DE102015000531B4 - Method for operating a door latch and door latch - Google Patents

Abstract

Method for operating a door latching device (10) for a motor vehicle (38), in which at least one vehicle door (12) moves between a closed position (14) and at least one different latching position (16) and thereby by at least one guide device (18) of the door latching device (10), wherein the vehicle door (12) is held in the at least one detent position (16) by a detent force (FR) exerted by the guide means (18) which is greater than one to move the vehicle door (12) at least one sensor (20) is used by a distance (A) of the at least one vehicle door (12) in its closed position (14) of the one Moving the vehicle door (12) to determine limiting obstacle (22) and depending on the determined distance (A) an opening path (W), which the vehicle door (12) travels between the at least one latching position (16) and the closing position (14), is set by the guide device (18), characterized in that, depending on the determined distance (A) to the obstacle (22), an end opening path (EW is set by the guide means (18) in a final detent position (24) of the vehicle door (12), wherein the vehicle door (12) is held in the final detent position (24) at a predetermined minimum distance (MA) to the obstacle (22) and wherein Minimum distance (MA) is set to the obstacle (22) by means of the door latch (10) in response to an opening speed of the vehicle door (12) to the opening speed dependent vibration amplitudes of the vehicle door (12) in the latching position (16) or the final latching position ( 24) when determining the distance (A).

Description

The invention relates to a method for operating a door latching device for a motor vehicle, in which at least one vehicle door is moved between a closed position and at least one latching position different therefrom, thereby guided by at least one guide device of the door latching device. The vehicle door is held in the at least one detent position by a detent force exerted by the guide device which is greater than a force to move the vehicle door between the closed position and the at least one detent position, the door detent device comprising at least one sensor for determining a distance the at least one vehicle door is designed in its closed position by an obstacle restricting the movement of the vehicle door, an opening path, which the vehicle door travels between the at least one latching position and the closed position being adjustable by means of the guide device, being part of the invention also a corresponding door latching device for a motor vehicle, which is designed to carry out the method according to the invention.

The doors of a motor vehicle usually have a plurality of locking positions, which are distributed uniformly over the entire opening arc between the closed door and the maximum open door. In order to prevent an impact of the driver's door, for example, on another motor vehicle, which is parked in the vicinity of their own motor vehicle, shows US 2008/0294314 A1 a recognition device by means of which obstacles which are located in the region of the opening arc detected and then an opening angle of the vehicle door is limited by means of the device in order to avoid a collision of the vehicle door with the obstacle. For this purpose, the door of the motor vehicle is held by an actuator with a variable force, which limits the rotation of the vehicle door or stops when the door is approached to a predetermined distance to the obstacle.

The publication WO 2006/072315 A1 describes a vehicle door with variable locking function, which holds the vehicle door by introducing a cogging torque via a controllable damper in a desired locking position. The variable locking function acts on the vehicle door within a functional area. The functional area extends to a predetermined opening area between a first opening angle and a maximum opening angle when the vehicle door falls below a predetermined speed or comes to a standstill within the functional area. If the vehicle door is brought to a standstill in any position within the functional range of the variable detent, then the vehicle door is held in exactly this position by a holding moment of the damper. Any detected deflection about the detent position can be clearly assigned to an actuating force, thereby a desire of an operator after turning off the detent is recognizable.

The DE 103 31 466 A1 shows a locking device, by means of which a resistance for opening and / or closing a vehicle door in dependence on the data of a sensor for monitoring the vehicle environment is selected. In contrast to a mere limitation of a door movement, this allows a dynamic adaptation of the resistance to be achieved. Accordingly, for example, an increasing resistance against movement of the door is provided with increasing approach to the obstacle.

The DE 10 2005 023 002 A1 describes a door opening system for motor vehicles, which has respective locking elements, by means of which a further opening of a door of the motor vehicle is prevented as soon as a certain distance is reached to an obstacle located in the pivoting range of the door. For this purpose, the door opening system has a locking device and a controllable actuator, by means of which the door is swung under continuous distance measurement to the obstacle up to a maximum possible opening angle.

Object of the present invention is to provide a method and a door latching device of the type mentioned, by means of which a vehicle door can be operated in an improved manner.

This object is achieved by a method according to claim 1 and a door latching device according to claim 7. Advantageous developments of the invention are given by the dependent claims.

In order to provide a method of the type mentioned, in which a vehicle door can be operated in an improved manner, it is provided according to the invention that depending on the determined distance to the obstacle an Endöffnungsweg a final detent position of the vehicle door is adjusted by the guide means, wherein the Vehicle door is held in the final detent position at a predetermined minimum distance to the obstacle and wherein the minimum distance to the obstacle is set by means of the door latch in response to an opening speed of the vehicle door to the opening speed depending To consider vibration amplitudes of the vehicle door in the latching position or the final detent position in the determination of the distance. While the vehicle door in its closed position delimits the passenger compartment from the surroundings of the motor vehicle, the vehicle door is at least partially opened in its latching position. In the latching position, the door is held by means of the guide device while exercising the latching force. In contrast to the prior art, however, the locking position is not fixed mechanically fixed, but variably adjustable. A conventional guide part, which is often designed as a door brake, only allows a rigid and unchangeable specification of several locking positions, which are usually evenly distributed over an opening arc of the vehicle door. The inventive method starts here and allows continuous positioning of the locking position on the possible within the scope of the kinematic freedom of movement of the vehicle door movement path. The possible movement path corresponds, for example, to the maximum pivoting angle of the vehicle door over the entire opening arc, along which the vehicle door can be moved. In the locking position, the vehicle door is held by a detent force exerted by the guide means, whereby an increased force, which is exerted by the driver on the door handle of the door, for example, is required to move the vehicle door from its latching position. In the latching position, a pivoting of the vehicle door relative to a movement of the vehicle door in an intermediate position different from the latching position is made more difficult. Thus, an unintentional movement of the vehicle door in both directions, ie in the opening direction and in the closing direction, is effectively prevented. Characterized in that the latching position can be adjusted continuously at a predetermined location of the opening arc, the risk of colliding when opening the vehicle door with an obstacle restricting the movement of the vehicle door, particularly curbed. A person moving the vehicle door also receives a particularly pleasant, haptic feedback, since the setting of the opening path between the locking position and the closing position in contrast to the prior art, not the opening of the vehicle door is abruptly prevented or limited, but, for example, the opening path to reach the latching position is shortened. Thus, due to the detection of the obstacle, a smaller pivoting angle is set between the closed position and the latching position than in an obstacle-free motion situation in which no obstacle restricts the movement of the vehicle door. As a result, an adaptive door latch is provided, which allows a vehicle occupant particularly familiar and comfortable moving the vehicle door. The sensor, which is used to determine the distance of the vehicle door in its closed position from the obstacle restricting the movement of the vehicle door, can be part of an existing environmental sensor system of the motor vehicle, that is, for example, part of a Parklenkassistenten. Accordingly, no additional sensor in the form of a distance sensor is required to determine the distance to the obstacle. This can save costs. Furthermore, the sensor can be placed both on the vehicle door, so for example on a side mirror or at another point on the motor vehicle. The only criterion for the sensor positioning is that this is chosen so that with the sensor a possible obstacle in the pivoting range of the vehicle door can be detected safely. However, it is clear that several sensors can be used to detect the obstacle, for example, to detect a moving obstacle, such as a parked neighboring vehicle, even in its relative movement to the own motor vehicle safely. Accordingly, for example, a first sensor for monitoring a front portion of the motor vehicle and a second sensor for monitoring a rear portion are provided, both being adapted to detect the distance to the obstacle and to determine. If the obstacle moves out of a detection range of the first sensor, the second sensor takes over the detection of the obstacle. It is clear that the door latching device has a suitable processing unit, by means of which the distance to the obstacle determined from the sensor data of the sensor or sensors is converted into the opening path and thus into a dependent pivoting angle with which the latching position is set , The vehicle door passes during its movement between the closed position and the obstacle to at least two locking positions, namely to the locking position and the final detent position. By adjusting the two locking positions, an increased force required to open the vehicle door, whereby a person opening the vehicle door is particularly clearly pointed to the obstacle. The latching position and the final detent position, for example, distributed evenly over the available opening path between the obstacle and the closed position of the vehicle door, so be set. In the final locking position, the vehicle door is kept at the predetermined minimum distance from the obstacle. In this case, it is taken into account that, when the latching position or the final latching position is reached, the vehicle door may oscillate depending on the opening speed of the vehicle door, before the vehicle door comes to rest in the latching position or the final latching position and is held motionless there. The minimum distance to the obstacle can thus by means of the door latch also in dependence on the opening speed of the vehicle door be adjusted to account for the opening speed-dependent vibration amplitudes of the vehicle door in the locking position or the final detent position in the determination of the distance. For this purpose, for example, the change of the distance to the obstacle with the time during the pivotal movement of the vehicle door can be detected in a particularly simple manner with the sensor and the opening speed of the vehicle door can be derived therefrom.

It is furthermore advantageous if, in the final latching position, the vehicle door is held by a final latching force exerted by the guide device, which is greater than the latching force with which the vehicle door is held in the latching position. The person who opens the door, thus receives a particularly gentle haptic feedback, since the Endrastkraft is greater than the locking force. Thus, the movement of the vehicle door out of the final detent position requires both in the direction of the obstacle and in the direction of the closed position a higher, exerted on a door handle of the vehicle door force, as to overcome the cogging force. This is a particularly clear indication that there is an obstacle.

It is furthermore advantageous if a position different from a maximum opening position of the vehicle door is set as the final detent position.

The final detent position is to be understood as the last click position, which is clearly noticeable, but can also be overpowered under increased exertion of force. In other words, a manual movement of the vehicle door out of the final detent position in the direction of the obstacle is possible, although this requires an increased effort. This is particularly useful if the obstruction is a ghost target so there is a misdetection by the sensor or, for example, flexible plants are recognized as an obstacle. This may cause the available distance to the obstacle to be determined correctly, but contact with the obstacle would not result in damage. A person opening the vehicle door should therefore continue to have the opportunity to bring the vehicle door in contact with the obstacle. This is particularly advantageous in emergency situations, when it comes to open the vehicle door quickly and leave the vehicle very quickly.

It is also advantageous if, as the latching position, the final latching position is set when the distance is smaller than a predetermined obstacle clearance between the vehicle door in its closed position and the obstacle. The predetermined obstacle distance corresponds to a certain minimum available pivotal range of the vehicle door, below which the final detent position is set as the detent position. This is particularly useful when there is little space to open the vehicle door, because then the locking position and the final detent would have a particularly small distance from each other, which would be distracting by the person moving the vehicle door. If the distance is thus smaller than the predetermined obstacle clearance and, accordingly, the path between the vehicle door in its closed position and the obstacle is particularly small, then the detent position is dispensed with and instead only the final detent position is set in order to facilitate the opening of the vehicle door.

It is furthermore advantageous if a minimum interval between the at least one latching position and the final latching position is predetermined, wherein the at least one latching position and / or the final latching position is set as a function of the minimum interval. The minimum interval corresponds, for example, to a specific, predefinable swivel angle between the latching position and the final latching position. If this minimum interval is undershot, which is the case in particular with a small available opening angle between the vehicle door and the obstacle, then only either the locking position or the final locking position is set. This allows a particularly fast opening of the vehicle door, since then either only the locking force or only the final locking force when moving the vehicle door is overcome. If, however, the minimum interval is exceeded when there is sufficient space to open the vehicle door, then the latching position and additionally the final latching position are set.

The invention also includes a door latching device for a motor vehicle having at least one vehicle door movable between a closed position and at least one detent position and guided by at least one guide device of the door latch device, which is held in the at least one latching position by means of a latching force exerted by the guide device greater than a force to move the vehicle door between the closed position and the at least one latched position. The door latching device comprises at least one sensor which is designed to determine a distance of the at least one vehicle door in its closed position from an obstacle restricting the movement of the vehicle door. An opening path which the vehicle door travels between the at least one latching position and the closed position is adjustable as a function of the determined distance by means of the guide device. Depending on the determined distance to the obstacle is an Endöffnungsweg a final detent position the vehicle door by the guide means adjustable, wherein the vehicle door in the final detent position at a predetermined minimum distance to the obstacle is durable and wherein the minimum distance to the obstacle by means of the door latch in response to an opening speed of the vehicle door is adjustable to the opening speed dependent vibration amplitudes of the vehicle door in the latching position or the final detent position in determining the distance to be considered. The opening travel is adjustable so that the vehicle door is kept in its latching position without contact with the obstacle restricting the movement of the vehicle door. This allows for optimal feedback to exiting vehicle occupants over the space available for opening the vehicle door. The risk of touching obstacles, such as neighboring vehicles can thus be significantly reduced.

It is furthermore advantageous if the guide device is designed as a rotor of an electric linear motor by means of which the movement of the vehicle door can be damped. In order to damp the movement of the vehicle door electrically and thus to achieve the adaptive latching in the latching position and additionally or alternatively in the final latching position, the design of the guide device as a rotor of an electric linear motor is a particularly cost-effective embodiment.

It is also advantageous if the guide device is coupled to a double-acting hydraulic cylinder, by means of which the latching force is adjustable. A double-acting hydraulic cylinder allows a particularly simple damping, depending on which fluid, or which hydraulic fluid is used in the hydraulic cylinder. The adjustment of the latching force by means of the double-acting hydraulic cylinder also takes place particularly quiet, whereby an increased perceived value is achieved when moving the vehicle door.

Finally, it is advantageous if the double-acting hydraulic cylinder is filled with a magnetorheological hydraulic fluid whose damping properties can be set as a function of a magnetic field which can be generated by means of a magnetic field device of the door latching device. The damping properties of the magnetorheological fluid can be adjusted particularly easily by varying the magnetic field that can be generated by the magnetic field device. Furthermore, a stepless adjustment of the damping properties and consequently a particularly comfortable damping is adjustable. The vehicle door can also be held in a particularly simple manner by applying the magnetic field, wherein the overpressure threshold, that is to say the latching force and additionally or alternatively the final latching force, can be metered in particularly accurately by the strength of the magnetic field.

The preferred embodiments presented in relation to the method according to the invention and their advantages apply correspondingly to the door latch device according to the invention and vice versa.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

Further advantages, features and details of the invention will become apparent from the claims, the following description of preferred embodiments and from the drawings.

• 1 eine schematische Darstellung einer Ausführungsform der erfindungsgemäßen Türeinrastvorrichtung;
• 2 eine weitere schematische Darstellung der erfindungsgemäßen Türeinrastvorrichtung; und
• 3 eine schematische Darstellung einer Führungseinrichtung der erfindungsgemäßen Türeinrastvorrichtung.

In the following, the invention is explained once again with reference to a concrete embodiment. This shows:

• 1 a schematic representation of an embodiment of the invention door latching device;
• 2 a further schematic representation of the invention door latching device; and
• 3 a schematic representation of a guide device of the door latch device according to the invention.

1 shows a door latch 10 for a present highly abstracted illustrated motor vehicle 38 , The door latch 10 includes a guide device 18 and one of the guide device 18 guided vehicle door 12 , By means of the guide device 18 is the vehicle door 12 between a closed position 14 and a maximum opening position 26 guided movable. In the maximum opening position 26 is the vehicle door 12 maximum open.

Should now in a tight parking situation, the motor vehicle 38 particularly close to an obstacle designed as a neighboring vehicle in the present exemplary embodiment 22 parked, so there is a danger when opening the vehicle door 12 to the obstacle 22 to initiate. To avoid this, includes the door latch 10 a configured as a distance sensor sensor 20 which is used to determine a distance A of the vehicle door 12 in their closed position 14 from which the freedom of movement of the vehicle door 12 restrictive obstacle 22 is designed. An opening W, which the vehicle door 12 between a latching position 16 and the closed position 14 travels, is dependent on the determined distance A by means of the guide device 10 adjustable. The opening path W corresponds to a pivot angle of the vehicle door 12 , In the latching position 16 becomes the vehicle door 12 by one of the guide means 18 exerted latching force FR held, which is greater than one for moving the vehicle door 12 between the closed position 14 and the latching position 16 force to be applied F. Between the closed position 14 and the latching position 16 is the vehicle door 12 in an intermediate position 15 in which the vehicle door 12 under exercise of the force F is movable. Although the latching force FR is greater than the force F, but a vehicle occupant can still with increased effort on a door handle 13 the vehicle door 12 the vehicle door 12 from the latching position 16 in a final detent position 24 move. Im in 1 the embodiment shown would then the vehicle door 12 with the obstacle 22 collide. The vehicle door 12 is in the final detent position 24 held by a force exerted by the guide device 18 Endrastkraft FE, which is greater than the latching force FR, with which the vehicle door 12 in the latching position 16 will hold. It is clear that the force F, the latching force FR and the final latching force FE, respectively, of the guide means 18 are set here only for the sake of clarity as the door handle 13 expended forces are shown.

2 clarifies in essential parts the contents of 1 why, therefore, only the differences should be discussed. 2 shows how through the guide device 18 depending on the determined distance A to the obstacle 22 an Endöffnungsweg EW of the final detent position 24 of the vehicle door 12 is set, with the vehicle door 12 in the final stop position 24 at a predetermined minimum distance MA to the obstacle 22 is held. This is called the final stop position 24 one from the maximum opening position 26 the vehicle door 12 set different position. In 2 There are two obstacles in the present case 22 represented, which is an obstacle 22 in the distance A to the vehicle door 12 in their closed position 14 is arranged. The other obstacle 22 , which in the present case is shown as a dashed circle, is to be understood as a fictitious obstacle serving here merely for the purpose of clarity, which is at a predetermined obstacle distance HA between the vehicle door 12 in its closed position 14 and the obstacle 22 is arranged. Namely, when the distance A is smaller than the predetermined obstacle distance HA between the vehicle door 12 in its closed position 14 and the obstacle 22 , so is called the latching position 16 the final detent position 24 set. This will get you the vehicle door 12 opening person a particularly clear haptic feedback, based on which the person can recognize that further opening the vehicle door 12 possibly a collision with the obstacle 22 can lead. The latching position 16 and the final detent position 24 So, taking into account the by the sensor 20 detected distance A to the obstacle 22 be adjusted.

Between the locking position 16 and the final detent position 24 is by means of the guide device 18 given a minimum interval MI, wherein depending on the minimum interval MI, the locking position 16 and additionally or alternatively the final detent position 24 is set. Is the distance A to the obstacle 22 big enough, so will the latching position 16 and the final detent position 24 evenly distributed on the Endöffnungsweg EW, wherein the Endöffnungsweg EW present a swivel angle of the vehicle door 12 equivalent. In this uniform distribution, the minimum interval MI corresponds to the half Endöffnungsweg EW. Thus, if the Endöffnungsweg EW, for example, an opening angle of 60 °, the minimum interval MI is an opening angle of 30 °. Is now very little space to open the vehicle door 12 available, for example, if the obstacle 22 in the obstacle clearance HA from the vehicle door 12 in their closed position 14 is arranged, so can only either the locking position 16 or the final detent position 24 be set. If only one of the two locking positions (latching position 16 , Final locking position 24 ), so can the vehicle door 12 be opened under a total of less effort.

The management device 18 may for example be designed as a rotor of an electric linear motor, by means of which the movement of the vehicle door 12 is dampable. Alternatively, the guide means 18, as in one embodiment in 3 shown with a double-acting hydraulic cylinder 28 be coupled, by means of which the force F, the latching force FR and the Endrastkraft FE is adjustable. The double-acting hydraulic cylinder 28 allows a particularly fine adjustment of the force F, the latching force F and the final latching force FE. The double-acting hydraulic cylinder 28 is present with a magnetorheological hydraulic fluid 30 filled, their damping properties in response to a means of a magnetic field device 36 the door latch 10 producible magnetic field H is adjustable. The magnetic field H is on a throttle element 34 which is in a line 32 arranged, aligned. Through the line 32 are present two chambers 31 . 33 the hydraulic cylinder 28 fluidly coupled together. A piston 29 of the hydraulic cylinder 28 is with the leadership facility 18 connected. Alternatively, the piston may also be used as the guide means 18 be formed, provided the double-acting hydraulic cylinder 28 is rotatably mounted and pivoting the vehicle door 12 follows. When moving the piston 29 , by pivoting the vehicle door 12 becomes the hydraulic fluid 30 over the line 32 between the chambers 31 . 33 promoted. In order to control a damping by means of electromagnetism, is the use of the magnetorheological hydraulic fluid 30 especially useful. The advantage of the magnetorheological hydraulic fluid 30 is that the vehicle door 12 can be held with the simple application of the magnetic field H and by the strength of the magnetic field H, both the force F, and the latching force FR and the Endrastkraft FE can be accurately metered.

By means of the double-acting hydraulic cylinder 28 Furthermore, any vibration amplitudes of the vehicle door 12 be steamed.

Claims (9)

Method for operating a door latching device (10) for a motor vehicle (38), in which at least one vehicle door (12) moves between a closed position (14) and at least one different latching position (16) and thereby by at least one guide device (18) of the door latching device (10), wherein the vehicle door (12) is held in the at least one detent position (16) by a detent force (FR) exerted by the guide means (18) which is greater than one to move the vehicle door (12) at least one sensor (20) is used by a distance (A) of the at least one vehicle door (12) in its closed position (14) of the one Moving the vehicle door (12) to determine limiting obstacle (22) and depending on the determined distance (A) an opening path (W), which the vehicle door (12) travels between the at least one latching position (16) and the closing position (14), is set by the guide device (18), characterized in that, depending on the determined distance (A) to the obstacle (22), an end opening path (EW is set by the guide means (18) in a final detent position (24) of the vehicle door (12), wherein the vehicle door (12) is held in the final detent position (24) at a predetermined minimum distance (MA) to the obstacle (22) and wherein Minimum distance (MA) is set to the obstacle (22) by means of the door latch (10) in response to an opening speed of the vehicle door (12) to the opening speed dependent vibration amplitudes of the vehicle door (12) in the latching position (16) or the final latching position ( 24) when determining the distance (A). Method according to Claim 1 characterized in that the vehicle door (12) is held in the final detent position (24) by a final detent force (FE) exerted by the guide means (18) which is greater than the detent force (FR) with which the vehicle door (12) in the Snap position (16) is held. Method according to Claim 1 or 2 characterized in that as the final detent position (24) a position different from a maximum opening position (26) of the vehicle door (12) is set. Method according to one of Claims 1 to 3 , characterized in that as the latching position (16) the final detent position (24) is set when the distance (A) is less than a predetermined obstacle distance (HA) between the vehicle door (12) in its closed position (14) and the obstacle ( 22). Method according to one of Claims 1 to 4 , characterized in that a minimum interval (MI) between the at least one detent position (16) and the final detent position (24) is predetermined, wherein depending on the minimum interval (MI) the at least one detent position (16) and / or the final detent position (24 ) is set. Door latching device (10) for a motor vehicle (38), having at least one vehicle door (12) movable between a closed position (14) and at least one detent position (16) and guided by at least one guide device (18) of the door latch device (10) in which at least one latching position (16) is held by means of a latching force (FR) which can be exerted by the guide device (18), which is greater than one for moving the vehicle door (12) between the closed position (14) and the at least one latched position (16 A force (F) to be expended, wherein the door latching device (10) comprises at least one sensor (20) for determining a distance (A) of the at least one vehicle door (12) in its closed position (14) from moving the vehicle door (12 ) limiting obstacle (22) is designed, wherein an opening path (W), which the vehicle door (12) between the at least one latching position (1 6) and the closing position (14) traversable in dependence on the determined distance (A) by means of the guide device (10) is adjustable, characterized in that in dependence on the determined distance (A) to the obstacle (22) an Endöffnungsweg (EW ) a final detent position (24) of the vehicle door (12) by the guide means (18) is adjustable, wherein the vehicle door (12) in the final detent position (24) at a predetermined minimum distance (MA) to the obstacle (22) preserved and wherein the minimum distance (MA) to the obstacle (22) is adjustable by means of the door latch device (10) in dependence on an opening speed of the vehicle door (12) in order to control opening speed-dependent vibration amplitudes of the vehicle door (12) in the latching position (16). or the final detent position (24) to be considered in determining the distance (A). Door latching device (10) according to Claim 6 , characterized in that the guide device (18) is designed as a rotor of an electric linear motor, by means of which the movement of the vehicle door (12) can be damped. Door latching device (10) according to Claim 6 or 7 , characterized in that the guide means (18) is coupled to a double-acting hydraulic cylinder (28) by means of which the latching force (FR) is adjustable. Door latching device (10) according to Claim 8 , characterized in that the double-acting hydraulic cylinder (28) is filled with a magnetorheological hydraulic fluid (30) whose damping properties in dependence on a by means of a magnetic field device (36) of the door latch (10) can be generated magnetic field (H) is adjustable.

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