Electricity: motive power systems – Positional servo systems – With particular 'error-detecting' means
Patent
1993-12-09
1995-08-22
Ip, Paul
Electricity: motive power systems
Positional servo systems
With particular 'error-detecting' means
318560, 744248R, 414462, 254126, 254 8B, B66F 322
Patent
active
054443482
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates in general terms to the field of robotics, where jacks are used for bringing about reciprocal movement of the articulated elements or for the linear displacement of charges or loads, such as the arms or limbs of a robot. A first main application is for autonomous robots of the walking type or the type having a dynamically controlled suspension. The invention more specifically relates to an electric jack with a rotation-translation movement conversion system and with energy recovery, e.g. of the ball nut-screw type.
DESCRIPTION OF THE PRIOR ART
Among the motor elements used for the actuation of robots, reference can be made to hydraulic and electric jacks. Ever increasing interest is being attached to electric jacks, because hydraulic jacks require a large number of accessories for their operation and cause certain disadvantages due to the use of fluids as transmission elements.
Among the electric jacks, use is made of linear motors, which have an excessively low force/weight ratio to be frequently used in the construction of machines. In addition, they frequently have a limited efficiency.
Use has also been made for a significant time of the screw
ut system for transforming a mechanical rotation energy supplied by an electric motor into a mechanical translation energy. As the screw
ut system is very old, numerous improvements have already been made to it. Thus, numerous electric jacks operate with a ball nut/screw system, i.e. the nut is mounted on the screw by means of balls, somewhat in the same way as the outer ring of a ballbearing mounted on the inner ring by means of a few balls. The latter are located in one or more threads of the screw and are maintained within the nut.
With electric jacks using the ball nut/screw system, it is consequently possible to supply a translation movement with a given force, whereby the electric motor can be automatically controlled as a function of the position of the nut or the force to be supplied. However, in such a ball nut-screw system, the angle of inclination of the thread of the screw is limited in order to enable the jack to supply an adequate force, This arrangement limits the translation speed of the nut and suffers from the supplementary disadvantage of not being or only being slightly mechanically reversible. Thus, by rotating a screw having a limited thread inclination angle, it is easy to displace the nut which is screwed thereto. However, it is generally very difficult or even impossible to turn the screw by pushing or pulling the nut. However, such jacks are used for the displacement of relatively large loads to which the nut is connected. When the latter has reached its maximum speed on the screw during the operation of the jack, it has also acquired an often considerable kinetic energy more particularly due to the load which it is moving. Therefore the irreversibility of the small angle nut/screw system prevents the restoration to the screw of the kinetic energy stored by the load
ut system, when the screw is no longer moving the nut.
The aim of the invention is to propose a jack, e.g. of the ball nut-screw type, in which part of the mechanical energy imparted to the nut is recovered.
SUMMARY OF THE INVENTION
To this end, the main object of the invention is an electric jack mainly comprising at least one rotary electric motor rotating a rotation-translation movement transformation system in order to translate a translation part such as a nut with acceleration and deceleration phases and motor control means for driving the movement transformation system.
According to the invention, it comprises energy recovery means to enable the motor to recover, during the deceleration phases, part of the mechanical energy accumulated on the translation part during the acceleration phases.
When the rotation-translation movement transformation system is a ball nut-screw system, the screw has an angle with an adequate pitch (e.g. exceeding 5.degree.) to permit energy recovery.
Preferably, the screw has several
REFERENCES:
patent: 3671826 (1972-06-01), Newell
patent: 3844535 (1974-10-01), Dorough
patent: 3997143 (1976-12-01), Rose
patent: 4025859 (1977-05-01), Smith
patent: 4067543 (1978-01-01), Orth et al.
patent: 4467250 (1984-08-01), Thomasson
patent: 4496865 (1985-01-01), Allen et al.
patent: 4547692 (1985-10-01), Spaulding
patent: 4712027 (1987-12-01), Karidis
patent: 4733146 (1988-03-01), Hamby
patent: 4969631 (1990-11-01), Whittingham
patent: 5041748 (1991-08-01), Huber
patent: 5075610 (1991-12-01), Harris
patent: 5099161 (1992-03-01), Wolfbauer
patent: 5115181 (1992-05-01), Sood
patent: 5118082 (1992-06-01), Byun
patent: 5223779 (1993-06-01), Palaniapan
patent: 5262706 (1993-11-01), Hollingsworth
patent: 5294874 (1994-03-01), Hessenberger
Commissariat a l''Energie Atomique
Ip Paul
LandOfFree
Electric jack having a rotation-translation movement conversion does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric jack having a rotation-translation movement conversion , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric jack having a rotation-translation movement conversion will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2144170