 207, 307 ... Pins 10, 110, 210, 310 ... internal gears 12, 112, 212, 312 ... casings 14, 114, 214, 314 ... flanges 20, 120, 220, 320 ... reduction mechanism parts 22, 122, 222, 322 ... Motors 24, 124, 224, 324 ... motor shafts 4, 104, 204, 304, 26, 126, 226,
27, 127, 227, 327, 28, 128, 22
8, 328 ... Bearing

Claims (1)

[Claims] A first shaft; an eccentric body provided on the first shaft; an external gear mounted eccentrically rotatable with respect to the first shaft via the eccentric body; An internally meshing planetary gear structure having an internal gear in which the gear is internally meshed, and a second shaft connected to the external gear via means for transmitting only the rotation component of the external gear. In a geared motor employing an internally meshing planetary gear structure in which a speed reduction mechanism is combined with a motor, a balance weight for adjusting a load balance when the external gear swings is provided with an empty space in the motor. A geared motor employing an internally meshing planetary gear structure, wherein