Planetary gear transmission systems or components – Plural power paths to planetary gearing
Patent
1998-10-05
1999-11-30
Ta, Khoi Q.
Planetary gear transmission systems or components
Plural power paths to planetary gearing
475336, 901 26, F16H 128, F16H 3704, B25J 1800
Patent
active
059933488
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a compact gear system of the kind defined in the preamble of claim 1. A compact gear system is constructed to provide a high transmission ratio between an input drive shaft and an output shaft within a small space. Such application is required in the case of industrial robots with which a robot arm is pivotal in relation to a frame and the pivotal movement is achieved with the aid of a drive motor whose rotational speed must be geared down considerably without the assistance of over-bulky transmission devices.
U.S. Pat. No. 1,802,112 teaches a differential type of reduction gear with which very high transmission ratios can be achieved. This reduction gear includes a relatively large number of gear wheels, all of which are conical and require input and output shafts to be mutually perpendicular. Such reduction gears incur high manufacturing costs, take up a relatively large amount of space, and are difficult to adapt to suit different applications.
SE 500 626 teaches a similar gear in which some of these drawbacks are alleviated. This gear, however, also has certain drawbacks. Although the output shaft is hollow, a transverse shaft included in the gear partially blocks the shaft bore and therewith makes it difficult to utilize the space in the hollow shaft. Because it may be advantageous, particularly in the case of industrial robot applications, to use the hollow shaft as ducting for electric cables, different media such as air, water and paint, and other drive shafts, the obstructive transverse shaft constitutes a disadvantage. Furthermore, it is necessary for the input shaft to define a given small angle with the normal plane of the output shaft, which increases the precision required and makes assembly more complicated.
The object of the present invention is to provide a compact gear system of the aforesaid kind in which those drawbacks associated with the known gear systems are avoided.
This object is achieved in accordance with the invention with a compact gear system of the kind defined in the preamble of claim 1 and having the characteristic features set forth in the characterizing clause of said claim.
Because input and output shafts are parallel and connected drive-wise in the given manner, the gear system is simple to assemble, its housing requires working from only one side, and the system is reliable in operation and affords a very compact design. The transmission ratio can be changed with the aid of relatively simple modifications. Furthermore, the gear system takes up none of the space in the hollow shaft, which is extremely beneficial as before mentioned.
It is advantageous to permit the drive gear wheel on the input shaft to drive directly one crown wheel, and to drive the other crown wheel through the medium of an eccentric shaft, therewith enhancing the possibility of obtaining a compact and readily assembled design.
In another preferred embodiment, the gear housing is connected to a robot arm and the output shaft is connected to a frame structure, or vice versa, resulting in an application of the invention where its advantages are of great significance.
These and other advantageous embodiments of the invention will be apparent from the dependent claims.
The invention will now be described in more detail with reference to a preferred embodiment thereof and also with reference to the accompanying drawings, in which
FIG. 1 is a sectional view of an inventive compact gear system;
FIG. 2 is a schematic side view of an industrial robot fitted with an inventive gear system; and
FIG. 3 is a schematic end view of the industrial robot shown in FIG. 2.
FIG. 1 shows the output shaft 1 rotatably journalled in a gear housing 2 by means of bearings 3. The shaft is hollow and has a through-penetrating cylindrical bore 4 that can be used for the passage of electric cables, media, or other drive shafts. The output shaft 1 includes a plurality of pins 5a, 5b, in the illustrated case two pins, which extend in a normal plane radially outwards and which are formed integrally w
REFERENCES:
patent: 140622 (1873-08-01), Gilfillan
patent: 1802112 (1931-04-01), Henderson et al.
patent: 2019343 (1935-10-01), Gaffner
patent: 2390742 (1945-12-01), Setterlund
patent: 4047448 (1977-09-01), Pardo et al.
patent: 4532828 (1985-08-01), Laguardia
patent: 5149310 (1992-09-01), Damino
patent: 5575179 (1996-11-01), Arbrink
Asea Brown Boveri AB
Ta Khoi Q.
LandOfFree
Compact toothed wheel gearing with large gear ratio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compact toothed wheel gearing with large gear ratio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compact toothed wheel gearing with large gear ratio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1665397