JPH06337043A - Epicyclic gear type transmission device - Google Patents

Abstract

PURPOSE:To prevent a seizure between a bearing and an output shaft or abrasion and tooth fall in an epicyclic gear, which gears with an internal tooth gear on the inner circumferential face of an internal tooth case, in an epicyclic gear type transmission device using sintered metal for an output plate or the like. CONSTITUTION:As one/both of an output plate 32 and an internal tooth case 30 is/are composed of sintered metal, which is realing treated by an impregnant, the oil flows out from a bearing is not absorbed in the output plate 32. As the holes of the internal tooth case 30 composed of sintered metal are sealed, grease between the internal tooth case 30 and an epicyclic gear 37 is not absorbed in the internal tooth case 30, so that a seizure between the bearing and an output shaft 35 or abrasion and tooth fall in the epicyclic gear 37 gearing with an internal tooth gear 31 do not occur even when a device is driven for a long time, and consequently, stable driving for a long time can be achieved.

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 device.

[0002]

2. Description of the Related Art A conventional general planetary gear type transmission device is constructed as shown in FIG. FIG. 6 shows an example in which the number of deceleration stages is one.

A metal sun gear 2 is press-fitted and fixed to one surface of a solar plate 1 made of a disk-shaped metal, and a plurality of metal sun gears 2 are equally spaced on the same circumference of the other surface, for example, Three
The 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 planetary gear 4 is located at the center of the lid 5 on the lower side (in FIG. 6). It meshes with an input gear 6 fixed to a drive shaft 6a such as a motor inserted through the hole 5a, and with an internal gear 8 on the inner peripheral surface of an internal gear case 7 made of a cylindrical metal, It revolves around the input gear 6 while rotating in the internal gear 8 and constitutes one front reduction stage.

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

A planetary gear 12 having the same number of teeth is rotatably fitted on each planetary shaft 11, and each planetary gear 12 is meshed with a sun gear 2 fixed to the sun plate 1. Further, it is meshed with the internal gear 8 of the internal case 7 and revolves around the sun gear 2 while rotating within the internal gear 8 and constitutes a final reduction stage. is doing.

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

The output shaft 10 is a shaft hole 16 of an oil-impregnated bearing 16.
It is housed in a and has a tip protruding outward. Therefore,
The rotation of the drive shaft 6a such as a motor is transmitted from the input gear 6 through the preceding reduction stage and the final reduction stage as the reduced rotation of the output shaft 10.

In the planetary gear type transmission device, however, a large number of simultaneous meshes among the sun gears, the planetary gears, and the internal gears must be carried out very precisely, so that the sun gear 2 to the sun plate 1 is And planetary shaft 3 mounting position accuracy, output plate 9
Strict control of the mounting position accuracy of the output shaft 10 and the planetary shaft 11 is required. For this reason, in the above-described conventional planetary gear type transmission device, the dimensional control in metal processing during manufacturing is strict, so that the planetary gear type transmission device is inevitably expensive.

Further, since the sun gear 1 and the planetary shaft 3 are separately attached to the sun plate 1, and the output shaft 10 and the planetary shaft 11 are separately attached to the output plate 9, they are continuously rotated. If a load is applied to the intermittent connection, these fixed parts may become loose or slip.

Therefore, in order to solve these problems, the applicant of the present invention constructed the sun plate 1, the sun gear 2, and the planetary shaft 3 from a sintered metal integrally formed of metal powder, and also the output plate 9 and the output. A planetary gear type transmission device has been proposed in which the shaft 10 and the planet shaft 11 are made of sintered metal, which is also integrally formed of metal powder (Japanese Patent Application No. 10-1069).

[0012]

However, in the planetary gear type transmission device in which the output plate and the like are made of the sintered metal as described above, (a) when the output plate is made of the sintered metal, the output plate is continuously made for a long time. When driven, a seizure phenomenon between the oil-impregnated bearing and the output shaft may occur, and the rotation may stop.

(B) Further, when the inner tooth case is also made of sintered metal and continuously driven for a long time, the planet gears meshing with the inner tooth gear may be worn or collapsed, and rotation may occur. It was sometimes stopped.

The cause is considered as follows. As is well known, the oil-impregnated bearing is made of a sintered metal, has a large number of holes formed therein, and these holes are impregnated with oil. If frictional heat is generated due to friction with the oil-impregnated bearing due to rotation of the output shaft, this frictional heat causes the oil in the holes of the oil-impregnated bearing to expand and flows out into the shaft hole, where it functions as a lubricant between the output shaft. Fulfill. Then, the oil that has flowed out is absorbed and returned to the inside of the oil-impregnated bearing from the end portion of the oil-impregnated bearing having many holes by the capillary phenomenon. In this way, the oil in the oil-impregnated bearing is circulated by the so-called pumping action of flowing out to the shaft hole by frictional heat and returning to the oil-impregnated bearing again.

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

Further, although grease is applied in order to make the meshing between the inner tooth case and the planetary gear smooth, if the inner tooth case is made of sintered metal as described above, this grease will Since the amount of grease absorbed by the pores is reduced, the smoothness of meshing is lost. For this reason, it is considered that the phenomenon of wear and tooth collapse of the planetary gear that meshes with the internal gear as described in (b) above occurs.

[0017]

Therefore, the present invention is characterized in that both or one of the output plate and the inner tooth case is made of a sintered metal that is sealed with an impregnating agent.

[0018]

Therefore, in the planetary gear type transmission device of the present invention,
Since the holes in the output plate made of sintered metal are sealed, the oil flowing out from the oil-impregnated bearing will not be absorbed by the output plate, and the internal teeth made of sintered metal will not be absorbed. Since the holes of the case are sealed, the grease between the inner tooth case and the planetary gears will not be absorbed into the inner tooth case, so even if it is driven for a long time, the bearing and output shaft will not burn. Phenomenon, wear of the planetary gear that meshes with the internal gear and tooth collapse phenomenon,
It will not occur and stable driving for a long time 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 device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of essential parts of FIG.

As shown in FIGS. 1 and 2, a disk-shaped solar plate 2
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 is a sintered metal that is obtained by pressure-molding and sintering a metal (pure iron) powder, impregnating an impregnating agent (oil or resin) and sealing the metal, and is integrally molded. In the case 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 with a straight line to the shaft portion of the sun gear 22 is formed.
By forming, the vacuum state can be eliminated when the mold is released from the mold at the time of molding, and the integrally molded product is easily removed.

Further, as shown in FIG. 3, a ring-shaped recessed groove 22b is formed in the base of the sun gear 22 during this integral molding.
And the base is formed into an R shape 22c, the R shape helps prevent cracks when the mold is released from the mold, and the groove shape has a contact area between the sun plate 21 and the planet gear above the sun plate 21 (in FIG. 2). The groove shape can ensure a normal tooth profile up to the base of the sun gear 22.

Further, as shown in FIG. 4, during integral molding,
When the ring-shaped stepped projections 24 are formed on the sun plate 21 so as to surround the bases of the three planet shafts 23 and connect the planet shafts 23, the surface of the sun plate 21 on the planet shaft 23 side is formed. It is possible to prevent the grease injected in the vicinity of the central portion of the above from flowing outward due to the centrifugal force when the solar plate 21 rotates, by the step of the step-like convex portion 24.

The integrally-formed planetary shaft of this embodiment is 3
It is a book, but as shown in FIG. 5, by forming the other three planetary shafts 23b every other position at different radii from the center of the solar plate 21, one integral molded product,
It is possible to obtain outputs of different specifications by providing a total of 6 planetary shafts, one set of three, and selecting one set of every other planetary shaft. As shown in FIG. 5, if recesses 23c are formed at the tips of every other planet shafts 23b having different radii, every other type becomes easy.

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

In this embodiment, the preceding deceleration stage A is composed of three stages as shown in FIG. 2 (one stage is omitted in FIG. 1), and the lowermost stage (in FIGS. 1 and 2) is the preceding stage. Each of the planetary gears 25 at the reduction stage has an input gear 29 fixed to a drive shaft 28 of a motor 27 inserted through a hole 26a in the center of the lid 26.
And is meshed with an internal gear 31 on the inner peripheral surface of a cylindrical internal gear case 30 and revolves around the input gear 29 while rotating within the internal gear 31.

The planetary gears 25 of the preceding deceleration stage on the upper side are meshed with the sun gear 22 of the preceding stage and also meshed with the internal gear 31, and the sun gear while rotating in the internal gear 31. Orbit around 22.

Further, the disk-shaped output plate 32 having a mounting hole 32a in the center, and the output plate 32 vertically projecting from equidistant positions on the same circumference of the surface of the output plate 32 on the front deceleration stage A side are provided. The planetary shaft 33 is a sintered metal in which a metal (for example, pure iron) powder is pressure-molded and sintered, and then impregnated with an impregnating agent (oil or resin) and pores are sealed. It is molded.

Further, as in the case of the solar plate 21, when integrally molded, the output plate 32 has a thin ring shape so as to surround the roots of the three planet shafts 33 and to connect the planet shafts 33. When the stepped convex portion 34 is formed, the grease injected near the center of the surface on the planetary shaft 33 side flows out due to the centrifugal force when the output plate 32 rotates. Can be prevented and the lubricity can be maintained for a long time.

The sintered metal, in which the output plate 32 and the planetary shaft 33 are integrally formed, has a large number of holes, which are sealed with an impregnating agent (for example, oil or resin). There is. That is, the holes are filled by being impregnated 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 each of the planetary shafts 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 gear stage A, and to the internal gear 31 of the internal gear case 30. It is meshed and revolves around the sun gear 22 while rotating within the internal gear 31.

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

The internal tooth case 30 made of sintered metal is
Although it has a large number of pores, the pores are sealed with an impregnating agent (for example, oil or resin). That is, the holes are filled by being impregnated with oil or resin. If oil is used as the impregnating agent, the exuded oil may flow into the motor 27 or into the built-in equipment, affecting the motor performance or the built-in equipment. Is desirable.

An oil-impregnated bearing 40 is press-fitted and fixed in the hole 38 of the lid portion 30a of the inner tooth case 30.
The output shaft 35 is rotatably housed in a shaft hole 40a at the center thereof, and its tip portion projects outward.

In the screw hole (not shown) at the lower end of the cylindrical portion of the inner tooth case 30, as shown in FIG.
Is screwed with a screw 41a, and as shown in FIGS. 1 and 2, the motor 27 brought into contact with the lower surface of the lid 26 from above in the two screw holes 39 is screwed with a screw 41b.

The rotation of the input gear 29 at the tip of the drive shaft 28 of the motor 27 is transmitted as the reduced rotation of the output shaft 35 through the three stages of the preceding reduction gear A and the final reduction gear B.

Due to the frictional heat generated by the rotation of the output shaft 35, the oil in the oil-impregnated bearing 40 expands and flows out to the shaft hole 40a, 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 it is sealed by being sealed. For this reason, the oil that has flowed out is absorbed into the holes of the oil-impregnated bearing 40 by a capillary phenomenon and returns, and circulates without loss due to the pumping action, so that a seizure phenomenon between the bearing and the output shaft occurs even after long-term driving. Will disappear. In addition, the internal gear case 30 is in contact with the oil-impregnated bearing 40,
Since the holes of the inner tooth case 30 made of sintered metal are also sealed with the resin, oil is not absorbed into the inner tooth case 30,
No oil loss occurs in the oil-impregnated bearing 40.

Further, the inner tooth case 30 made of sintered metal is used.
Since the resin is impregnated and the pores are sealed, the grease applied for smooth engagement between the inner tooth case 30 and the planetary gears 25 and 37 is absorbed into the inner tooth case 30. Therefore, even if the planetary gears 35 and 37 are driven for a long period of time, smooth meshing is maintained, and the planetary gears 35 and 37 are not worn or fallen.

Although the output plate 32 and the inner tooth case 30 are both made of sintered metal in the above embodiment, one of the output plate 32 and the inner tooth case 30 is sealed. Alternatively, the other may be made of a normal metal.

In the above embodiment, the output shaft 35, which is a separate body, is fixed to the output plate 32. However, the output shaft 35 also serves as the output plate 3.
2 and the planetary shaft 33 may be integrally molded.

[0041]

As described above, according to the present invention,
Since either or both of the output plate and the inner tooth case are made of sintered metal that has been sealed, the oil flowing out from the oil-impregnated bearing is not absorbed into the output plate, and the inner tooth case Since grease between the planetary gears will not be absorbed into, the output shaft seizure phenomenon, planetary gear wear,
The tooth collapse phenomenon does not occur, and stable driving for a long time can be realized.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a planetary gear type transmission device 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.

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 cross-sectional view showing the configuration of a conventional general planetary gear type transmission device.

[Explanation of symbols]

 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

Claims (1)

[Claims] 1. A bearing having a shaft hole, an internal gear case having an internal gear formed on its inner peripheral surface, and a sun gear arranged at the center of the bearing-side surface of the sun plate, and the sun plate. A plurality of planet shafts are arranged on the other surface of
At least one pre-deceleration stage in which planetary gears are rotatably fitted to the plurality of planetary shafts, and the output shaft is disposed at the center of the bearing-side surface of the output plate,
A plurality of planetary shafts are arranged on the other surface of the output plate, and a final reduction stage in which planetary gears are rotatably fitted to the plurality of planetary shafts, respectively, and the output shaft is the bearing. Is rotatably fitted into the shaft hole of the final reduction stage and the planetary gear of the final reduction stage meshes with the sun gear of the preceding reduction stage, and the final reduction stage and the preceding reduction stage are inside the internal gear case. In the planetary gear type transmission device, which is incorporated, wherein the planetary gears of the final reduction stage and the preceding reduction stage mesh with the internal gears of the internal gear case to revolve while rotating and revolving, the output plate and the internal teeth A planetary gear type transmission device, characterized in that both or one of the cases is made of a sintered metal sealed with an impregnating agent.