Patent Application
20120103128
1. Technical Field
The present disclosure relates generally to articulated robots, particularly, to a parallel robot.
2. Description of Related Art
A parallel robot is extensively used in flight simulation and wave simulation. Many parallel robots include a fixed platform, a moveable platform, and six chains positioned in parallel between the fixed platform and the moveable platform. The six chains can have a fore and aft motion, with each chain including a prismatic joint and two ball joints connected to the fixed platform and the moveable platform respectively. Under a moving synergy of the six chains, the moveable platform can be moved in six degrees of freedom relative to the fixed platform.
However, a ball head and a socket are always connected via the ball joint. A space always exists between the ball head and the socket because of insufficient machining and/or assembling precision. The ball head and the socket are easily scoured, and a vibration of the moveable platform occurs. Thus, a movement stability and a location precision of the parallel robot is decreased, making the parallel robot unsuitable for high precision applications.
Therefore, there is room for improvement within the art.
The components in the drawings are not necessarily drawn to scale, the emphasis instead placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
Referring to
In the illustrated embodiment, the six chains 30 have three positioning relationships as follows:
(1) The six first ball joints 40a connected to the fixed platform 10 are divided into three groups of first ball joints 401a. Each group of the first ball joints 401a includes two first ball joints 40a positioned adjacently, and the three groups of first ball joints 401a are positioned in trisection portions of a circular periphery of the fixed platform 10;
(2) The six second ball joints 40b connected to the moveable platform 20 are divided into three groups of second ball joints 401b. Each group of the second ball joints 401b includes two second ball joints 40b positioned adjacently, the three groups of second ball joints 401b are positioned in trisection portions of a circular periphery of the moveable platform 20;
(3) The three groups of first ball joints 401a and the three groups of second ball joints 401b are positioned in six equal portions of a circular periphery in a stagger manner.
In the illustrated embodiment, the second ball joints 40b are similar to the first ball joints 40a.
Referring to
The first flange 412 defines a plurality of first installation holes 4121 around a centre of the first flange 412 allowing the threaded connecting members (not shown) to pass through and connect with the first connecting member 31 or the second connecting member 32. An oblique connecting surface 424 is formed on a side of the second flange 422 away from the socket 421. The connecting surface 424 defines a plurality of second installation holes 4223 utilized for allowing threaded connecting members (not shown) to pass through and connect with the fixed platform 10 or the moveable platform 20. The socket member 42 is oblique relative to the fixed platform 10 or the moveable platform 20 after mounting on the fixed platform 10 or the moveable platform 20.
The resilient pressing mechanism 50 further includes a plurality of fixing rings 52 positioned on a periphery portion of the first flange 412 and the second flange 422 which is convenient for mounting and adjusting the springs 51. Each end of each spring 51 forms a hook 512 corresponding to each fixing ring 52. Each fixing ring 52 includes a ring body 521 and a connecting portion 522 formed integrally. The first flange 412 defines a plurality of first fixing holes 4122, and the second flange 422 defines a plurality of second fixing holes 4224 corresponding to the first fixing holes 4122. The connecting portions 522 engage with the first fixing holes 4122 and the second fixing holes 4224 to fix the fixing rings 52 to the first flange 412 and the second flange 422. The hooks 512 can conveniently hang on the fixing rings 52 respectively for mounting or changing the springs 51.
Under a moving synergy of the six chains 30, the moveable platform 20 has six degrees of freedom relative to the fixed platform 10. The number of the chains 30 may be different according to the desired of freedom of motion for the moveable platform 20. For example, the number of the chains 30 may be two to five. The ball member 41 maintains solid contact with the socket member 42 during use depending on the compression applied by the resilient pressing mechanism 50. Even if a space is produced during assembly or abrasion, a space between the ball member 41 and the socket member 42 is diminished or eliminated because of the compression. Thus, movement stability and location precision of the moveable platform 20 are improved.
The ball member 41 can further include an oil hole 414 defined in a longitudinal direction. The oil hole 414 is a through hole with one end of the oil hole 414 extending to a surface of the head 411 matching with the socket 421, and another end of the oil hole 414 extending to the first flange 412, sealed by a sealing member 415 (referring to
Referring to
It should be appreciated that the second ball joints 40b may not be similar to the first ball joints 40a, as long as the pre-compression provided by the resilient pressing mechanism 50 can tightly connect the ball member 41 to the socket member 42, and can diminish or eliminate the space produced between the ball member 41 and the socket member 42.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010521427.8 | Oct 2010 | CN | national |
