Electricity: motive power systems – Automatic and/or with time-delay means – Movement – position – or limit-of-travel
Reexamination Certificate
1999-01-11
2001-03-27
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Automatic and/or with time-delay means
Movement, position, or limit-of-travel
C318S264000, C318S265000, C318S266000, C318S286000, C318S400260
Reexamination Certificate
active
06208101
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method for restricting the surplus force of an electrically controlled assembly operated by a foreign force upon contact with an upper or a lower stop position, more particularly on hitting (or contacting) the closing position of a window lifter of a motor vehicle. The method is characterized by a high automatic adaptation to the markedly fluctuating external conditions, such as, temperature and dampness, to which the window lifter is subjected, as well as the compensation of system-conditioned fluctuations, such as scattering of maximum engine torque of an electric motor.
BACKGROUND OF THE INVENTION
From DE 30 34 118 C2, a method is known for the electronic monitoring of the opening and closing process of electrically operated assemblies, such as for example window lifters and sliding roofs of motor vehicles, wherein characteristic values of the assembly are detected and evaluated in a micro computer to ultimately generate setting signals for the electric setting member of the assembly. The aim of this method is to avoid any dangerous jamming of parts of the body and objects, despite the automatic opening and closing of a motor vehicle window. To this end, the process of opening and closing the window is divided into three areas. In order to allow a complete closing of the window pane it is necessary to switch off the system for detecting a jammed state just before the upper edge of the pane could reach the sealing area, otherwise the window pane would reverse. The setting member is thus only switched off when a sensor/electronics system has detected a blocking state of the assembly for a predetermined time period.
With the electric motor being able to develop its maximum torque, the window pane is pressed into the seal with the maximum force available. Surplus forces reach a very high value because the drive has to be designed according to the most unfavorable conditions anticipated. Consequently, tensions arise in the door which can be the cause of wind noises and even untight or loose areas. Also, there is a danger of increased wear on the window lifter mechanism. Furthermore, a stable design of the mechanical loading parts leads to more expensive material and greater weight.
SUMMARY OF THE INVENTION
The object of the invention is therefore to develop a method for restricting the surplus force of an electrically controlled assembly operated by a foreign force on hitting or contacting an upper or a lower stop position. More particularly, restricting the surplus force upon reaching the closing position of a window lifter of a motor vehicle which, through simple cost-effective means, prevents the occurrence of unnecessarily high surplus forces and at the same time safely guarantees reaching the stop position, more particularly the closing position, even when the starting conditions, such as voltage of the energy source, large manufacturing tolerances of the adjustment system and climatic factors, fluctuate quite considerably.
In the present invention, at least one measured value is detected in the inlet area of the stop position and is correlated with the displacement force of the assembly. This measured value is increased through the electronics unit by a predetermined amount (for example relative amount or amount calculated through a functional connection) and is defined as the switch-off criterion so that when this criterion is exceeded or understepped the drive is switched off.
The inlet area is regarded as the displacement area of the assembly which either begins just before reaching the stop position and ends after a following displacement path, or which only begins on reaching the stop position and ends after a further displacement path which causes an elastic deformation of at least a part of the displacement system. The most advantageous design can only be determined when taking into consideration the concrete conditions of each individual case. Determining the amount, more particularly the relative amount, by which the measured value is to be increased for safely reaching the stop position, is best carried out empirically.
In relation to a window pane of a motor vehicle, a characteristic field of measured values is recorded with the variation of the most important measuring factors acting on the movement of the window pane during the closing process and on hitting the lower stop position of the window pane. Such influencing factors are inter alia temperature, dampness, ice and some geometric tolerances which are important for the movement of the pane. From this characteristic field the case should then be selected where the torque requirement to be expected for safely hitting the stop position, more particularly the closing of the window pane, compared with the available torque of the motor, is used up to the greatest possible extent. From the measured values (e.g. electric current, the moment, the period length of the electric motor) correlated with these two torque values, it is possible to obtain a factor for generating the switch-off criterion. If the factor thus obtained for generating the switch-off criterion is then constantly applied to that in the inlet area of the upper and lower stop position, then the window pane is always completely closed and completely opened, respectively.
Naturally, it is possible to obtain a higher degree of adapting the method to the relevant prevailing conditions if the characteristic field, set up by measurements, is provided in the form of a table of values or even in the form of mathematically functional connections in the micro electronics unit.
According to a further variation of the invention, it is proposed to generate the switch-off criterion on the basis of a measured value correlated with: the displacement force before the first contact between the seal and the upper edge of the pane, and a measured value of the displacement force which was detected immediately after the upper edge of the pane entered into the seal.
The sealing area should thereby be no more than 50%. The measured value for the closing area is 25% to 50% of the depth of an inner displacement path of the sealing area in front of the seal. In each case it is to be ensured that the signal evaluation and generation of the switch-off criterion takes place sufficiently quickly. The advantage of the variation just described is that both the sliding properties of the window pane and the sealing properties are included in the calculation.
If crossing through the sealing area offers sufficient time for several measurements inside the seals, then the changing conditions inside the seal can also be measured and considered.
Advantageously, the invention can be used also for electrically controlled window lifters with anti-jam detection because all the pre-requisites for signal detection and signal evaluation are already provided here. When using an electromotor drive, it is readily possible, for example by means of an echo sensor, to use the period length as a correlation value for the displacement force because the motor characteristic field has a clear connection between the speed and torque. Likewise measured values of the electric current could be used for this purpose.
The method can also be used for hitting or contacting the lower stop in a similar way to the variation of the invention just described for closing the window pane. To this end, means are provided which contact the window pane just before the stop position is reached and cause a reduction in the motor speed and thus an increase in the period length. Such means for producing local slow motions can be readily formed as spring elements or elastic damping elements. For elastic damping elements, the inlet area only begins with contact of the damping element and ends after a further displacement path of the displacement system, which causes an elastic deformation of the damping element.
At this point it should be pointed out that the inherent elasticity of several displacement systems, more particularly arm window lifters, is so great that no additiona
Seeberger Jurgen
Ubelein Jorg
Brose Fahrzeugteile GmbH & Co. KG
Christie Parker & Hale LLP
Nappi Robert E.
Smith Tyrone
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