JP2002039285A - Planetary gear drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and low costing high performance planetary gear drive capable of maintaining favorable rotation and torque transmission of a planetary gear on a pin supported by a carrier without using lubricant such as grease or incorporating a sliding bearing. SOLUTION: By forming the pin 25 with both end parts supported by the carrier 24 and rotatably supporting the planetary gear 22 from a sintered material having self-lubricity, usage of a lubricant or a sliding bearing becomes unnecessary. By reducing the number of parts, assembly man-hours and parts machining cost are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear device, and more particularly, to a low-cost planetary gear device having good assemblability.

[0002]

2. Description of the Related Art In a planetary gear device, generally, a sun gear and an internal gear are provided coaxially, and one or more sun gears and internal gears are meshed with each other and rotatably supported by a carrier. A structure in which two planetary gears are arranged, one of the sun gear, the carrier and the internal gear is fixed, and the other two are used as input / output shafts to perform functions such as reduction or speed increase.

As a device using such a planetary gear device, for example, a speed reducer combined with a traction drive (friction roller type transmission) is known. This type of reduction gear usually has a configuration in which a traction drive is arranged on the input side and a planetary gear is arranged on the output side, and the rotational power reduced by the traction drive is transmitted to the sun gear to rotate the internal gear. The rotation of the carrier is freely taken out and the carrier that rotatably supports the planetary gear is restricted in its movement.
The rotation of the sun gear is allowed only by the rotation of the sun gear to restrict the revolution, and the rotation of the planetary gear is transmitted to the internal gear.

Incidentally, the planetary gear in the planetary gear device is rotatably supported by a shaft supported by a carrier. However, a relatively large number of planetary gears are used in combination with a traction drive as in the above example. When components are installed in a narrow space, a structure is adopted in which the planetary gear is rotatably supported by sliding contact with a pin fixed to the carrier in consideration of its assembling property and cost.

Here, when the planetary gear is rotatably supported on a pin of the carrier by sliding contact, when a normal metal material is used for the pin, galling or seizure occurs at a sliding contact portion between the planetary gear and the pin. This is likely to occur, causing not only a decrease in the efficiency of the transmission torque, but also a breakage. Therefore, in order to prevent the occurrence of such inconveniences, conventionally, a lubricating material such as grease is filled in a portion supported by the pins of the planetary gear, or is constantly supplied, or between the planetary gear and the pin. It was necessary to take measures such as incorporating sliding bearings.

[0006]

In the conventional planetary gear device, when a lubricant such as grease is charged or supplied, a sealing mechanism and a supplying mechanism for the lubricant are required, and the number of parts is reduced. In addition to the increase, a space for mounting a seal mechanism or the like is required. On the other hand, when a sliding bearing is interposed, a sealing mechanism or the like is not required, but similarly, the number of parts increases and the number of assembling steps increases. There is a problem in that the cost in the component processing step increases, for example, it is necessary to strictly control the dimensions of the fitting portion in order to fix.

[0007] The present invention has been made in view of such circumstances, without using a lubricant such as grease.
Without incorporating a sliding bearing, it is possible to maintain good rotation and torque transmission on the pin of the planetary gear,
It is an object of the present invention to provide a compact and low-cost planetary gear device having high performance.

[0008]

In order to achieve the above object, a planetary gear device according to the present invention meshes between a sun gear and an internal gear arranged around the sun gear, and
In a planetary gear device provided with a planetary gear rotatably supported by a carrier, the planetary gear is rotatably supported by slidingly contacting a pin provided on the carrier. It is characterized by being formed of a self-lubricating sintered material.

An object of the present invention is to achieve a desired object by providing a self-lubricating property to a pin which supports a planetary gear so as to be slidable and rotatable. When formed of a material, the rotation of the planetary gear can be maintained at a good level on the pin without using a lubricant such as grease as in the case of using a sliding bearing, and compared with the case of using a sliding bearing. In addition, it is not necessary to control the fitting dimension between the planetary gear and the slide bearing, and the number of assembly steps can be reduced because the number of parts does not increase.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a configuration of an embodiment of the present invention, and shows an example in which the present invention is applied to a speed reducer combining a planetary gear device and a traction drive.

In this example, the traction drive 1
Is mainly composed of a sun roller 11, a planetary roller 12, an outer ring 13, and a roller carrier 14 that rotatably supports the planetary roller 12.
, And the outer ring 13 is slightly deviated from the rotation center axis of the sun roller 11 so as to form a wedge-shaped annular space between its inner peripheral surface and the outer peripheral surface of the sun roller 11. It is fixed to the fixing member 4 at the position. A plurality of planetary rollers 12 are arranged between the sun roller 11 and the outer ring 13. With this configuration, when the sun roller 11 rotates, the planetary roller 12 revolves around the sun roller 11 while rotating. Since the planetary roller 12 is rotatably supported by the roller carrier 14, the roller carrier 14 rotates by the revolution of the planetary roller 12. The roller carrier 14 is fixed to the sun gear 21 of the planetary gear device 2 by press-fitting or the like. Therefore, the rotational power input from the input shaft 3 is reduced by the traction drive 1 and The light is transmitted to the sun gear 21 of the gear device 2.

The planetary gear device 2 mainly includes a sun gear 21, a planetary gear 22, an internal gear 23, and a carrier 24 that rotatably supports the planetary gear 22. The carrier 24 is composed of a pair of flat plate members, a gear carrier plate 24a and a backup plate 24b. The outer edge of the gear carrier plate 24a is fixed to the fixed member 4 together with the outer ring 13 of the traction drive 1, and Is fixed to the fixed shaft 6 by welding. The backup plate 24b has an outer peripheral end fixed to the fixing member 4 like the gear carrier plate 24a, and the planetary gear 22 includes a pin 25 having both ends fixed to these plates 24a and 24b.
Slidably supported with respect to.

In the above configuration, the rotation of the sun gear 21 transmitted via the traction drive 1 is transmitted to the internal gear 23 via the planetary gear 22 meshing with both the sun gear 21 and the internal gear 23. That is, since the carrier 24 is fixed to the fixing member 4 as described above, the planetary gear 22 can rotate but cannot revolve. Therefore, when the sun gear 21 rotates, the planetary gear 2
The internal gear 23 rotates at the same time as the 2 rotates. And
The internal gear 23 is fixed to an output housing 5 rotatably supported by a fixed shaft 6 via a rolling bearing 7, and the rotation of the internal gear 23 is taken out to the outside via the output housing 5. .

The pin 25 that rotatably supports the planetary gear 22 is formed of a self-lubricating sintered material. This sintering material is, for example, a sintering material such as an iron-based or copper-based material, which is previously impregnated with gear oil. A plurality of oil grooves 25a are formed on the outer peripheral surface of the pin 25 along the axial direction.

According to the above embodiment, the planetary gear 22
Is slidably supported on the pin 25 having self-lubricating properties, so that good rotation with respect to the pin 25 can be maintained without using a lubricant such as grease. Moreover, since no slide bearing is interposed between the planetary gear 22 and the pin 25, dimensional control for fitting and fixing the slide bearing to the planetary gear is unnecessary. Pin 2
Forming 5 from a sintered material means that the shape of the pin 25 can be selected relatively freely, and the degree of freedom in the shape of the support at both ends of the pin 25 with respect to the gear carrier plate 24a and the backup plate 24b increases. As a result, there is an advantage that the degree of freedom in design is also increased.

In the above embodiment, an example is shown in which the present invention is applied to a speed reducer combining a traction drive and a planetary gear set. However, the present invention is not limited to this, and the present invention is relatively compact. Of course, the present invention can equally be applied to a planetary gear device requiring low cost.

[0017]

As described above, according to the present invention, the pins supported by the carrier of the planetary gear device and rotatably supporting the planetary gears are formed of a self-lubricating sintered material. It is possible to maintain good rotation of the planetary gear without filling or steadily supplying a lubricant such as grease around it, and, furthermore, as in the case where a sliding bearing is interposed between the planetary gear and the pin, It is not necessary to manage the dimensions for fitting and fixing the slide bearing to the planetary gear. Therefore, according to the present invention, it is possible to reduce the number of parts, the number of assembly steps, and the processing cost of parts.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traction drive 11 Sun roller 12 Planetary roller 13 Outer ring 14 Roller carrier 2 Planetary gear device 21 Sun gear 22 Planetary gear 23 Internal gear 24 Carrier 24a Gear carrier plate 24b Backup plate 25 Pin 25a Oil groove 3 Input shaft 4 Fixing member 5 Output housing 6 Fixed shaft 7 Rolling bearing

Claims (1)

[Claims] 1. A planetary gear device provided with a planetary gear meshed with a sun gear and an internal gear arranged around the sun gear and rotatably supported by a carrier, wherein the planetary gear is A planetary gear device, wherein the planetary gear device is rotatably supported in sliding contact with a pin provided on the carrier, and the pin is formed of a sintered material having self-lubricating properties.