DE102021002903A1 - Active vibration damping system in a vehicle - Google Patents

Abstract

The invention relates to an active vibration damping system (1) of a wheel suspension (R) of a vehicle with a differential cylinder (2) arranged on a chassis, comprising an inner tube (2.1) and an outer tube (2.2) and a differential cylinder (2) that is in operative connection therewith via a head bearing, on a vehicle body arranged piston rod (4) with a piston (3) which divides the differential cylinder (2) into a lower working chamber (A1) and an upper working chamber (A2), with a movement between the chassis and the vehicle body to a movement of the Piston (3) leads relative to the differential cylinder (2). According to the invention it is provided that - a proportional valve (5) is arranged inside the piston (3) so that the working chambers (A1, A2) can be fluidically coupled to one another when the proportional valve (5) is open, - a circumferential piston band on the piston (3) (10) and a number of ring-shaped permanent magnets (P) provided for driving the piston (3) are arranged, - a stator is arranged between the inner tube (2.1) and the outer tube (2.2), so that an electromagnetic force between the Stator and the permanent magnet (P) on the piston (3) is created ,, - a compression spring (D) running around this section by section is arranged on the piston rod (4) to generate a path-dependent additional force during a rebound movement, - in the foot of the differential cylinder (2) two hydraulic resistors (7, 8) and a number of check valves (6), by means of which the hydraulic resistors (7, 8) are interconnected, arranged in a common housing (11) d are provided for coupling the working chambers (A1, A2) with a hydraulic accumulator (9) and - the housing (11) fluidly connects a hydraulic flow of the outer tube (2.2), a lower working chamber (A1) and the hydraulic accumulator (9) with one another.

Description

The invention relates to an active vibration damping system of a wheel suspension of a vehicle with a differential cylinder arranged on a chassis, comprising an inner tube and an outer tube, and a piston rod with a piston, which is arranged on a vehicle body and which is in operative connection therewith via a head bearing, and which converts the differential cylinder into a lower one Working chamber and an upper working chamber divided, wherein a movement between the chassis and the vehicle body leads to a movement of the piston relative to the differential cylinder.

From the US 2021/0101435 A1 a second electric wheel suspension is known. The second electric wheel suspension includes a second electromagnetic actuator which is arranged between a vehicle body and a wheel of a vehicle and generates a driving force for damping vibrations of the vehicle. The second electromagnetic actuator includes a column rod member and a housing that surrounds the rod member and is capable of moving back and forth in the axial direction relative to the rod member. Housing-side armature coils are provided in the axial direction in the housing, while magnets are arranged in the axial direction in the rod element in such a way that they face part of the housing-side armature coils. The magnets are formed by permanent magnets and electromagnets including rod-shaped armature coils.

In addition, the DE 11 2019 000 948 T5 a damper system for a vehicle including an outer tube, a piston rod, and a piston assembly attached to the piston rod and separating the outer tube into first and second working chambers. A valve assembly attached to the piston assembly controls the flow of fluid between the first and second working chambers. A magnet rotor is attached to the outer tube and extends annularly around the outer tube.

A stator assembly is coupled to the piston rod by a spherical bearing assembly. The stator assembly includes a plurality of coils which, when energized, exert an active damping force on the piston rod. The coils also generate electricity from axial movements of the piston rod relative to the outer tube. One or more slide bearings are arranged radially between the coils and the magnet rotor in a sliding fit in order to stabilize the stator arrangement.

Furthermore, the EP 1 196 300 B1 a suspension system to hold an element in a desired orientation with respect to a reference surface. The suspension system comprises a surface attack means and a suspension unit which is arranged between the surface attack means and the element in order to apply and / or absorb force on and / or from the surface attack means. The suspension unit has a predetermined basic characteristic and is formed by two cylindrical elements, one of which slides in the other in order to form a gas-filled chamber with a variable volume. A series of alternating magnetic pole forming means are provided along the length of one of the cylindrical members and magnetic pole forming armatures are provided near the end of the other cylindrical member, the magnetic poles of one of the cylindrical members being formed from a permanent magnet material. The magnetic poles of one of the cylindrical members are formed by electrical means connected to control means for causing the electrical means to perform a predetermined function and to regulate the pressure of gas in the chamber.

The invention is based on the object of specifying an active vibration damping system for a wheel suspension of a vehicle.

The object is achieved according to the invention by an active vibration damping system which has the features specified in claim 1.

Advantageous refinements of the invention are the subject matter of the subclaims.

An active vibration damping system of a wheel suspension of a vehicle comprises a differential cylinder, which is arranged on a chassis, comprises an inner tube and an outer tube, and a piston rod, which is in operative connection with this via a head bearing and is arranged on a vehicle body, with a piston which converts the differential cylinder into a lower working chamber and a divided upper working chamber, wherein a movement between the chassis and the vehicle body leads to a movement of the piston relative to the differential cylinder. According to the invention, a proportional valve is arranged inside the piston so that the working chambers can be fluidically coupled to one another when the proportional valve is open, the proportional valve being connected to a vehicle electrical system via an electrical line running inside the piston rod. A piston band is arranged circumferentially on the piston and slides along the inner tube, with a number of ring-shaped permanent magnets designed to drive the piston also being arranged on the piston. The inner tube is off an electrically non-conductive material, such as plastic. A stator is arranged between the inner tube and the outer tube, which comprises an iron core and multiphase stator windings and is intended to generate a moving magnetic field, so that an electromagnetic force is created between the stator and the permanent magnets on the piston. On the piston rod there is arranged a compression spring that runs around it in sections to generate a path-dependent additional force during a rebound movement. In the foot of the differential cylinder, two hydraulic resistors and a number of check valves, by means of which the hydraulic resistors are interconnected, are arranged in a common housing and are provided for coupling the working chambers to a hydraulic accumulator and the housing connects a hydraulic flow from the outer tube, a lower working chamber and of the hydraulic accumulator fluidly with one another.

Components of the active vibration damping system form an electromagnetic linear motor, by means of which electromagnetic damping power is provided when the proportional valve is open, since hydraulic damping power is comparatively low when the proportional valve is open.

By means of the linear drive, forces can be generated with relatively high dynamics, as a result of which a vehicle body and a vehicle wheel of the wheel suspension are electromagnetically damped and the electrical energy generated in the process can be fed into a vehicle electrical system.

Depending on a driving situation, the vibration damping system can also generate active forces between the vehicle wheel and the vehicle body via the linear motor, for example in order to support the vehicle body when the vehicle is cornering.

By means of this vibration damping system, the hydraulic damping can be increased continuously, in particular by closing the proportional valve.

Embodiments of the invention are explained in more detail below with reference to drawings.

• 1 schematisch eine Schnittdarstellung eines Schwingungsdämpfungssystems einer Radaufhängung eines Fahrzeuges,
• 2 schematisch einen vergrößerten Ausschnitt eines Differentialzylinders und eines Kolbens des Schwingungsdämpfungssystems,
• 3 schematisch einen Querschnitt des Differentialzylinders und
• 4 schematisch einen weiteren vergrößerten Ausschnitt des Differentialzylinders und des Kolbens des Schwingungsdämpfungssystems.

Show:

• 1 schematically a sectional illustration of a vibration damping system of a wheel suspension of a vehicle,
• 2 schematically an enlarged section of a differential cylinder and a piston of the vibration damping system,
• 3 schematically a cross section of the differential cylinder and
• 4th schematically a further enlarged section of the differential cylinder and the piston of the vibration damping system.

Corresponding parts are provided with the same reference symbols in all figures.

1 shows a sectional view of a vibration damping system 1 a wheel suspension R. a vehicle not shown in detail. In 2 is an enlarged section of a differential cylinder 2 and a piston 3 the vibration damping system 1 shown. A cross section of the differential cylinder 2 indicates 3 and in 4th is another enlarged section of the differential cylinder 2 and the piston 3 shown.

Such a vibration damping system 1 of a vehicle has the essential tasks of keeping vibrations of an unsprung mass, in particular of a chassis, as low as possible, of limiting the vibrations of a sprung mass, i.e. of a vehicle body, to a comfortable level and, in the event of jerky loads, for example when driving into a pothole, absorb mechanical energy in order to protect the vehicle from possible damage.

In general, shock absorber systems with hydraulic damping elements, such as. B. . Chokes and diaphragms, known and comparatively widespread.

Shock absorber systems with electromechanical converters offer the advantage over shock absorber systems with hydraulic damping elements that the mechanical energy can be converted not only into heat, but also into electrical energy that can be made available to the electrical consumers of the vehicle.

The problem with a shock absorber system with an electromechanical converter is currently that a force density of the electromechanical converter is significantly lower than the force density when using hydraulic damping elements.

According to the prior art, an electric motor is therefore used, which has a hydraulic pump with working chambers A1 , A2 of electromechanical shock absorber system is to be connected. Due to a transmission ratio of the pump to the shock absorber, moments of the electric motor can become forces on a piston rod 4th of the shock absorber can be converted. The higher the transmission ratio, the greater the damper forces that can be generated from a comparatively low torque of the electric motor. A disadvantage of a hydraulic translation can be that a mass moment of inertia of the electric motor is coupled to a movement of the shock absorber. A high transmission ratio leads to low dynamics of the shock absorber. If the vehicle wheel is suddenly excited, the shock absorber can harden because the pump and electric motor cannot be accelerated quickly enough.

The following is a combined hydraulic and electromechanical vibration damping system 1 described, by means of which an attempt is made to eliminate the above-mentioned disadvantages and which can be combined with steel springs, air springs and stabilizers of a vehicle.

The vibration damping system 1 , hereinafter referred to as a damper 1 called, includes the differential cylinder 2 , its piston rod 4th with piston 3 is connected to the vehicle body via a head bearing, not shown in detail. The differential cylinder 2 is supported on the chassis, i.e. the unsprung mass. A movement between a vehicle wheel and the vehicle body, i.e. between unsprung and sprung mass, leads to a movement of the piston rod 4th with piston 3 relative to the differential cylinder 2 .

The differential cylinder 2 , which is an inner tube 2.1 and an outer tube 2.2 includes, has the two working chambers A1 , A2 on that by means of the piston 3 are separated from each other.

The two working chambers A1 , A2 , ie a lower working chamber A1 and an upper working chamber A2 , are via a controllable and / or adjustable proportional valve 5 as well as four check valves 6th and two hydraulic resistors 7th , 8th with a hydraulic accumulator 9 connected.

Under the proportional valve 5 is to be understood as a hydraulic valve, the identification of which can be controlled with the help of a magnet via an electric current. The proportional valve 5 can have properties of a throttle, an orifice, a pressure relief valve or a combination of these elements and it can be single-stage or multi-stage, e.g. B. . with pilot control.

At a lower end of the piston 3 is a circumferential piston band 10 arranged, which along the inner tube 2.1 slides. The piston band adjusts 10 is a sealing and guide tape, is formed for example from polytetrafluoroethylene and has a height of z. B. . 8 mm to 10 mm.

In addition, there are a number of ring-shaped permanent magnets P. with a magnetic return made of soft iron on the piston 3 arranged. In one embodiment, the permanent magnets are at a respective end of a stack P. ring-shaped permanent magnets P. arranged halfway up. As an alternative to the illustrated arrangement of annular, radially magnetized permanent magnets P. can also axially magnetized ring-shaped permanent magnets P. with so-called pole pieces or Halbach arrays are used.

Together with in the differential cylinder 2 arranged coils S. form the permanent magnets P. an electromagnetic linear drive with the differential cylinder 2 as the stator and the piston 3 as a sled.

With the proportional valve open 5 can use an oil as hydraulic fluid between the working chambers A1 , A2 largely without resistance due to the open proportional valve 5 be replaced. A hydraulic damping performance of the damper 1 is when the proportional valve is open 5 comparatively low. In such a state, the steam output can take place via the electromagnetic linear drive. This can generate forces with relatively high dynamics and thus electromagnetically dampen the vehicle body and the vehicle wheel. Electrical energy obtained in this way can be fed into a vehicle electrical system. Depending on a driving situation, the damper can 1 The linear motor also generates active forces between the vehicle wheel and the vehicle body in order to support the vehicle body when cornering, for example.

As described above, the power density of an electromagnetic converter is limited, so that a steam output can be too low in a comparatively large number of driving situations.

The proportional valve is used to continuously increase the hydraulic damping 5 closed. This creates a flow resistance between the two working chambers A1 , A2 increases and the oil flows increasingly over the hydraulic resistances 7th , 8th . With the hydraulic resistances 7th , 8th it is tunable, so-called plate-type valves of the usual design, which have the non-return valves 6th are connected in such a way that the oil, which is from the lower working chamber A1 into the upper working chamber A2 flows, by means of a hydraulic resistance 7th is throttled and the oil which from the upper working chamber A2 into the lower working chamber A1 flows by means of another hydraulic resistance 8th is throttled.

By means of the electromagnetic linear drive, damping power is converted into electrical energy and moderate forces can be regulated and / or controlled in a highly dynamic manner, while significantly higher damping forces can be generated via a hydraulic circuit, which are superimposed on the electromagnetic forces.

According to the in 3 The embodiment shown is the damper 1 combined with an air spring to form a shock absorber. Here is the proportional valve 5 inside the piston 3 arranged so that when the proportional valve is open 5 the oil between the two working chambers A1 , A2 can be exchanged. The proportional valve 5 is via an electrical line, not shown, which is inside the piston rod 4th runs to the head bearing, connected to the vehicle electrical system and is controlled and / or regulated via a chassis control unit not shown in detail.

As described above, is on the piston 3 the piston band 10 with the ring-shaped permanent magnets P. arranged with a magnetic yoke made of soft iron.

The inner tube 2.1 of the differential cylinder 2 is made of an electrically non-conductive material, in particular plastic, so that when the piston moves 3 no induction currents in the inner tube 2.1 be generated.

On the piston rod 4th this is partially a compression spring D. , which is also referred to as a rebound stop spring, is arranged to generate a path-dependent additional force during a rebound movement.

In the base of the differential cylinder 2 are the four check valves 6th and the hydraulic resistances 7th , 8th in a common housing 11 arranged. The housing connects 11 Oil flows from the outer tube 2.2 , the lower working chamber A1 and the hydraulic accumulator 9 .

The hydraulic accumulator 9 is designed as an external piston accumulator with the base of the differential cylinder 2 connected is. In addition, is at the foot of the differential cylinder 2 a control unit 12th arranged, which the electrical currents in stator windings W. controls and / or regulates. It is not necessary that the hydraulic accumulator 9 and the control unit 12th lie in one plane. They can also be freely positioned on the outer tube 2.2 of the damper 1 around a vertical axis of the damper 1 be arranged rotated on this.

The differential cylinder 2 is on one of the housing 11 opposite side by means of a lid 13th closed with internal guide and sealing unit.

In addition, the differential cylinder 2 between the inner tube 2.1 and the outer tube 2.2 arranged coils S. as part of the linear drive, for example by means of a three-phase stator winding W. a wandering magnetic field M. generate a magnetic force between the differential cylinder 2 as the stator and the piston 3 to produce as a slide. Alternatively, one- or two-phase stator windings are also possible W. possible.

Instead of a stator with iron-afflicted teeth, an ironless stator can also be used.

An iron core of the stator winding W. is in the longitudinal direction of the damper 1 laminated, i.e. composed of electrical steel sheets, to avoid eddy currents on the stator, i.e. on the differential cylinder 2 to minimize. Instead of using electrical steel sheets, the iron core can also be made from so-called soft magnetic composites (SMC), i.e. soft magnetic powder composite materials.

In the in 3 shown cross section of the differential cylinder 2 are sheet metal packages B. and the rotating stator windings W. shown. The sheet metal stacks fill in the process B. and the stator windings W. does not take up an existing installation space, so that free spaces on the outer circumference Z are formed.

Through these free spaces Z can oil from the upper working chamber A2 of the damper 1 and to the foot of the same and the hydraulic resistances 7th , 8th flow and vice versa. This circulating oil can support heat distribution in the stator.

An iron-core stator can generate cogging torques which are undesirable in relation to a described application, since these inharmonic cogging torques can superimpose the damper forces. The cogging torque can be minimized by a suitable choice of magnetic poles and stator teeth, for example 12 stator teeth on 10 magnetic poles, 15 stator teeth on 14 magnetic poles or 18 stator teeth on 16 magnetic poles. In addition, pole bevels can be used on the permanent magnets P. or be formed on the stator teeth. This is the axial position of the ring-shaped permanent magnets P. or the stator teeth over a circumference of the piston 3 not constant, but varies by a given amount in a linear or sinusoidal manner.

The stator teeth and magnetic poles are in the area of the ring-shaped permanent magnets P. arranged. Outside this area, the stator is continued with the same slot pitch, ie a distance from one stator tooth to the next. Depending on the length of the damper 1 or of the stator, the number of stator teeth can vary.

In addition, the detent moments can be achieved by permanent magnets with a convex shape on one side P. , as in 2 shown can be minimized.

The control unit 12th is connected to the vehicle electrical system by means of a connecting element, in particular a plug. Here is the control unit 12th formed a position of the piston 3 inside the differential cylinder 2 using detected signals from a number of Hall sensors 14th to determine. The hall sensors are for this purpose 14th on an outside of the stator windings W. on a comparatively narrow, elongated plate 15th arranged.

As in 4th is shown, this is done by the Hall sensors 14th flowing magnetic field M. by a position of the permanent magnets P. influenced in strength and direction.

Based on a combined evaluation of the signals recorded by the Hall sensors 14th can change the position of the piston 3 be determined. The position of the piston 3 is a comparatively important input variable for controlling and / or regulating the magnetic field M. . Another comparatively important input variable is an acceleration of the unsprung mass, i.e. the chassis of the vehicle. Therefore, the control unit includes 12th in addition, at least one acceleration sensor, not shown in detail, on the basis of which signals detected an acceleration of the differential cylinder 2 in the longitudinal direction of the can be determined.

On the board 15th can also be arranged at least one temperature sensor, not shown, which by means of a thermally conductive material, for. B. . by means of a thermal paste and / or a thermal pad to which the iron core is thermally coupled.

In addition, a further temperature sensor, also not shown, can be provided, which is surrounded by oil, so that the control unit 12th also a temperature value in the stator and thus in the damper 1 detect and in a control and / or regulation of the electrical currents in the stator windings W. can take into account.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 2021/0101435 A1 [0002]
• DE 112019000948 T5 [0003]
• EP 1196300 B1 [0005]

Claims (3)

Active vibration damping system (1) of a wheel suspension (R) of a vehicle with a differential cylinder (2) arranged on a chassis, comprising an inner tube (2.1) and an outer tube (2.2) and a differential cylinder (2) which is in operative connection therewith via a head bearing and is arranged on a vehicle body Piston rod (4) with a piston (3) which divides the differential cylinder (2) into a lower working chamber (A1) and an upper working chamber (A2), with a movement between the chassis and the vehicle body leading to a movement of the piston (3) relative to the differential cylinder (2), characterized in that - a proportional valve (5) is arranged inside the piston (3) so that the working chambers (A1, A2) can be fluidically coupled to one another when the proportional valve (5) is open, - the Proportional valve (5) is connected to a vehicle electrical system via an electrical line running inside the piston rod (4), - on which piston (3) revolve of the piston band (10), which slides along the inner tube (2.1), - a number of ring-shaped permanent magnets (P) designed to drive the piston (3) are arranged on the piston (3), - the inner tube (2.1) is formed from an electrically non-conductive material, - between the inner tube (2.1) and the outer tube (2.2) a stator, comprising an iron core and multiphase stator windings (W), for generating a moving magnetic field, so that an electromagnetic force between the stator and the permanent magnet (P) is created on the piston (3), - a compression spring (D) surrounding the piston rod (4) is arranged in sections to generate a travel-dependent additional force during a rebound movement, - two hydraulic resistors at the base of the differential cylinder (2) (7, 8) and a number of check valves (6), by means of which the hydraulic resistors (7, 8) are interconnected, arranged in a common housing (11) and used for Coupling of the working chambers (A1, A2) with a hydraulic accumulator (9) are provided and - the housing (11) fluidly connects a hydraulic flow of the outer tube (2.2), a lower working chamber (A1) and the hydraulic accumulator (9) with one another. Active vibration damping system (1) according to Claim 1 , characterized in that the hydraulic accumulator (9) is designed as an external piston accumulator which is fluidically connected to the housing (11) formed in the base of the differential cylinder (2). Active vibration damping system (1) according to Claim 1 or 2 , characterized in that a control unit (12) for regulating and / or controlling electrical currents in the stator windings (W) of the differential cylinder (2) functioning as a stator is arranged in the area of the base of the differential cylinder (2).

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