JPH0781614B2 - Connection structure of planetary gear unit - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear device coupling structure that has a wide range of applications as a speed reducer and a speed increaser.

[Prior art]

The planetary gear device includes a sun gear, planetary gears 3 to 4, an outer shell internal gear, a carrier, and the like. Since the center of the sun gear and the center of the carrier are on the same axis, the input shaft and the output shaft are on the same line. Easy-to-use speed reducer and speed increaser. When it is desired to have a large reduction gear ratio, it is sufficient to connect two stages, three stages and the planetary gear device in multiple stages. In order to connect the two planetary gear devices, the carrier of the first stage planetary gear device and the sun gear of the second stage planetary gear device must be connected by a joint shaft. In many cases, the sun gear has a shaft hole. The carrier always has a shaft hole. These shaft holes have some sort of inward turning mechanism such as serrations, splines and D holes. Therefore, a joint shaft having an anti-rotation mechanism corresponding to these is prepared, and the joint shaft is inserted into the sun gear shaft hole and the carrier shaft hole to connect the planetary gear units A and B.

[Problems to be Solved by the Invention]

This is convenient when two identical planetary gear units are connected, but there are drawbacks. When the reduction gear ratio is large, the sun gear is small. The sun gear shaft bore is naturally smaller. Two
A large torque is applied to the sun gear at the stage. Then, a strong torque is applied to the thin portion of the joint shaft which is aligned with the sun gear shaft hole, and the joint shaft is easily broken. In order to solve this, the sun gear of the second stage planetary gear device is made as a sun shaft integrated with the sun gear, not as a hole, and the other end of this sun shaft is directly inserted into the second stage carrier shaft hole. It may be possible to think of an improvement that allows it. This eliminates the need for a joint shaft, makes the second stage sun gear stronger, and makes it more robust as a whole. Such advantages can be considered. However, in this case, the first stage planetary gear device has a special sun gear structure, and it can be used only for connecting two stages. It becomes less versatile. To the inventor's knowledge, such a joint structure without a joint shaft has never been made. In general, the planetary gear unit is often used in one stage and may be connected in multiple stages. The special shape of the sun gear is not convenient. After all, it is better to use a joint shaft without overdoing it. It is possible to provide a planetary gear device that can be connected in multiple stages or can be used in one stage, and in the case of connecting in multiple stages, the sun gear portion is robust even when used after the second stage. Is the purpose.

[Means for Solving the Problems]

The connection structure of the planetary gear device of the present invention comprises: a sun gear 1, an appropriate number of planet gears 2 that should mesh with the sun gear 1, an outer shell internal gear 3 that meshes with the sun gear 1, and the planet gear 2 with a planet shaft. A structure for connecting two planetary gear units A and B which are rotatably supported by 5 and a carrier 4 which is rotatably provided. One of the planetary gear units A is provided with a sun gear 1 and a detent mechanism. It has a sun shaft 22 and the other planetary gear set B has a carrier shaft hole 15, and the planetary gear set in the joint shaft hole 41 of the joint shaft 9 having the joint shaft hole 41 and the outer shaft cylinder portion 40. The sun shaft 22 of A is inserted, and the outer shaft cylinder portion 40 of the joint shaft 9 is inserted into the carrier shaft hole of the planetary gear device B.
By inserting it into 15, the planetary gear units A and B are connected. More preferably, the following is preferable. The outer shell internal gear 3 of the planetary gear units A and B has a detent groove 31 on the outer circumference, and a detent groove 34 on the outer periphery and a spacer cylinder 33 having an engaging projection 36. The spacer cylindrical body 33 and the planetary gear units A and B are connected to each other by inserting the engaging protrusion 36 of the spacer cylindrical body 33 into the detent groove 31 of the outer shell internal gear 3.

[Work]

The second stage planetary gear unit has a sun shaft and no shaft hole. This sun shaft has a detent mechanism and does not have an excessive size. This sun shaft can be connected to the shaft hole of any other gear, without sacrificing versatility.
Since the first stage planetary gear unit has a normal form,
It can be used for any purpose. Further, by using the joint shaft, the planetary gear units A, B
Can be easily connected. The second stage sun gear does not have a shaft hole and is a sun shaft having a rotation stopping mechanism at its tip, and therefore is excellent in strength. Since it can be used as a shaft with a thickness around the root circle of the sun gear, it is very strong against twisting torque. Since the joint shaft itself has the outer shaft tubular portion 40 on the outer side and the joint shaft hole 41 on the inner side and transmits the torque to the inside and the outside, no twisting torque is applied. It is a small member, but withstands such forces well. Since the size and shape of the inner and outer anti-rotation mechanisms of the joint shaft 9 are different, they are interposed between the two to prevent the anti-rotation mechanisms from interlocking. Similarly, even in the case of serrations, the modules are different, and sometimes one is serration and the other is D-cut. The inner and outer detent mechanisms are optional. The shapes of the outer shaft tubular portion 40 and the joint shaft hole 41 may be determined so as to match them.

【Example】

FIG. 1 is an exploded perspective view showing a connecting structure of a planetary gear device according to an embodiment of the present invention. FIG. 2 is a vertical sectional view in a connected state. The planetary gear unit A, the planetary gear unit B, the joint shaft 9, and the spacer cylinder 33 are connected. The planetary gear unit itself may have any structure. The planetary gear units A and B have the sun gear 1 at the center. There are three planetary gears 2 that surround and mesh with this. The number of planetary gears may be four. Surrounding all these planetary gears is a shell internal gear 3. The carrier 4 is a combination of a main carrier disc 4a and a sub carrier disc 4b. The carrier 4 rotatably supports the planetary gear 2 by means of a planetary shaft 5. The sub carrier board 4b has three (or four) first convex portions 10 on the inner surface. Corresponding to this, the main carrier board 4 has 3
It has one (or four) second convex portions 11. A plug portion 12 is formed at the tip of the second convex portion 11 of the main carrier board 4a. A socket hole 13 corresponding to this is formed in the first convex portion 10 of the sub carrier board 4b. The plug portion 12 of the main carrier board 4a is inserted into the socket hole 13 of the sub carrier board 4b, and the tip is brought out of the recess 29. Then, the tip of the plug portion 12 is crimped. Due to the caulking end 28, the main carrier board 4a and the sub carrier board 4b
And are integrated. This is the case when the carrier boards 4a, 4b are made of sintered alloy, aluminum die cast, zinc or the like. Carrier board
When 4a and 4b are made of plastic, the ends of the plug portion 12 are fixed by ultrasonic welding. A planetary shaft stop hole 16 is formed on the back surface of the sub carrier board 4b. The planetary shaft stop hole 16 is provided in the middle of the adjacent first convex portions 10. A planetary shaft stop hole 16 is formed on the back surface of the main carrier board 4a. The planetary shaft stop hole 16 is provided in the middle of the adjacent second convex portions 11. Both ends of the planetary shaft 5 are fixed by the planetary shaft stop holes 16 of the main carrier disc 4a and the sub carrier disc 4b. Although the structure of the planetary gear 2 is arbitrary, here, a structure composed of three members will be described. The planetary gear 2 has a planetary gear portion 8 at the center thereof, and planetary disks 6 and 7 on the left and right. The planet shaft 5 is inserted through the shaft through holes 21 in the boss portions of the planet disks 6 and 7. Planetary disks 6, 7 support the planetary gears from both sides. The end of the planetary disk is circular and is larger than the tip circle of the planetary gear. The sun gear 1 of the first stage planetary gear device A may have any shape. This is because a strong torque does not matter. In this example, the sun shaft hole 14 of the D hole is formed. The sun gear of the second stage planetary gear device B does not have a shaft hole, but has a shape in which the gear portion and the shaft are integrally molded.
It is the sun shaft 22 with a rotation stop mechanism. The rotation stop mechanism is a spline in this example. The spline tips are
Slightly smaller than the root circle of the sun gear. Since it can be made almost the same as the root circle, it is strong in strength. The outer shell internal gear 3 can be made of plastic, aluminum or zinc. In this example, it is made of plastic. The outer shell internal gear 3 has an outer shell gear portion 25 at the center and outer shell inner cylindrical surfaces 26, 27 on both sides. The outer shell gear portion 25 meshes with the planetary gear portion. The planetary disks 6 and 7 are brought into contact rolling with the inner cylindrical surfaces 26 and 27 of the outer shell. The outer shell inner cylindrical surfaces 26, 27 are larger than the root circle of the outer shell inner toothed gear. On the outer side of the outer shell internal gear 3, there are eight anti-rotation grooves in the axial direction.
31 is present, and a flat flat cylindrical portion 32 is provided between them. The number of anti-rotation grooves can be changed arbitrarily. In this example, four of the eight detent grooves 31 are used for coupling with the spacer cylinder 33. The remaining four are used for anti-rotation coupling with the casing (not shown). The spacer cylinder 33 is a short plastic cylindrical member. The outer diameter is the same as the outer diameter of the outer shell internal gear 3. On the outer peripheral surface of the spacer cylinder 33, four rotation preventing grooves 34 are bored in the axial direction. At these intermediate positions, four pairs of engaging protrusions 36 are formed on both sides. The engagement projection 36 of the spacer cylinder 33, the rotation-preventing groove 34, and the rotation-preventing groove 31 of the outer shell internal gear 3 are provided so that their phases match. The joint shaft 9 is a short tubular member. The outer shaft tubular portion 40 is formed on the outer side. A joint shaft hole 41 is formed inside.
At one end, there is a collar portion 42 which is larger than the addendum of the outer shaft cylinder portion. The outer shaft cylindrical portion 40 has a rotation stopping mechanism corresponding to the carrier shaft hole, and is inserted into the carrier shaft hole 15. The tip of the sun shaft 22 with a rotation stopping mechanism of the planetary gear device B is inserted into the joint shaft hole 41. Two planetary gear units A and B are connected by the joint shaft 9. The collar portion 42 contacts the back surface of the first-stage carrier 4 and positions the joint shaft 9 in the axial direction. The engaging projections 36 of the spacer cylinder 33 are inserted into the four rotation preventing grooves 31 of the outer shell internal gear 3 of the planetary gear units A and B. Then, the four detent grooves 34, 31 are arranged in an axial line with respect to the planetary gear device A, the spacer cylinder 33, and the planetary gear device B. Since the same detent mechanism is also formed on the casing (not shown), the detent can be prevented only by inserting these three members into the casing. The operation will be described. Connect the power of the motor to the first stage sun gear. Since the outer shell internal gear 3 is fixed, the planetary gear 2 rotates and the carrier 4 rotates at a reduced speed. Since the outer shaft cylinder portion 40 of the joint shaft 9 is inserted into the carrier shaft hole 15, the joint shaft 9 also rotates together with the carrier 4. Since the tip of the sun shaft 22 with the rotation stopping mechanism of the second stage planetary gear device B is inserted into the joint shaft hole 41 of the joint shaft 9, the sun gear 1 rotates. The torque is transmitted radially from the outside to the inside of the joint shaft 9. The torsion torque does not work on the joint shaft 9. A twisting torque is generated between the sun shaft 22 with a rotation stop mechanism and the sun gear 1, but since this portion can be made quite thick (up to the root circle of the sun gear), it can withstand a strong torque. Since the rotational force is transmitted to the second stage sun gear 1 and the outer shell internal gear 3 is fixed, the planetary gear 2 rotates and the carrier 4 decelerates and rotates. When the speed reduction ratios of the planetary gear units A and B are a and b, the overall speed reduction ratio c is given by c = a × b. Although two-stage deceleration has been described here, the same applies to three-stage, four-stage, or more. It can also be used as a multi-speed gearbox.

【The invention's effect】

The two planetary gear devices can be easily connected by the joint shaft 9 having the joint shaft hole 41 and the outer cylinder portion 40. Since the sun gear of the second-stage planetary gear unit is made integral with the sun shaft with the rotation stop mechanism, this portion does not become too thin. The second-stage torque is large, but it can withstand this. Since the second stage sun gear 1 has the sun shaft 22 with a rotation stopping mechanism, the range of use is slightly narrowed, but the versatility is not lost. Since the first stage sun gear has a normal shape with a sun shaft hole,
It is versatile. That is, both the planetary gear units A and B can be used alone or in a multi-stage connection. A rotation stopping groove 31, a spacer cylinder 33 on the outer circumference of the outer shell internal gear 3
If the anti-rotation groove 34 is formed on the outer periphery of the casing so that the phases thereof match, it can be inserted into the casing as it is. With some kind of lid, it is not necessary to fix it with bolts. It is extremely easy to attach and detach to and from the casing.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing members used in a connecting structure of a planetary gear device according to the present invention. FIG. 2 is a vertical cross-sectional view showing the connection structure of the planetary gear device of the present invention. 1 …… Sun gear 2 …… Planetary gear 3 …… Outer shell internal tooth gear 4 …… Carrier 4a …… Main carrier board 4b …… Sub carrier board 5 …… Planetary shaft 6,7 …… Planetary disk 8… … Planetary gear part 9 …… Joint shaft 10 …… First convex part 11 …… Second convex part 12 …… Plug part 13 …… Socket hole 14 …… Sun shaft hole 15 …… Carrier shaft hole 16 …… Planetary shaft Stop hole 17 …… Opening 18 …… Third convex portion 19 …… Fourth convex portion 21 …… Shaft through hole 22 …… Sun shaft with rotation stop mechanism 25 …… Outer shell gear 26, 27 …… Inside outer shell Cylindrical surface 28 …… Caulking end 29 …… Dimple 31 …… Rotation prevention groove 32 …… Flat cylindrical section 33 …… Spacer cylinder 34 …… Rotation prevention groove 35 …… Flat cylindrical section 36 …… Engagement protrusion 40 ...... Outer shaft cylinder part 41 …… Joint shaft shaft hole 42 …… Crim part

Claims (2)

[Claims] 1. A sun gear 1, an appropriate number of planetary gears 2 which should mesh with the sun gear 1, and an outer shell internal gear 3 which meshes with these.
And a planetary gear 2 supported by a planetary shaft 5 and a rotatably provided carrier 4 for connecting two planetary gear devices A and B, which are external to the planetary gear devices A and B. The shell internal gear 3 has a non-rotating groove 31 on the outer periphery,
A spacer cylinder 33 having an anti-rotation groove 34 and an engaging projection 36 on the outer circumference is sandwiched between the planetary gear units A and B to form a spacer cylinder 33.
The connecting structure of the planetary gear unit characterized in that the spacer cylinder 33 and the planetary gear units A and B are coupled by inserting the engaging protrusion 36 of the above into the detent groove 31 of the outer shell internal gear 3. 2. One of the planetary gear devices A has a sun shaft 22 with an anti-rotation mechanism integrated with the sun gear 1, and the other planetary gear device B has a carrier shaft hole 15 and a joint shaft hole 41. The sun shaft 22 of the planetary gear device A is inserted into the joint shaft hole 41 of the joint shaft 9 having the outer shaft cylinder portion 40 and the outer shaft cylinder portion 40 of the joint shaft 9 and the carrier shaft hole 15 of the planetary gear device B. 2. The planetary gear train connecting structure according to claim 1, wherein the planetary gear trains A and B are connected to each other by inserting into the planetary gear train.