JPH11210843A - Epicycle reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eccentric differential type epicycle reduction gear in which internal gear pins can be replaced in a state where an outer ring part of a bearing is fixed to a case, and which is excellent in workability and is highly efficient. SOLUTION: In an eccentric differential type epicycle reduction gear which is provided with an internal gear consisting of a pin 12a provided on the inner periphery of a case 11, external gears 14, 15, a crankshaft for revolving the gears 14, 15 with a specified eccentricity, a carrier rotatably connected to the case 11 through rolling bearings 20A, 20B, and which inputs rotation to the crankshaft or the external gears 14, 15 and takes out reduction output from the internal gear or the carrier, each of the rolling bearings 20A, 20B is provided with an outer ring part 21 forming a bearing-rolling contact surface 21a on the case 11 side, and an inner ring part 22 forming a bearing-rolling contact surface 22a on the carrier side and regulating the axial movement of the plural pins 12a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric differential type planetary gear reducer, and more particularly to a planetary gear reducer having a plurality of pins on an inner periphery of a case.

[0002]

2. Description of the Related Art Conventionally, eccentric differential gears are used for various machines that require large torque and impact resistance in output rotation, as typified by traveling drives for industrial vehicles, turning drives for industrial robots, and winches. A planetary gear reducer of the type is frequently used. As this type of planetary gear reducer, for example,
As described in JP-A-9-36661, an external gear meshing with an internal gear having an internal gear having a plurality of internal teeth on the inner periphery and having an epitrochoid tooth shape having fewer teeth than the internal teeth on the outer periphery. Some include a tooth gear, a plurality of cranks that support the external gear so as to be able to revolve with a predetermined eccentric amount with respect to the center axis of the internal gear, and a carrier connected to the cranks.

The internal gear of this speed reducer has a predetermined number of circular grooves formed at equal pitches on the inner periphery of an annular case, and a cylindrical pin is rotatably mounted in each of the circular grooves to form a circular tooth. Internal teeth are used to prevent a decrease in efficiency due to friction between the internal teeth and the external gear.

[0004]

However, in the above-mentioned conventional eccentric differential type planetary gear reducer, the rolling members interposed between the carrier and the case are provided at both ends of a large number of pins forming internal teeth. Since the outer ring of the bearing was opposed, the displacement of these pins in the axial direction was restricted.
There were the following problems.

At the time of assembling the speed reducer, for example,
A case and an external gear disposed inside the case such that one pin is located between two adjacent external teeth and another pin is located at an opposite position (a position 180 degrees apart). After inserting all the pins that form the internal teeth by rotating the case at the pitch angle of the internal teeth, insert the two pins between them, and then insert the outer ring of the rolling bearing into the case. Fit into and fix.

In such a case, when the outer ring of the rolling bearing is fixed to the case, the pin is prevented from coming off, but a defect is found by inspection or the like, and the assembled speed reducer is disassembled or the pin is replaced. When the work becomes necessary, the replacement work cannot be performed unless the outer ring of the rolling bearing is removed from the case. Also, for example, measuring the efficiency of the speed reducer and selecting the pin with the optimal diameter by actual matching requires the work of repeating the above-mentioned outer ring removal work,
It cannot be implemented, and it is not easy to obtain a highly efficient reduction gear.

Accordingly, the present invention provides a highly efficient eccentric differential planetary gear reducer which is excellent in workability by enabling pin replacement work while fixing the outer ring portion of the rolling bearing to the case. The purpose is to:

[0008]

In order to achieve the above object, an invention according to claim 1 is an internal gear including a plurality of pins provided on an inner periphery of a case, and the internal gear in the case. An external gear that meshes with the crankshaft that rotatably supports the external gear with a predetermined eccentric amount with respect to the center axis of the internal gear; and a rotatably coupled to the case via a rolling bearing. And a carrier that rotatably supports the crankshaft, respectively, and inputs rotation from the outside to the crankshaft or the external gear to revolve the external gear and reduce the speed from the internal gear or the carrier. In an eccentric differential planetary gear reducer configured to take output, the rolling bearing forms an outer ring portion that forms a bearing rolling surface on the case side, and forms a bearing rolling surface on the carrier side. Duplicate An inner ring portion for restricting the axial movement of the pins is characterized in that it has a.

Therefore, when the inner ring of the rolling bearing is assembled together with the carrier, the pin is prevented from coming off. However, when a defect is found by inspection or the like and the assembled reducer is disassembled, the rolling bearing is disassembled. When the inner ring is removed together with the carrier, the pins can be removed and re-mounted without removing the outer ring of the rolling bearing from the case.

Further, when the inner ring part also regulates the movement of the external gear in the axial direction of the pin, the number of parts can be further reduced. Further, when the outer ring portion is formed integrally with the case or the inner ring portion is formed integrally with the carrier, the bearing is a large-sized component having a relatively large diameter. As the number of parts is small, the cost of parts and the number of assembly steps can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3
FIG. 1 is a view showing a first embodiment of an eccentric differential planetary gear reducer according to the present invention. As shown in FIGS. 1 and 2, the planetary gear reducer 1 includes an annular case 11 having a plurality of pin mounting grooves
And an internal gear 12 comprising a plurality of pins 12a (internal teeth) provided on an inner peripheral portion of the internal gear 1.
External teeth 1 having a different number of teeth at a predetermined pitch corresponding to 2
External gears 14 and 15 having 4a and 15a and meshing with the internal gear 12 in the case 11, and these external gears 14 and 15
(E.g., three) of the crankshafts 1 that support revolving motion with a predetermined eccentricity e with respect to the center axis of the internal gear 12 via bearings 16a and 16b while maintaining a rotation interval of 180 degrees with respect to the center axis.
8 and a carrier 19 rotatably connected to the case 11 via rolling bearings 20A and 20B and rotatably supporting both ends of the crankshaft 18.

Further, the crankshaft 18 is mounted on each of the bearings 1.
While being rotatably supported by the carrier 19 via 7a and 17b, rotation from an external drive gear shaft (not shown) is input via an input gear 31 mounted on at least one of the shaft ends thereof, The external gears 14 and 15 are revolved. The external gears 14 and 15 are
When all the teeth are engaged, the number is smaller than the number of internal teeth (for example, 1
Or only 2), but as shown in FIG. 2, when some external teeth are meshed at a predetermined interval in the circumferential direction, the number of teeth is larger than that of the internal teeth. When the external gears 14 and 15 revolve while meshing with the external gears 14, a predetermined angle corresponding to the difference in the number of teeth is used for each revolution.
15 rotates, whereby a deceleration output corresponding to the rotation can be taken out from the internal gear 12 or the carrier 19.

Since such a speed reduction mechanism itself is known, it will not be described in further detail, but the external gear 1 uses a center crank that rotates on the center axis of the internal gear 12.
Alternatively, the rotation input may be directly input to the center portion of the fourth and the fifth. As shown in FIG. 3, the rolling bearing 20 </ b> A has an outer ring portion 21 that forms a bearing rolling surface 21 a on the case 11 side.
And an inner ring portion 22 which forms a bearing rolling surface 22a on the carrier 19 side and regulates the movement of the plurality of pins 12 to one side in the axial direction on the inner side surface, and rolling between the outer ring portion 21 and the inner ring portion 22 It has a plurality of ball-shaped (or roller-shaped) rolling elements 23 provided so as to be capable of being provided, and a retainer 24 for holding the rolling elements 23 at predetermined intervals in the circumferential direction. The inner ring portion 22 also restricts movement of the external gears 14 and 15 in the axial direction of the pin 12a. In addition, the rolling bearing 20B is configured in exactly the same manner as the rolling bearing 20A, and these rolling bearings 20A, 20B
Are fitted in the stepped holes 11a and 11b of the case 11 so that they are opposite to each other on both sides in the axial direction of the internal gear 12.

A plurality of carriers 19 (for example, three carriers) are provided.
The first and second plates 41 and 42 are integrally connected by bolts 32. The rolling bearings 20 are provided on stepped portions 41a and 42a provided on the outer peripheral portions thereof.
The inner ring portions 22 of A and 20B are fitted respectively. 41b and 42b are the first and second plates 4
1, 42 are central through-holes formed respectively in
Reference numerals 14b and 15b denote through holes at the center formed in the external tooth assist wheels 14 and 15. Reference numeral 42c denotes a column provided on the second plate 42 so as to contact the first plate 41.
The bolt 32 penetrates the inside.

In the speed reducer of the present embodiment configured as described above, when the inner races 22 of the rolling bearings 20A and 20B are assembled to the case 11 together with the carrier 19, the pin 12a is prevented from coming off by the inner race 22. Is done. Therefore, there is no need to separately provide a retaining member. Further, since the inner ring portion 22 also restricts the movement of the external gears 14 and 15 in the axial direction of the pin 12a, the number of parts is further reduced.

On the other hand, when a defect is found by inspection or the like and the assembled speed reducer is disassembled, the bolt 32 is loosened, and the inner ring portion 22 of the rolling bearing 20A and the case 11 and the first plate 41 of the carrier 19 are removed. Second plate 4
Removed from one side. Therefore, the pin 12a can be removed and re-attached without removing the outer ring portion 21 from the case 11. Therefore, the pin 12a can be replaced while the outer ring portion 21 of the rolling bearings 20A and 20B is fixed to the case 11. For example, the efficiency of the reduction gear 1 is measured and the pin
2a can be selected. As a result, it is possible to provide a simple and highly efficient eccentric differential planetary gear reducer excellent in workability during assembly and maintenance. Further, in the present embodiment, the pitch of the internal teeth 12 is expanded to a plurality of teeth (for example, two teeth) of the external teeth 14a and 15a, so that the work of mounting and replacing the pins 12a is greatly reduced. Can be.

Since the inner ring portion 22 of the rolling bearing 20A and the pin 12a of the internal gear 12 rotate relative to each other, the shaft end portion of the adjacent pin 12a and the inner ring portion 22 can be brought into sliding contact with some clearance. However, the pin 12a usually has no problem because it has abrasion resistance and high rigidity that can withstand heavy load meshing with the external gears 14 and 15. In addition, the relative rotation between the internal gear 12 and the inner ring portion 22, which is the deceleration output of the high reduction ratio, becomes low speed.
Since the load in the axial direction does not substantially act on the shaft a, the sliding contact between the shaft end of the pin 12a and the inner ring portion 22 does not pose a problem, and a lubricating agent such as grease or a member corresponding thereto is formed on the gear meshing portion. This is even more so when providing.

FIG. 4 is a view showing a second embodiment of the eccentric differential type planetary gear reducer according to the present invention. Note that in the embodiment described below, members having the same configuration as the above-described example or a configuration equivalent thereto are denoted by the same reference numerals as those in FIGS. As shown in FIG. 4, in the speed reducer 2 of this embodiment, the rolling bearing 5
The outer ring portion 51 of 0A and 50B has a bearing rolling surface portion 51a integrated with the case 11, and the bearings 50A and 50B, which are relatively large-diameter large components, are reduced in the number of components, and the component cost and assembly are reduced. The man-hour can be reduced. Further, the inner ring portion 52 mounted on the second plate 42 also regulates the movement of the external gears 14 and 15 in the axial direction of the pin 12a, thereby reducing the number of components.

In the present embodiment, the same effects as those of the above-described embodiment can be obtained.
The number of parts A and 50B can be reduced, and the manufacturing cost can be reduced. FIG. 5 is a view showing a third embodiment of the eccentric differential planetary gear reducer according to the present invention.

As shown in FIG. 5, in the speed reducer 3 of this embodiment, the inner ring portion 62 of the rolling bearings 60A and 60B has a bearing rolling surface portion 62a integral with the carrier 19, and has a relatively large diameter. The bearings 60A and 60B, which are large-sized parts, have a small number of parts, thereby reducing parts costs and man-hours for assembly. Further, the inner ring portion 62 integrated with the carrier 19 also regulates the movement of the external gears 14 and 15 in the axial direction of the pin 12a, thereby reducing the number of parts.

In this embodiment, the same effects as those of the above-described embodiment can be obtained.
The number of parts A and 60B can be reduced, and the manufacturing cost can be reduced.

[0022]

According to the first aspect of the present invention, the pin can be removed and re-mounted without removing the outer ring of the rolling bearing from the case, so that a highly efficient eccentric differential planetary with excellent workability. A gear reducer can be provided. Further, according to the second aspect of the present invention, since the inner ring portion of the rolling bearing regulates the movement of the external gear in the axial direction of the pin, the number of parts can be further reduced.

Further, as described in claim 3 or 4,
If the outer ring is formed integrally with the case or the inner ring is formed integrally with the carrier, the bearings, which are relatively large-diameter large parts, are reduced in the number of parts, thereby reducing parts costs and assembly man-hours. Can be planned.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of an eccentric differential planetary gear reducer according to the present invention.
FIG. 2 is a side sectional view showing the embodiment.

FIG. 2 is a front sectional view of the speed reducer of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part of the speed reducer shown in FIG.

FIG. 4 shows a second embodiment of the eccentric differential planetary gear reducer according to the present invention.
FIG. 2 is a side sectional view showing the embodiment.

FIG. 5 shows a third embodiment of the eccentric differential planetary gear reducer according to the present invention.
FIG. 2 is a side sectional view showing the embodiment.

[Explanation of symbols]

1, 2, 3 Eccentric differential planetary gear reducer 11 Case 12 Internal gear 12a Pin (internal gear) 14, 15 External gear 14a, 15a External gear 18 Crankshaft 19 Carrier 20A, 20B; 50A, 50B; 60A, 60B
Rolling bearing 21a Bearing rolling surface 21 Outer ring portion 22a Bearing rolling surface 22 Inner ring portion 23 Rolling element 24 Retainer 41 First plate 42 Second plate 41a, 42a Stepped portion 51 Outer ring portion 51a Bearing rolling surface portion 52, 62 Inner ring portion 62a bearing rolling surface

Claims (4)

[Claims] 1. An internal gear comprising a plurality of pins provided on an inner periphery of a case, an external gear meshed with the internal gear in the case, and a center of the external gear in the case of the internal gear. A crankshaft that supports a revolving motion with a predetermined eccentric amount with respect to an axis, and a carrier that is rotatably coupled to the case via a rolling bearing and that rotatably supports the crankshaft, respectively, An eccentric differential planetary gear reducer configured to revolve the external gear by inputting an external rotation to the crankshaft or the external gear to take out the reduction output from the internal gear or the carrier, wherein the rolling The bearing has an outer ring portion that forms a bearing rolling surface on the case side, and an inner ring portion that forms a bearing rolling surface on the carrier side and regulates axial movement of the plurality of pins. When Planetary gear reducer. 2. The planetary gear reducer according to claim 1, wherein said inner ring portion regulates movement of said external gear in the axial direction of said pin. 3. The planetary gear reducer according to claim 1, wherein the outer ring portion is formed integrally with the case. 4. The planetary gear reducer according to claim 1, wherein the inner ring portion is formed integrally with the carrier.