JPH08312742A - Planetary roller type power transmission device - Google Patents

Abstract

PURPOSE: To prevent lowering of transmission torque due to a bolt hole in which a fixed wheel is fixed. CONSTITUTION: A plurality of planetary rollers 40 rotatably supported at the carrier part of a second shaft arranged coaxially internally of a fixed wheel 21 so as to be rotatable independently from a first shaft 28 are disposed in a pressure contact state between the fixed wheel 21 fixed to a housing and a first shaft 28 coaxially and rotatably inserted internally of the fixed wheel 21. The fixed wheel 21 is fixed to a housing by axially inserting the number of bolts 23 different from the number of planetary rollers 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary roller type power transmission device used in, for example, a reduction motor, and more specifically, to a fixed ring fixed to a housing and coaxially rotatable inside the fixed ring. Is rotatably supported by a carrier part of a second shaft coaxially arranged inside the fixed ring so as to rotate independently of the first shaft between the first shaft and the first shaft. The present invention relates to a planetary roller type power transmission device in which a plurality of planetary rollers are arranged in a pressure contact state.

[0002]

2. Description of the Related Art In a power transmission device of this type, a plurality of planet rollers are arranged at equal intervals in the circumferential direction between a fixed wheel and a first shaft. Further, the planetary roller is disposed in a pressure contact state between the fixed ring and the first shaft, and rolls on the inner peripheral surface of the fixed ring and the outer peripheral surface of the first shaft to be fixed to the planetary roller. A predetermined torque is transmitted between the first shaft and the second shaft by the pressure contact force between the wheel and the first shaft. The fixed ring may be fixed to the housing with a plurality of bolts that pass through it in the axial direction.In that case, in the conventional case, the same number of bolts as the number of planet rollers are arranged at equal intervals in the circumferential direction. Has been done. When the fixed ring is fixed with the bolts that pass through the fixed ring, the radial thickness of the fixed ring becomes thin in the portion where the bolt hole is formed. Therefore, when the planetary roller moves in the circumferential direction to the bolt hole portion of the fixed wheel, the thin bolt hole portion of the fixed wheel bends,
The pressure contact force with the planetary roller is reduced, and the transmission torque by the planetary roller is reduced. In the conventional power transmission device, since the number of bolts for fixing the planetary roller and the fixed ring is the same as described above, when one planetary roller moves to the bolt hole portion of the fixed ring, the remaining All the planetary rollers are also located in the other bolt hole portions, and the transmission torque is simultaneously reduced in all the planetary roller portions, and as a result, the transmission torque of the entire power transmission device is significantly reduced.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a planetary roller power transmission device capable of preventing a reduction in transmission torque due to a bolt hole for fixing a fixed wheel.

[0004]

Means for Solving the Problems and Effects of the Invention A planetary roller type power transmission device according to the present invention comprises a fixed ring fixed to a housing, and a fixed ring coaxially and rotatably inserted inside the fixed ring. A plurality of rotatably supported by a carrier portion of a second shaft coaxially arranged inside the fixed ring so as to rotate independently of the first shaft. In a planetary roller type power transmission device in which planetary rollers are arranged in pressure contact, the fixed wheel is fixed to the housing by axially inserting a different number of bolts from the number of planetary rollers. It is characterized by that.

Since the number of bolts for fixing the fixed ring is different from the number of planetary rollers, when one planetary roller moves to the bolt hole portion of the fixed ring, the remaining planetary rollers are all in the bolt hole. Not located in any part,
The transmission torque does not decrease at all the planetary roller parts at the same time. Therefore, the reduction in the transmission torque of the entire power transmission device due to the bolt holes is smaller than that of the conventional one.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a reduction motor will be described below with reference to the drawings. In the following description, the left and right in FIG. 1 are left and right.

The reduction motor shown in the drawings has a stator (12), a rotor (13), a rotor (13) inside a flat cup-shaped stator frame (10) having an open left end and a bracket (11) closing the open end.
It is a flat type with a reduction gear mechanism (14) and an output shaft (15) built-in. The frame (10) and the bracket (11) form a housing of the electric motor.

The output shaft (15) includes a frame (10) and a bracket.
It passes through the center of (11) to the left and right and is rotatably supported by bearings (16) and (17). Although illustration is omitted, a detector such as a rotary encoder is connected to the right end portion of the output shaft (15), and a driven shaft is connected to the left end portion. Stator (1
2) is fixedly provided on the inner circumference of the frame (10) so as to be concentric with the output shaft (15).

The rotor (13) has a cylindrical shape, and the stator (12)
Are arranged concentrically inside. A two-stage planetary roller reduction mechanism (14) is provided mainly in the space between the stator (12) and the output shaft (15), as described below. That is, the first fixed ring (19), the spacer (20), and the second fixed ring are sequentially arranged between the four ring-shaped partition plates (18) from the right.
(21) are each sandwiched and a spacer (22) is further stacked on the left side of the leftmost partition plate (18) to form a cylindrical shape, which is arranged in a circular center just inside the rotor (13), The bracket (12) and a plurality of bolts (23) and nuts (24) that pass through these and the bolt holes of the bracket (11)
It is fixed at (11). The partition plate (18) has an inner diameter smaller than the inner diameters of the fixed rings (19) and (21), and protrudes inward from both ends of the fixed rings (19) and (21) to the inner circumference of the fixed rings (19) and (21). Ring Groove (25) (2
6) is formed. A hollow input shaft (27) is rotatably fitted to the right outer circumference of the output shaft (15) in the frame (10), and a hollow intermediate shaft (28) is rotatably fitted to the left outer circumference thereof. The inner circumference of a perforated disc-shaped end plate (29) is fixed to the right end of the input shaft (27), and the right end of the rotor (13) is fixed to the outer circumference of this end plate (29). . An annular groove (30) is formed on the left outer peripheral surface of the input shaft (27), and the bottom surface thereof serves as the first sun roller portion (31).
An outward flange-shaped first carrier portion (32) is formed at the right end of the intermediate shaft (28). An annular groove (33) is formed on the left outer peripheral surface of the intermediate shaft (28), and the bottom surface thereof serves as the second sun roller portion (34). Also, the output shaft in the frame (10)
At the left end of (15), there is an outward flange-shaped second carrier part.
(35) is formed. First carrier part of the intermediate shaft (28)
The (32) has a plurality of pins (36), which are parallel to the output shaft (15) and project around the right input shaft (27) (for example, five).
It is fixed on the same circumference centered around 5) at equal intervals, and the first planetary roller (37) is rotatably attached to each pin (36) via a needle roller bearing (38). Installed. These planet rollers (37) are fitted in the groove (30) of the input shaft (27) and the groove (25) of the first fixed ring (19), and are connected to the first sun roller section (31) and the first sun roller portion (31). It makes pressure contact with the fixed wheel (19) and rolls between them. In the second carrier part (35) of the output shaft (15), the output shaft (15)
Pins (39) parallel to (15) and protruding around the right intermediate shaft (28) are fixed at equal intervals on the same circumference centered on the output shaft (15). Each pin (3
A second planetary roller (40) is rotatably attached to the shaft 9) via a needle roller bearing (41). These planet rollers (4
(0) fits in the groove (33) of the intermediate shaft (28) and the groove (26) of the second fixed ring (21), and the second sun roller portion (34) and the second fixed ring (21). ) And rolls between them.

The first stage and the second stage of the reduction mechanism (14) respectively constitute a planetary roller type power transmission device, and in the first stage power transmission device, the input shaft (27) is the first shaft. , The intermediate shaft (28) constitutes the second shaft, and in the second stage power transmission device, the intermediate shaft (28) constitutes the first shaft and the output shaft (15) constitutes the second shaft. There is.

In the above reduction motor, the rotation of the rotor (13) is directly transmitted to the input shaft (27) via the end plate (29). Then, the rotation of the input shaft (27) is caused by the rotation of the first sun roller unit.
(31), the first fixed ring (19) and the first planetary roller (37) reduce the speed and transmit the intermediate shaft (28) to the intermediate shaft (2).
The rotation of 8) is performed by the second sun roller part (34) and the second fixed ring (21).
And the second planetary roller (40) reduces the speed by the same amount and transmits it to the output shaft (15).

At each stage of the speed reducing mechanism (14), a bolt (2) for fixing the fixed wheels (19) (21) to the bracket (11) is provided.
While the number of 3) is 6, the number of planetary rollers (37) (40) is 5, and the numbers of both are different, so the bolt (23)
It is possible to prevent the reduction of the transmission torque due to the bolt holes of the fixed wheels (19) and (21) through which is inserted. Next, the reason for the second stage of the speed reduction mechanism (14) will be described with reference to FIG. When a bolt hole is formed in the fixed ring (21), the thickness of the fixed ring (21) in the radial direction becomes thin at the bolt hole portion, and the fixed ring (21) easily bends in the radial direction accordingly. . FIG. 2 shows a state in which one planetary roller (40) has moved to the uppermost bolt hole portion of the fixed ring (21) in the circumferential direction, as can be seen from this figure. , The number of bolt holes is different from that of the planetary roller (40), so when one planetary roller (40) moves to the part of the bolt hole, the remaining four planetary rollers (40) are all bolt holes. It is located at a position deviated from the circumferential direction. Therefore, at the bolt hole part where the planetary roller (40) has moved, the fixed wheel is pressed by the pressure contact force with the planetary roller (40).
(21) bends outward in the radial direction, and the pressure contact force with this planetary roller (40) becomes small, and the transmission torque by this planetary roller (40) decreases, but the remaining four planetary rollers (40) In the portion, the fixed ring (21) is not easily bent, and the transmission torque does not decrease. Therefore, the reduction of the transmission torque of the entire power transmission device is extremely small as compared with the conventional one.

In the case of the above embodiment, the rotation of the rotor (13) is reduced by the two-stage planetary roller reduction mechanism (14) and the output shaft
Since it is transmitted to (15), a large reduction ratio can be obtained as a whole. The planetary roller speed reduction mechanism (14) itself can be miniaturized, and most of the planetary roller speed reduction mechanism (14) is disposed inside the cylindrical rotor (13), so that the reduction motor as a whole can be miniaturized. The length reduction due to the speed reduction mechanism is very small.
Moreover, since the output shaft (15) also serves as the rotor shaft of the conventional reduction motor, the weight is reduced accordingly.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a reduction motor showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

[Explanation of symbols]

 (10) Stator frame (11) Bracket (12) Stator (13) Rotor (14) Planetary roller reduction mechanism (15) Output shaft (19) (21) Fixed ring (23) Bolt (27) Input shaft (28) Intermediate Axis (32) (35) Carrier part (37) (40) Planetary roller

Claims (1)

[Claims] 1. Between a fixed ring fixed to a housing and a first shaft which is coaxially and rotatably inserted inside the fixed ring and which rotates independently of the first shaft. In a planetary roller type power transmission device in which a plurality of planetary rollers rotatably supported by a carrier portion of a second shaft coaxially arranged inside the fixed ring are arranged in pressure contact with each other, The planetary roller type power transmission device, wherein the fixed wheel is fixed to the housing by axially inserting bolts different in number from the planetary rollers.