JPH05202995A - Power transmission - Google Patents

Abstract

PURPOSE:To certainly block the torque transmission from a output portion and improve transmission efficiency by providing a mechanism to lock the rotation of an output portion and also a mechanism to release the lock of a planetary gear mechanism having its two sections made an input portion and an output portion respectively. CONSTITUTION:When, for instance, clockwise rotating torque is input in an input shaft 5, a planetary gear 2 makes a rotation centering a shaft 6 and transmits counterclockwise rotating torque to an annular gear 3 because respective rotary drums 4, 10 have their clockwise rotation locked by means of a coil spring 23b. An outer ring 12 then enlarges the diameter of the coil spring 23b and simultaneously as the coil spring 23b locks the rotation of the annular gear 3, it releases the lock of a rotation drum 4. This results in transmitting the torque of the input shaft 5 to the output shaft 8 of the rotation drum 4 through the revolution of the planetary gear 2. On the other hand, when, for instance, clockwise rotation torque is input into the output shaft 8, the torque is not transmitted any more because the coil spring 23b locks the rotation of the rotation drum 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in, for example, a steering system of an automobile, and allows transmission of torque from an input portion to an output portion, but prevents transmission of torque from the output portion to the input portion. Regarding the device.

[0002]

2. Description of the Related Art For example, in a rear wheel steering system for a front and rear wheel steering vehicle, a power transmission device is provided between an input shaft and an output shaft, and a tire is formed by unevenness of a road surface or cornering force when the vehicle turns. The load input from is not transmitted to a drive device such as a motor.

As a power transmission device of this type, a device as disclosed in Japanese Patent Laid-Open No. 3-153473 has been conventionally devised.

In this power transmission device, a worm provided on the input side and a worm wheel provided on the output side are meshed with each other, and due to the characteristics of the worm and the worm wheel, only transmission of torque from the input section to the output section is performed. Is to be done. That is, since the worm and the worm wheel have the characteristic that when the torque is input from the worm wheel side, the worm receives the torque due to the friction of the tooth surface, the torque is input from the output side, The output part is locked by the friction between the worm and the worm wheel, and the torque is not transmitted to the input part side.

[0005]

However, in the above-described conventional power transmission device, since the friction between the gears of the worm and the worm wheel is large, most of the torque that is normally input from the input portion side is this. There is a problem in that the power transmission efficiency is low because it is absorbed by friction. Further, in the case of this power transmission device, it is impossible to maintain both high characteristics because both power transmission in one direction (irreversibility) and power transmission efficiency are contrary to each other. Has become.

Therefore, according to the present invention, when the torque is input from the output side, the transmission of the torque to the input side can be surely blocked, and the torque input from the input side is output. It is intended to provide a power transmission device capable of transmitting power to the side with high power transmission efficiency.

[0007]

As means for solving the above-mentioned problems, the present invention provides a planetary gear mechanism comprising a planetary arm supporting a planetary gear and two gears meshing with the planetary gear. While using two nodes as the input part and the output part and providing a lock mechanism to lock the rotation of this output part,
A lock release mechanism is provided to release the lock of the lock mechanism by the torque transmitted to the remaining one node of the planetary gear mechanism.

[0008]

When the torque is input from the input side, the torque is transmitted to the remaining one node to activate the lock release mechanism to release the lock of the output part by the lock mechanism.
As a result, the torque input from the input unit side is transmitted to the output unit side. Further, when the torque is input from the output unit side, the torque is not transmitted to the input unit or the remaining one node because the output unit itself is locked by the lock mechanism.

[0009]

EXAMPLE An example of the present invention will be described below with reference to FIGS.

First, the first embodiment shown in FIGS. 1 to 4 will be described.

In the drawings, 1 is a sun gear, 2 is a planetary gear, 3 is an annular gear, and the planetary gear 2 is rotatably supported by first and second rotating drums 4 and 10 as planetary arms. The sun gear 1, the ring gear 3, and the first and second rotating drums 4 and 10 constitute a planetary gear mechanism, and each of them rotates on the same straight line. In the case of this embodiment, among the three nodes of the sun gear 1, the annular gear 3, and the first and second rotating drums 4 and 10 of the planetary gear mechanism, the sun gear 1 is the input section,
The first and second rotary drums 4 and 10 serve as output parts.

An input shaft 5 is press-fitted into the sun gear 1, and external power is transmitted to the sun gear 1 through the input shaft 5. Plural (for example, three) planetary gears 2 are arranged on the outer circumference of the sun gear 1, and each planetary gear 2 is supported by a shaft 6 whose one end is fixed to the first rotary drum 4 via a needle bearing 7. Further, the output shaft 8 extends at the center of one end face of the first rotary drum 4, and the recess 9 into which the end of the input shaft 5 is loosely inserted at the center of the other end face.
Are formed. Then, a ring-shaped second rotating drum 10 is arranged at an opposing position with the sun gear 1 of the first rotating drum 4 interposed therebetween, and the other end of each shaft 6 supporting the planetary gear 2 is the second rotating drum. It is fixed at 10. The first rotary drum 4 and the second rotary drum 10 are integrally connected through the shaft 6. Deep groove bearings 11a and 11b are press-fitted on the inner peripheral side of the second rotary drum 10, and the input shaft 5 is provided on the inner side of the deep groove bearings 11a and 11b.
Has been press-fitted. As a result, the second rotary drum 10 and the input shaft 5 are rotatable with respect to each other. Further, the first outer ring 12 and the second outer ring 13 are press-fitted on the outer peripheral side of the annular gear 3, and these three members are integrated.

Reference numeral 14 denotes a fixed housing for accommodating the planetary gear mechanism. The fixed housing 14 is tightened by a bolt / nut 17 with a pair of plates 15a and 15b facing each other with a collar 16 interposed therebetween. The input shaft 5 and the output shaft 8 have a fixed structure.
Respectively penetrate the plates 15a and 15b and project to the outside. Circular recesses 18a and 18b are formed on the surfaces of the plates 15a and 15b facing each other, and the ring-shaped fixed drum 1 is provided in each recess 18a and 18b.
9a and 19b are fixed in a fitted state. Predetermined gaps 20a, 20b are formed annularly between the fixed drums 19a, 19b and the peripheral walls of the recesses 18a, 18b,
Further, deep groove bearings 21a and 21b are press-fitted into the inner peripheral surfaces of the fixed drums 19a and 19b, respectively. Each of the deep groove bearings 21a and 21b has an input shaft 5 on the inner side.
The output shaft 8 is press-fitted, and the input shaft 5 and the output shaft 8 are rotatably supported.

From the fixed drum 19b side of the outer peripheral surface of the first rotary drum 4 to the planetary gear 2 side, the large diameter portion 4a and the small diameter portion 4b are stepped as shown in the enlarged view of FIGS. The large diameter portion 12a and the small diameter portion 12b are formed on the inner peripheral surface of the first outer ring 12 correspondingly.
Are formed in steps. A predetermined gap 22b is provided between the outer peripheral surface of the first rotary drum 4 and the inner peripheral surface of the first outer ring 12 so that they do not come into direct contact with each other. On the other hand, the outer peripheral surface of the second rotary drum 10 and the inner peripheral surface of the second outer ring 13 are also formed in a stepped shape, although not shown in an enlarged manner, and a predetermined gap 22a is provided therebetween.

Further, the plate 15 of the fixed housing 14
One coil spring 23b is interposed in a gap 20b between the fixed drum 19b and the fixed drum 19b and a gap 22b between the first outer ring 12 and the first rotary drum 4. In the basic set state, the coil spring 23b has one end in frictional contact with the fixed drum 19b and the other end in the large diameter portion 4a of the first rotating drum 4 and the small diameter portion 12b of the first outer ring 12 as shown in FIG. Is in frictional contact with. Therefore, when the first rotating drum 4 tries to rotate in the diameter reducing direction (the direction in which the diameter of the coil spring 23b is reduced), the coil spring 23b is wound around the fixed drum 19b and the first rotating drum 4 and is wound around the first rotating drum 4. When the first outer ring 12 tries to rotate in the radial direction (the direction in which the diameter of the coil spring 23b is expanded), the rotation of the first rotating drum 4 is prevented as shown in FIGS. 3 and 4.
To contact the large diameter portion 12a of the first outer ring 12 and the plate 15b by friction to lock the rotation of the first outer ring 12 and unlock the first rotating drum 4.

On the other hand, the gap 20a between the plate 15a of the fixed housing 14 and the fixed drum 19a, and the second
Gap 2 between the outer ring 13 and the second rotary drum 10
A coil spring 23a wound in the same direction as the coil spring 23b is interposed in 2a. In the basic set state, one end of the coil spring 23a is also in frictional contact with the fixed drum 19a and the other end is in frictional contact with the second rotating drum 10 and the second outer ring 13.
When 0 tries to rotate in the diameter reducing direction (the direction of reducing the diameter of the coil spring 23a), the rotation of the second rotary drum 10 is locked, and the second outer ring 13 expands in the diameter increasing direction (the diameter of the coil spring 23a is enlarged). Direction), the rotation of the second outer ring 13 is locked and the lock of the second rotary drum 10 is unlocked.

Since both the coil springs 23a and 23b are wound in the same direction and the first rotary drum 4 and the second rotary drum 10 are integrated via the shaft 6, an unlocking force is applied from the outside. If not, the first and second rotary drums 4 and 10 are locked in either the left or right rotation direction. However, the first and second rotary drums 4, 1
When a torque in the direction opposite to the direction in which 0 rotates is applied to the annular gear 3, this torque serves as a lock release force, and the first and second rotating drums 4 and 10 can freely rotate. The mechanism having the coil springs 23a and 23b as the main constituent elements is transmitted to a lock mechanism that locks the rotation of the output portion (first rotating drum 4) and one remaining node (annular gear 3) of the planetary gear mechanism. And a lock release mechanism for releasing the lock of the lock mechanism by the torque.

In the figure, 24 and 25 are interposed between the recess 9 of the first rotary drum 4 and the end of the input shaft 5 in order to keep the meshing position of the sun gear 1 and the planetary gear 2 constant. One end sealed needle bearing and steel ball
Is a shim interposed between the deep groove bearings 21a and 11a in order to keep the gap between the fixed drum 19a and the second rotary drum 10 constant.

Since the power transmission device of this embodiment has the above-described structure, the following is obtained when torque is input from the input shaft 5 side and when torque is input from the output shaft 8 side. The coil springs 23a and 23b may be right-handed or left-handed as long as they are wound in the same direction. The direction of rotation is from the output shaft 8 side,
That is, the direction of rotation viewed from the direction of arrow F in the figure will be described.

1) When torque is input from the input shaft 5 side When torque in the clockwise direction is input to the input shaft 5 from the outside, the first rotary drum 4 and the second rotary drum 10 are initially moved by the coil spring 23b. Since the rotation in the right direction is locked, the planetary gear 2 rotates about the shaft 6 and transmits the torque in the direction opposite to the input shaft 5 to the annular gear 3, that is, in the left rotation direction. Thus, when the torque in the left rotation direction is transmitted to the annular gear 3, the first outer ring 12 integrated with the annular gear 3 expands the coil spring 23b, and the coil spring 23b locks the rotation of the annular gear 3 at the same time. The lock of the first rotating drum 4 is released. As a result, the torque of the input shaft 5 is transmitted to the output shaft 8 of the first rotary drum 4 through the revolution of the planetary gear 2.

When a torque in the counterclockwise rotation direction is transmitted to the input shaft 5 from the outside, the first rotary drum 4 and the second rotary drum 10 are initially locked in the counterclockwise rotation by the coil spring 23a. The planetary gear 2 rotates to transmit rightward torque to the annular gear 3, and the second outer ring 13 integrated with the annular gear 3 expands the coil spring 23a. As a result, the coil spring 23a locks the rotation of the annular gear 3 and at the same time the second rotary drum 10
Then, the torque of the input shaft 5 is transmitted to the output shaft 8 of the first rotary drum 4 through the revolution of the planetary gear 2.

2) When torque is input from the output shaft 8 side When external torque is input to the output shaft 8 in the clockwise direction, the coil spring 23b locks the rotation of the first rotary drum 4. The ring gear 3 and sun gear 1
No torque is transmitted to the (input shaft 5).

When a torque in the counterclockwise rotation direction is input to the output shaft 8 from the outside, the coil spring 23a locks the rotation of the second rotary drum 10, and the annular gear 3 and the sun gear 1 (input Torque is no longer transmitted to the shaft 5).

As described above, in this power transmission device, the transmission of torque from the output shaft 8 side to the input shaft 5 side can be reliably blocked, and the planetary gear mechanism is used. Input shaft 5 with extremely high power transmission efficiency
Torque can be transmitted from the output shaft 8 to the output shaft 8. Furthermore, since the lock and the release of the output shaft 8 can be performed by the mechanism having the coil springs 23a and 23b as main constituent elements, it is possible to cut off a large torque while being small in size.

1 to 4, the coil spring 23 in the basic set state is formed by forming the inner peripheral surfaces of the first and second outer rings 12 and 13 into a stepped shape.
Although b and 23a are surely brought into frictional contact with the first and second outer rings 12 and 13, the inner peripheral surfaces of the first and second outer rings 12 and 13 are straightened as shown in FIG. Alternatively, the coil springs 23b and 23a may be formed to have a large diameter on the side of the ends thereof.

In the case of the one shown in FIGS. 1 to 4, the coil springs 23a and 23b have a diameter gradually increasing from the planetary gear 2 side when the second and first outer rings 13 and 12 rotate in a predetermined direction. Spread the plates 15a, 15b
However, if the coil springs 23a, 23b idle between the plates 15a, 15b and the fixed drums 19a, 19b, the second, first
A loss time is generated before the rotation of the rotary drums 10 and 4 is switched from the locked state to the unlocked state. As a countermeasure for preventing the coil springs 23a and 23b from idling, as shown in FIG.
Coil springs 23a of the outer rings 13 and 12,
The contact portion with 23b is shortened, and the plate 15
The contact portions of the a and 15b with the coil springs 23a and 23b are lengthened, and the coil spring 23
It is conceivable to reduce the diameters of the end portions of the a and 23b on the fixed drum 19a, 19b side, or conversely, increase the diameter of the fixed drums 19a, 19b on the base side. In the case of changing the lengths of the contact portions of the second and first outer rings 13 and 12 and the plates 15a and 15b with respect to the coil springs 23a and 23b, the second outer ring 13 and the plate 15a and the first outer ring 12 and the plate 15b. If the lengths of the respective contact portions are made equal, the lock torque of the second and first outer rings 13, 12 is maximized. When the diameters of the ends of the coil springs 23a and 23b are reduced, the diameters may be reduced stepwise or tapered.

In this way, the coil springs 23a,
When the idling of 23b is prevented, the torque input from the input shaft 5 can be quickly transmitted to the output shaft 8, and rattling that occurs when the rotation direction of the input shaft 5 is continuously switched. Will be kept small.

Further, in the case of the one shown in FIGS. 1 to 4, the first and second outer rings 12, 1 are in use.
3 and the annular gear 3 tilt and the coil springs 23b, 2
There is a possibility that 3a is offset or the meshing of the annular gear 3 is displaced, but as shown in FIG. 7, the drive bush 27 is press-fitted into the fixed housing 14 and the dry bush 27 is used to move the first and second outers. Ring 1
By guiding the rotations of 2 and 13, it is possible to prevent deviation of the coil springs 23a and 23b, deviation of meshing of the annular gear 3 and the like. In this case, a bearing may be used instead of the dry bush 27.

Next, the second embodiment shown in FIG. 8 will be described.

This power transmission device also has a planetary gear mechanism. This planetary gear mechanism rotatably rotates the first sun gear 31, the second sun gear 32, and the planet gear 30 which mesh with the planet gear 30. It is composed of a pair of outer rings 33a and 33b as a supporting planet arm. In the case of this embodiment, these first sun gears 3 of the planetary gear mechanism are used.
1, second sun gear 32, outer rings 33a, 33b
Of the three sections of the first sun gear 31 is the input section, the second
The sun gear 32 serves as an output unit.

The input shaft 5 is press-fitted in the first sun gear 31, and the output shaft 8 is extended in the second sun gear 32. A ring-shaped auxiliary gear 34 having the same diameter as that of the second sun gear 32 is disposed at the opposing position of the second sun gear 32 with the first sun gear 31 interposed therebetween. The peripheral side is rotatably supported by the input shaft 5 via deep groove bearings 11a and 11b. The planetary gear 30 has a structure in which small gears 30b and 30c having the same diameter are integrated on both sides of a large gear 30a. The first sun gear 31 meshes with the large gear 30a, and one small gear 30a has one small gear 30a. Auxiliary gear 34
However, the second sun gear 32 is meshed with the other small gear 30b. Therefore, the auxiliary gear 33 always rotates integrally with the second sun gear 32 via the planetary gear 30. In the figure, 11c is a deep groove bearing interposed between the input shaft 5 and the second sun gear 32.

Further, the fixed housing 14 is composed of a bottomed cylindrical housing body 35a and a plate 35b fixed to the end portion on the opening side thereof. The housing body 35a and the plate 35b are opposed to each other. Concave portions 36a and 36b are formed on the surface of the concave portion 3a.
Ring-shaped fixed drums 19a and 19b are fixed to 6a and 36b, respectively, in a fitted state. Each fixed drum 19a,
Predetermined gaps 20a and 20b are formed in an annular shape between 19b and the peripheral walls of the recesses 36a and 36b, and the input shaft 5 and the output shaft 8 rotate on the inner peripheral surfaces of the fixed drums 19a and 19b. Deep groove bearing 21a for free support,
21b is press-fitted.

On the other hand, the outer rings 33a and 33b are integrated with each other by a shaft 6 that rotatably supports the planetary gear 30, and the outer ring 33a and the auxiliary gear 3 are provided.
4. Predetermined gaps 22a and 22b are formed between the outer ring 33b and the second sun gear 32.

The coil spring 2 is provided in the gap 22a between the outer ring 33a and the auxiliary gear 34 and the gap 20a between the housing body 35a and the fixed drum 19a.
3a is interposed, and a coil spring 23b wound in the same direction as the coil spring 23a is interposed in a gap 22b between the outer ring 33b and the second sun gear 32 and a gap between the plate 35b and the fixed drum 19b. Has been done. One of the coil springs 23a is in a basic set state, one end of which is in frictional contact with the fixed drum 19a, and the other end is in frictional contact with the auxiliary gear 34 and the outer ring 33a.
When 4 tries to rotate in the diameter reducing direction (direction of reducing the diameter of the coil spring 23a), the rotation of the auxiliary gear 34 is locked, and the outer ring 33a rotates in the diameter increasing direction (direction of increasing the diameter of the coil spring 23a). If this is attempted, the rotation of the outer ring 33a is locked and the lock of the auxiliary gear 34 is unlocked at the same time. Further, the other coil spring 23b has one end on the fixed drum 19b and the other end on the second sun gear 3 in the basic set state.
2 and the outer ring 33b are in frictional contact with each other, and when the second sun gear 32 tries to rotate in the diameter reducing direction (the direction of reducing the diameter of the coil spring 23b), the rotation of the second sun gear 32 is locked, When the ring 33b tries to rotate in the radial direction (direction to expand the diameter of the coil spring 23b), the rotation of the outer ring 33b is locked and the second sun gear 32 is unlocked at the same time.

Next, the operation of this power transmission system will be described. In the following, the coil springs 23a,
23b is assumed to be right-handed, and the rotation direction of each component will be described as the rotation direction viewed from the arrow F direction in the drawing.

1) When torque is input from the input shaft 5 side When torque in the right rotation direction is input from the input shaft 5 side, the second sun gear 32 is initially locked in the right rotation by the coil spring 23b. Therefore, the planetary gear 30 revolves in the reverse rotation direction of the input shaft 5, that is, in the left rotation direction, and transmits the torque in the left rotation direction to the outer rings 33a and 33b. Thus, when the torque in the left rotation direction is transmitted to the outer rings 33a and 33b, the coil spring 23b is expanded in diameter and the coil spring 23b locks the rotation of the outer ring 33b and at the same time unlocks the second sun gear 32. Like As a result, the planetary gear 30 rotates, and the torque of the input shaft 5 is transmitted to the output shaft 8 of the second sun gear 32 through the rotation of the planetary gear 30.

When torque in the counterclockwise rotation direction is transmitted to the input shaft 5 from the outside, the auxiliary gear 34 is initially moved to the coil spring 2.
Since the left rotation is locked by 3a, the planetary gear 30 revolves in the right rotation direction and the outer ring 33 rotates.
The torque in the clockwise direction is transmitted to a and 33b. As a result, the outer ring 33a expands the coil spring 23a so that the coil spring 23a locks the rotation of the outer ring 33a and at the same time unlocks the auxiliary gear 34, so that the planetary gear 30 rotates. .. As a result, the torque of the input shaft 5 is transmitted to the output shaft 8 of the second sun gear 32 through the rotation of the planetary gear 30.

2) When torque is input from the output shaft 8 side When external torque is input to the output shaft 8 in the right or left rotation direction, the coil springs 23a and 23b cause the second sun gear 32, Alternatively, the rotation of the auxiliary gear 34 is locked so that torque is not transmitted to the outer rings 33a, 33b and the first sun gear 31 (input shaft 5).

In the power transmission device of the first embodiment shown in FIGS. 1 to 4, the sun gear 1 which is one gear meshing with the planetary gear 2 of the planetary gear mechanism is used as an input portion and a planetary arm. The first and second rotary drums 4 and 10 are used as output parts, and the power transmission device of the second embodiment shown in FIG. 8 includes a first sun gear 31 which is one gear meshing with the planetary gear 30 of the planetary gear mechanism. Although the input unit and the second sun gear 32, which is another gear, are used as the output unit, the embodiment of the present invention is not limited to these,
Any two of the three nodes of the planetary gear mechanism can serve as the input section and the output section.

[0040]

As described above, according to the present invention, any two nodes of the planetary gear mechanism are used as the input portion and the output portion, and the lock mechanism for locking the rotation of the output portion is provided, while the planetary gear mechanism An unlocking mechanism is provided for unlocking the lock mechanism by the torque transmitted to the remaining one node, and the output unit is provided only when the torque is input from the input unit side and the torque is transmitted to the remaining one node. Since it can rotate, torque transmission from the output side to the input side can be reliably prevented. In addition, since torque is transmitted from the input side to the output side through the planetary gear mechanism, the power transmission efficiency is significantly increased compared to the conventional type, and the input and output sections are on the same shaft. It has the advantage that it can be placed on the line.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a portion A in FIG.

FIG. 3 is an enlarged sectional view of a portion A in FIG.

FIG. 4 is an enlarged sectional view of a portion A in FIG.

FIG. 5 is a sectional view showing a modification of the first embodiment.

FIG. 6 is a sectional view showing a modification of the first embodiment.

FIG. 7 is a sectional view showing a modification of the first embodiment.

FIG. 8 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sun gear (gear which meshes with a planetary gear), 2 ... Planetary gear, 3 ... Annular gear (gear which meshes with a planetary gear), 4 ... 1st rotating drum (planetary arm), 10 ... 2nd rotating drum (planetary) arm).

Claims (1)

[Claims] 1. A planetary gear mechanism comprising a planetary arm supporting a planetary gear and two gears meshing with the planetary gear, and any two nodes of the planetary gear mechanism are used as an input portion and an output portion, and rotation of the output portion is locked. A power transmission device comprising a lock mechanism and a lock release mechanism for releasing the lock of the lock mechanism by the torque transmitted to the remaining one node of the planetary gear mechanism.