JP3099156B2 - Planetary gear transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear type transmission.

[0002]

2. Description of the Related Art A conventional general planetary gear transmission is constructed as shown in FIG. FIG. 6 shows an example in which the speed reduction stage is one stage.

A metal sun gear 2 is press-fitted and fixed to one surface of a sun plate 1 made of a disk-shaped metal, and a plurality of, for example, at the same interval on the same circumference of the other surface, for example, 3
A planetary shaft 3 made of metal is press-fitted and fixed.

A planetary gear 4 having the same number of teeth is rotatably fitted to each of the planetary shafts 3, and each of the planetary gears 4 is located at the center of a lower lid 5 (in FIG. 6). An input gear 6 fixed to a drive shaft 6a of a motor or the like inserted from the hole 5a is meshed with an internal gear 8 on an inner peripheral surface of an internal gear case 7 made of a cylindrical metal. It revolves around the input gear 6 while rotating inside the internal gear 8, and constitutes one previous reduction stage.

[0005] An output shaft 10 is fixed to the center of one surface of a disk-shaped output plate 9 by a knurl 10a, and a plurality of output shafts are provided at equal intervals on the same circumference of the other surface. A planet shaft 11 made of three metals is press-fitted and fixed.

A planetary gear 12 having the same number of teeth is rotatably fitted to each of the planetary shafts 11, and each of the planetary gears 12 is meshed with a sun gear 2 fixed to the sun plate 1. The internal gear 8 meshes with the internal gear 8 of the internal gear case 7 and revolves around the sun gear 2 while rotating inside the internal gear 8 to constitute a final reduction gear. doing.

At upper and lower ends of the internal tooth case 7, lids 5 and 13 are fixed by screws 14 and 15, and an oil-impregnated bearing 16 is provided in a central hole 13a of the upper (in FIG. 6) lid 13. Are press-fitted and fixed.

The output shaft 10 is provided with a shaft hole 16 of an oil-impregnated bearing 16.
a, and the tip protrudes outward. Therefore,
The rotation of the drive shaft 6a such as a motor is transmitted from the input gear 6 as the rotation of the output shaft 10 that has been reduced through the previous reduction gear and the final reduction gear.

However, in the planetary gear type transmission, a large number of simultaneous meshes between the sun gear, the planetary gears, and the internal gears must be performed extremely precisely. And the accuracy of the mounting position of the planet shaft 3 and the output plate 9
Strict control is required for the mounting position accuracy and the like of the output shaft 10 and the planetary shaft 11 to the motor. For this reason, in the conventional planetary gear type transmission device, in order to strictly control the dimensions in metal processing at the time of manufacturing, the planetary gear type transmission device has to be expensive.

Further, a separate sun gear 2 and a planetary shaft 3 are fixed to the sun plate 1, and a separate output shaft 10 and the planetary shaft 11 are fixed to the output plate 9, so that the output plate 9 is continuously rotated by rotation. When a load is applied to the intermittent connection, there is a possibility that these fixed portions may loosen or slip.

In order to solve these problems, the present applicant has constructed the sun plate 1, the sun gear 2, and the planetary shaft 3 from a sintered metal integrally formed of a metal powder. A planetary gear type transmission device in which the shaft 10 and the planetary shaft 11 are also made of a sintered metal integrally formed of metal powder has been proposed (Japanese Patent Application No. 4-102609).

[0012]

However, in such a planetary gear type transmission device in which the output plate and the like are made of a sintered metal, (a) when the output plate is made of a sintered metal, If driven, seizure of the oil-impregnated bearing and the output shaft may occur, and rotation may stop.

(B) Further, when the internal gear case is also made of sintered metal, if the internal gear is driven continuously for a long time, the planetary gear meshing with the internal gear may wear and fall down, and the rotation may not be achieved. Sometimes it stopped.

The cause is considered as follows. As is well known, an oil-impregnated bearing is made of a sintered metal, has a large number of holes formed therein, and is impregnated with oil. When the rotation of the output shaft generates frictional heat due to friction with the oil-impregnated bearing, the oil in the pores of the oil-impregnated bearing expands due to the frictional heat, and flows out to the shaft hole, thereby serving as a lubricant between the output shaft and the shaft. Fulfill. The oil that has flowed out is infiltrated by capillary action from the end of the oil-impregnated bearing having many holes and returned into the oil-impregnated bearing. As described above, the oil in the oil-impregnated bearing flows out into the shaft hole due to frictional heat, and is circulated by the so-called pumping action of being returned to the oil-impregnated bearing again.

However, when the output plate located on the side of the oil-impregnated bearing is made of a sintered metal as described above, part of the oil flowing out of the oil-impregnated bearing is absorbed into the holes of the output plate, and the oil-impregnated bearing is thus absorbed. The amount of oil that is infiltrated is reduced. For this reason, it is considered that the oil in the oil-impregnated bearing is lost, and a seizure phenomenon occurs between the oil-impregnated bearing and the output shaft as described in (a) above.

Further, grease is applied to smooth engagement of the internal gear case and the planetary gears. If the internal gear case is made of a sintered metal as described above, this grease is applied to the internal gear case. The smoothness of the engagement is lost because the amount of grease is reduced by being absorbed into the holes. For this reason, it is considered that the planetary gear meshing with the internal gear as described in (b) wears and the teeth fall.

[0017]

Accordingly, the present invention is characterized in that at least one of the output plate and the internal tooth case is made of sintered metal sealed with an impregnating agent.

[0018]

Therefore, in the planetary gear type transmission of the present invention,
The holes in the output plate made of sintered metal are sealed, so that the oil flowing out of the oil-impregnated bearings is not absorbed into the output plate, and the internal teeth made of sintered metal Since the holes in the case are sealed, the grease between the internal gear case and the planetary gear will not be absorbed and absorbed in the internal gear case. Phenomena, and wear and fall of the planetary gear meshing with the internal gear,
No longer occurs, and long-term stable driving can be realized.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a planetary gear type transmission according to an embodiment of the present invention, and FIG. 2 is a sectional view of a main part of FIG.

As shown in FIG. 1 and FIG.
1, a sun gear 22 vertically projecting from the center of one surface of the sun plate 21, and three planetary shafts vertically projecting from equally spaced positions on the same circumference of the other surface. Reference numeral 23 denotes a sintered metal obtained by press-molding and sintering a metal (for example, pure iron) powder, impregnating with an impregnating agent (oil or resin), and performing a sealing treatment. At the time of integral molding, as shown in FIG. 1, a so-called rice ball-shaped blind hole 22a in which a part of an arc is evenly connected to the shaft of the sun gear 22 with a straight line.
Is formed, the vacuum state can be eliminated even though the mold is released from the mold at the time of molding, and the integrally molded product is easily removed.

As shown in FIG. 3, a ring-shaped concave groove 22b is formed at the base of the sun gear 22 during the integral molding.
Is formed, and the base is formed into an R shape 22c, so that the R shape is useful for preventing cracks when the mold is released from the mold, and the groove shape is a contact area between the sun plate 21 and its upper side (in FIG. 2) the planetary gear. And the resistance can be reduced, and the groove shape can secure a normal tooth profile up to the base of the sun gear 22.

Also, as shown in FIG.
When a ring-shaped stepped portion 24 is formed on the sun plate 21 so as to surround the bases of the three planetary shafts 23 and to connect the respective planetary shafts 23, the surface of the sun plate 21 on the planetary shaft 23 side is formed. It is possible to prevent the grease injected near the center portion from flowing out due to the centrifugal force at the time of rotation of the sun plate 21 by the steps of the step-shaped projections 24.

The integrally formed planetary shaft of the present embodiment is 3
As shown in FIG. 5, three other planetary shafts 23b are formed at every other radius at a position different in radius from the center of the sun plate 21 to form one integral molded product.
It is possible to obtain outputs of different specifications by providing a total of six planetary axes, one set of three, and selecting any one set of every other set. As shown in FIG. 5, if every other planetary shaft 23b having a different radius is formed with a concave portion 23c at the tip, every other type can be easily classified.

3 is formed integrally with the solar plate 21 having the above-described structure.
A planetary gear 25 having the same number of teeth is rotatably fitted to each of the planetary shafts 23 to form a front reduction gear A.

In the present embodiment, the pre-stage deceleration stage A is constituted by three stages as shown in FIG. 2 (one stage is omitted in FIG. 1), and the lowest stage (in FIGS. 1 and 2) Each of the planetary gears 25 in the reduction gear is provided with an input gear 29 fixed to a drive shaft 28 of a motor 27 inserted through a central hole 26a of the lid 26.
And meshes with the internal gear 31 on the inner peripheral surface of the cylindrical internal gear case 30, and revolves around the input gear 29 while rotating inside the internal gear 31.

Each of the planetary gears 25 in the upper pre-reduction stage is meshed with the sun gear 22 in the preceding stage and is also meshed with the internal gear 31. Revolves around 22.

Further, an output plate 32 having a disk-like shape and having a mounting hole 32a at the center, and an output plate 32 projecting vertically from the same circumferential position on the front deceleration stage A side of the output plate 32 on the same circumference. The planetary shaft 33 is a sintered metal in which pores are sealed by impregnating an impregnating agent (oil or resin) after pressing and sintering a metal (for example, pure iron) powder. Is molded.

Similarly to the case of the sun plate 21, when integrally formed, the output plate 32 has a thin ring shape so as to surround the roots of the three planetary shafts 33 and to connect between the planetary shafts 33. When the step-shaped protrusion 34 is formed, grease injected near the center of the surface on the side of the planetary shaft 33 flows out due to centrifugal force when the output plate 32 rotates. And lubricity can be maintained for a long period of time.

The sintered metal in which the output plate 32 and the planetary shaft 33 are integrally formed has a large number of holes, and these holes are sealed with an impregnating agent (eg, oil or resin). I have. That is, the pores are filled by impregnation with oil or resin.

An output shaft 35 is fixed to the center of the output plate 32 by a knurl 36. A planetary gear 37 having the same number of teeth is rotatably fitted to the planetary shaft 33 to form a final reduction stage B.

These planetary gears 37 are meshed with the sun gear 22 fixed to the uppermost sun plate 21 (in FIG. 2) of the preceding reduction stage A, and are engaged with the internal gear 31 of the internal gear case 30. The sun gear 22 revolves around the sun gear 22 while rotating within the internal gear 31.

The internal gear case 30 has a disk-shaped cover 30a having a hole 38 at the center, a cylindrical gear having an internal gear 31 formed on the inner peripheral surface and a plurality of screw holes 39 in the axial direction. The portion 30b is formed integrally with a sintered metal in which a metal (for example, pure iron) powder is pressed and sintered, the resin is impregnated, and the pores are sealed.

The internal tooth case 30 made of sintered metal is
Although it has a large number of holes, the holes are sealed with an impregnating agent (eg, oil or resin). That is, the pores are filled by impregnation with oil or resin. However, if oil is used as the impregnating agent, the exuded oil may flow into the motor 27 or into the built-in device, which may affect the motor performance or the built-in device. Is desirable.

An oil-impregnated bearing 40 is press-fitted and fixed in the hole 38 of the lid 30a of the internal gear case 30.
The output shaft 35 is rotatably housed in a central shaft hole 40a of the, and its tip protrudes outward.

A screw hole (not shown) at the lower end of the cylindrical portion of the internal tooth case 30 is provided with a cover 26 from below as shown in FIG.
The motor 27, which is in contact with the lower surface of the lid 26 from above in the two screw holes 39, is screwed with the screw 41b, as shown in FIGS.

The rotation of the input gear 29 at the end of the drive shaft 28 of the motor 27 is transmitted as the rotation of the output shaft 35, which has been reduced, through three stages of the previous reduction stage A and the final reduction stage B.

The oil in the oil-impregnated bearing 40 expands and flows out to the shaft hole 40a due to the frictional heat generated by the rotation of the output shaft 35, but the holes in the output plate 32 on the side of the oil-impregnated bearing 40 are impregnated with resin or oil. The oil is not absorbed by the output plate 32 because the oil is sealed. Therefore, the oil that has flowed out is absorbed and returned to the pores of the oil-impregnated bearing 40 by capillary action and circulates by pumping without loss. Disappears. Also, although the internal gear case 30 is in contact with the oil-impregnated bearing 40,
Since the holes of the internal tooth case 30 made of sintered metal are also sealed with resin, the oil is not absorbed into the internal tooth case 30,
No oil loss of the oil-impregnated bearing 40 occurs.

Further, the internal tooth case 30 made of sintered metal
Since the resin is impregnated and the pores are sealed, grease applied to smooth the engagement between the internal gear case 30 and the planetary gears 25 and 37 is absorbed and absorbed into the internal gear case 30. Therefore, smooth meshing is maintained even when driven for a long period of time, and the planetary gears 35 and 37 do not wear or fall.

In the above embodiment, both the output plate 32 and the internal tooth case 30 are made of sintered metal. However, one of the output plate 32 and the internal tooth case 30 is sealed. And the other may be made of a normal metal.

In the above embodiment, the output shaft 35 is fixed to the output plate 32, but the output shaft 35 is also fixed to the output plate 3.
2 and the planetary shaft 33 may be integrally formed.

[0041]

As described above, according to the present invention,
Since the output plate and / or the internal tooth case are made of sealed sintered metal, oil flowing out of the oil-impregnated bearing is not absorbed into the output plate and the internal tooth case The grease between the planetary gears is not absorbed and absorbed in the output shaft.
The tooth collapse phenomenon does not occur, and long-term stable driving can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a planetary gear type transmission according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of FIG.

FIG. 3 is a sectional view of a main part of the sun gear of FIG. 1;

FIG. 4 is a perspective view showing an embodiment of a solar plate.

FIG. 5 is a perspective view showing another embodiment of the solar plate.

FIG. 6 is a sectional view showing a configuration of a conventional general planetary gear type transmission.

[Explanation of symbols]

 Reference Signs List 21 sun plate 22 sun gear 23 planetary shaft 25 planetary gear 26 lid 27 motor 29 input gear 30 internal gear case 31 internal gear 32 output plate 33 planetary shaft 35 output shaft 37 planetary gear 40 oil-impregnated bearing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-29645 (JP, A) JP-A-2-292550 (JP, A) JP-A-61-211560 (JP, A) 127834 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 1/28-1/48

Claims (3)

(57) [Claims] 1. A bearing having a shaft hole, an internal gear case having an internal gear formed on an inner peripheral surface thereof, and a sun gear provided at a center of a surface of the sun plate on the bearing side.
A plurality of planetary axes are disposed on the other surface of the solar plate,
A planetary gear is rotatably fitted to each of the plurality of planetary shafts.
At least one or more preceding reduction stages, and an output shaft disposed at the center of the bearing-side surface of the output plate;
A plurality of planet shafts are provided on the other surface of the output plate,
Planet gears are rotatably fitted to several planet shafts respectively.
A final reduction gear stage, wherein the output shaft is rotatably fitted in a shaft hole of the bearing,
The planetary gears in the final reduction gear are the sun gears in the previous reduction gear.
In the engaged state, the final reduction gear and the previous reduction gear
Are incorporated in the internal tooth case, and the final deceleration stage
The planetary gears of the front and reduction stages are the internal gears of the internal gear case.
Planetary gear transmission that revolves while rotating and meshing with
In the guiding device,While comprising the bearing with an oil-impregnated bearing, The output plate adjacent to the bearing Sealed with impregnating agent
Composed of sintered metalThe friction caused by the rotation of the output shaft.
Oil that flows out of the bearing due to frictional heat should not be absorbed by the output plate.
Make sureA planetary gear type transmission. (2)A bearing having a shaft hole; An internal gear case in which an internal gear is formed on the internal peripheral surface, A sun gear is provided at the center of the bearing-side surface of the sun plate.
A plurality of planetary axes are disposed on the other surface of the solar plate,
A planetary gear is rotatably fitted to each of the plurality of planetary shafts.
At least one or more preceding reduction stages, An output shaft is disposed at the center of the bearing-side surface of the output plate,
A plurality of planet shafts are provided on the other surface of the output plate,
Planet gears are rotatably fitted to several planet shafts respectively.
With the final deceleration stage, The output shaft is rotatably fitted in a shaft hole of the bearing, and
Planetary teeth of the final reduction gear The car becomes the sun gear of the previous reduction stage
In the engaged state, the final reduction gear and the previous reduction gear
Are incorporated in the internal tooth case, and the final deceleration stage
The planetary gears of the front and reduction stages are the internal gears of the internal gear case.
Planetary gear transmission that revolves while rotating and meshing with
In the guiding device, While comprising the bearing with an oil-impregnated bearing, Sealing the internal tooth case holding the bearing with an impregnating agent
Made of sintered metal that is used to rotate the output shaft.
Oil flowing out of the bearing due to frictional heat
Planetary gear transmission characterized in that it is not absorbed by
Guiding device. (3)A bearing having a shaft hole; An internal gear case in which an internal gear is formed on the internal peripheral surface, A sun gear is provided at the center of the bearing-side surface of the sun plate.
A plurality of planetary axes are disposed on the other surface of the solar plate,
A planetary gear is rotatably fitted to each of the plurality of planetary shafts.
At least one or more preceding reduction stages, An output shaft is disposed at the center of the bearing-side surface of the output plate,
A plurality of planet shafts are provided on the other surface of the output plate,
Planet gears are rotatably fitted to several planet shafts respectively.
With the final deceleration stage, The output shaft is rotatably fitted in a shaft hole of the bearing, and
The planetary gears in the final reduction gear are the sun gears in the previous reduction gear.
In the engaged state, the final reduction gear and the previous reduction gear
Are incorporated in the internal tooth case, and the final deceleration stage
The planetary gears of the front and reduction stages are the internal gears of the internal gear case.
Planetary gear transmission that revolves while rotating and meshing with
In the guiding device, The inner tooth case is made of a sintered metal sealed with an impregnating agent.
Is applied between the internal gear case and the planetary gears.
Grease so that it does not absorb
A planetary gear type transmission.