Double-acting pulsation damper system for a motor vehicle

Abstract

The presented system for automotive vehicles comprises a double-acting pulsation damper with a hydraulic damper that can receive hydraulic oil at two ports. A pump supplies oil via two lines and pressurizes the damper. Between the damper and the pump is a pulsation damper with a pressure chamber divided into two spaces by a movable separating piston. Each space contains a spring that preloads the piston. An actuator allows this preload to be adjusted to optimally adapt the damping system. The piston is adjustable using the actuator to allow for the additional preload.

Description

[0001] The present invention relates to a double-acting pulsation damper system in a motor vehicle.

[0002] Today's high-priced vehicles must meet ever-increasing demands on chassis quality and chassis adjustability.

[0003] To meet these requirements, hydraulically adjustable active suspension systems are used in particular. To adjust the suspension to a rebound or compression stage, hydraulic pistons are pressurized in different directions by a hydraulic pump. Such pumps often lead to fluid pulsations in hydraulic systems.

[0004] Fluid pulsations consist of pressure spikes that can be caused by a rapid change in flow velocity through a hydraulic pump within supply lines or by the sudden closure of a valve. The effects can lead to significant damage to the elements of hydraulically adjustable suspension. To protect the system from fluid pulsations and vibrations, pulsation dampers can be used that can adapt to the operating conditions of the hydraulic pump.

[0005] US 2022 / 0 154 798 A1 discloses a vibration damper with a working cylinder which is divided by an axially movable piston on a piston rod into a first and a second working chamber filled with a damping medium, wherein the vibration damper has at least one compensating accumulator for receiving the damping medium displaced by the piston rod, wherein between the two working chambers there is a flow connection in which a pump arrangement is integrated which has a fluctuation in the delivery volume with a constant power supply, wherein in addition to the at least one compensating accumulator within the flow connection at least one pulsation accumulator is arranged, the volume and spring rate of which is matched to the frequency of the fluctuation in the delivery volume of the pump arrangement.

[0006] DE 10 2022 213 103 A1 discloses a vibration damper having a cylinder in which a piston rod is guided axially movably by a piston, and the piston divides the cylinder into a working chamber on the piston rod side and a working chamber remote from the piston rod, both of which are filled with damping medium, wherein damping medium can be supplied to at least one of the working chambers of the vibration damper, wherein the vibration damper is connected to a pulsation damper for damping non-uniform damping medium supplies, characterized in that the pulsation damper, which is formed by an elastomer element, is arranged in at least one of the working chambers.

[0007] The pulsation accumulator disclosed in the prior art is rigid in its setting and cannot be adapted to changing conditions in the operation of the chassis of the motor vehicle.

[0008] It is therefore an object of the invention to provide a solution which can be adaptively adapted to necessary requirements.

[0009] For this purpose, the invention provides a double-acting pulsation damper system for a motor vehicle according to claim 1. Advantageous embodiments can be found in the subclaims and the description.

[0010] The invention relates to a double-acting pulsation damper system for a motor vehicle, comprising a hydraulic damper, wherein the hydraulic damper comprises a first connection and a second connection, wherein the first connection and the second connection are designed for the supply or discharge of hydraulic oil, wherein a hydraulic pump is provided and designed to supply the hydraulic oil to the hydraulic damper at its first connection via a first line or at its second connection via a second line and thus to pressurize the hydraulic damper, wherein a pulsation damper is arranged between the hydraulic damper and the hydraulic pump, wherein the pulsation damper comprises a pressure chamber with a first connection and a second connection, wherein the first connection of the pressure chamber is connected to the first line and wherein the second connection of the pressure chamber is connected to the second line,wherein a separating piston is displaceably arranged in the pressure chamber and, depending on its position, divides the pressure chamber into a first sub-chamber and a second sub-chamber, wherein a first spring is arranged in the first sub-chamber and a second spring is arranged in the second sub-chamber, so that the separating piston is pre-tensioned in the pressure chamber by the first spring and the second spring, wherein the position of the separating piston of the pressure chamber of the pulsation damper is actively adjustable via an actuator, whereby an additional pre-tension can be applied to the separating piston in the pressure chamber.

[0011] The hydraulic damper can be bidirectionally pressurized by the hydraulic pump via the first and second ports. For this purpose, the hydraulic pump can be configured to rotate in different directions, thereby changing the pressure direction.

[0012] In an advantageous embodiment, the pulsation damper is arranged close to the hydraulic pump to effectively eliminate vibrations emanating from the hydraulic pump. For this purpose, the pulsation damper can be arranged between the hydraulic pump and the hydraulic damper.

[0013] If the first line is operated as the low-pressure side and the second line is operated as the high-pressure side, a pressure level of the hydraulic damper can be set via this.

[0014] The compression stage of a hydraulic damper can refer to the phase of the damping process in shock absorbers or struts in motor vehicles, during which the vehicle wheel is pressed against the vehicle body and the damper is compressed. This can occur, for example, when driving over a bump. During the compression stage, at least two damper valves in the damper pistons of the hydraulic damper can regulate the flow of hydraulic oil to generate the damping forces that dampen the movement of the hydraulic damper, thus improving ride comfort and roadholding.

[0015] If the second line is operated as the low-pressure side and the first line is operated as the high-pressure side, a rebound stage of the hydraulic damper can be adjusted.

[0016] The rebound stage of a hydraulic damper refers to the phase in which the damper is extended. This can occur, for example, when the vehicle's wheel enters a depression and moves downwards away from the body.

[0017] During rebound, valves in the hydraulic damper control the flow of hydraulic oil from one chamber of the hydraulic damper to the other. Resistance caused by the restriction of the hydraulic oil flow slows the movement of the hydraulic cylinder, thus preventing the wheel from compressing too much or the vehicle from reverberating.

[0018] Correctly adjusting the compression and rebound damping of a hydraulic damper is crucial for ride comfort and vehicle control. A hydraulic damper that's set too softly can cause the vehicle to bounce excessively after hitting bumps, while a hydraulic damper that's set too hard can negatively impact ride comfort and lead to unstable handling.

[0019] In an advantageous embodiment, the first sub-chamber is connected to the first connection of the pulsation damper and the second sub-chamber is connected to the second connection of the pulsation damper.

[0020] In an advantageous embodiment, the additional preload allows the separating piston to be deflected from a neutral position between the first spring and the second spring. For this purpose, the separating piston can comprise a drive rod.

[0021] In a further advantageous embodiment, the separating piston can seal the first subchamber from the second subchamber against the hydraulic oil.

[0022] In a further embodiment, the first spring and / or the second spring is designed as a multi-stage spring.

[0023] A multi-stage spring, sometimes referred to as a progressive spring, is a design element whose force absorption and release characteristics vary over the spring's travel. Such springs can be designed so that they do not respond to load in the same way across their entire length. This is often achieved by varying coil spacing within the spring, with alternating areas of narrower and wider coils. At a light load, the area with the wider coil spacing acts first, resulting in a comparatively gentle suspension response. As the load increases, the denser coil sections gradually come into play, increasing the overall stiffness of the spring, resulting in a harder and more stable suspension.Alternatively or additionally, different wire diameters or profiles can be used along the length of the spring to achieve the progressive characteristic. The advantage of multiple spring stages can be their flexible adaptability to different loads.

[0024] In a further advantageous embodiment, the pressure chamber comprises a first inner end wall and a second inner end wall, wherein: a) the first connection of the pressure chamber is connected via an opening in the first inner end wall of the pressure chamber and wherein the second connection of the pressure chamber is connected to the pressure chamber via an opening in the second inner end wall; and / or b) the first spring bears against the first inner end wall and a first side of the separating piston and the second spring bears against the second inner end wall and a second side of the separating piston.

[0025] In a further embodiment, the first connection and the second connection can be arranged on opposite sides of the pressure chamber.

[0026] In a further advantageous embodiment, the at least one diaphragm in the separating piston can be pressure-compensated. The operating pressure in an active hydraulic suspension can be 60–110 bar. The pressure fluctuations can be in the range of 0–4 bar.

[0027] With a pressure-compensated diaphragm, the same pressure can be applied on both sides of the diaphragm in a zero state, so that the diaphragm is unloaded in the zero state.

[0028] In the event of sudden pressure changes, only the differential pressure change from the zero state acts on the diaphragm. Compensation can be achieved, for example, by a bypass hole around the diaphragm, which only allows a defined pressure equalization per unit of time. Thus, rapid pressure changes cannot be compensated, and the diaphragm becomes effective.

[0029] In a further embodiment, the at least one diaphragm in the separating piston can be electromagnetically controlled. For this purpose, the diaphragm can comprise an electromagnet or magnet, which is attracted or repelled by an electromagnet or magnet. This allows, for example, high frequencies to be eliminated by the pulsation damper. For this purpose, the diaphragm can be controlled in phase opposition to the respective frequency.

[0030] In a further advantageous embodiment, the hydraulic pump can be controlled via a frequency converter. A frequency converter can enable a variable speed and direction of rotation of the hydraulic pump.

[0031] In a further embodiment, the double-acting pulsation damper system includes the frequency converter.

[0032] In a further advantageous embodiment, the hydraulic pump comprises the frequency converter

[0033] In a further embodiment, the actuator is an electromagnetic actuator. The electromagnetic actuator can be configured to interact with the separating piston or the drive rod of the separating piston and to adjust the position of the separating piston.

[0034] The electromagnetic actuator and / or the electromagnetically controllable diaphragm can be used to specify a frequency response for the hydraulic damper or the double-acting pulsation damper system with respect to the functional behavior of the double-acting pulsation damper system. This allows different mechanical frequencies to be damped differently. In a further embodiment, the hydraulic damper comprises at least two damper valves, which allow the flow of hydraulic oil into or out of the damper piston to be adjusted.

[0035] The invention also relates to a motor vehicle with a double-acting pulsation damper system, wherein the double-acting pulsation damper system is constructed according to one of the preceding claims, wherein the motor vehicle comprises a body and wherein the pulsation damper is mechanically decoupled from the body of the motor vehicle.

[0036] In an advantageous embodiment, the pulsation damper can be mechanically decoupled from the body via an elastic element.

[0037] Elastic elements can be used to mechanically decouple the pulsation damper from the body of a vehicle or other structure. These can serve to dampen vibrations and reduce the transmission of vibrations and noise. These elastic elements include, among others: rubber mounts and / or vibration dampers and / or elastomer spring elements and / or elastic mats or layers.

[0038] A pulsation damper system can be arranged for each wheel of the motor vehicle.

[0039] The invention is described below purely by way of example with reference to the drawings. It shows: Fig. 1 Double-acting pulsation dampener system.

[0040] Fig.1 shows a double-acting pulsation damper system 100 comprising a hydraulic damper 130, wherein the hydraulic damper 130 comprises a first connection 131 and a second connection 132, wherein the first connection 131 and the second connection 132 are designed to supply or discharge hydraulic oil, wherein a hydraulic pump 140 is provided and designed to supply the hydraulic oil to the hydraulic damper 130 at its first connection 131 via a first line 150 or at its second connection 132 via a second line 155 and thus to pressurize the hydraulic damper 130, wherein a pulsation damper 110 is arranged between the hydraulic damper 130 and the hydraulic pump 140, wherein the pulsation damper 110 comprises a pressure chamber 111 with a first connection 119 and a second connection 120,wherein the first connection of the pressure chamber 111 is connected to the first line 140 and wherein the second connection of the pressure chamber 111 is connected to the second line 145, wherein a separating piston 114 is displaceably arranged in the pressure chamber 111 and, depending on its position, divides the pressure chamber 111 into a first sub-chamber 117 and a second sub-chamber 118, wherein a first spring 112 is arranged in the first sub-chamber 117 and a second spring 113 is arranged in the second sub-chamber 118, so that the separating piston 114 is preloaded in the pressure chamber by the first spring 112 and the second spring 113, wherein the position of the separating piston 114 of the pressure chamber 111 of the pulsation damper 110 can be actively adjusted via an actuator, whereby an additional preload can be applied to the separating piston 114 in the pressure chamber 111.

[0041] The pressure chamber comprises a first inner end wall 121 and a second inner end wall 122, wherein the first port 119 of the pressure chamber 111 is connected to the pressure chamber 111 via an opening in the first inner end wall 121, and wherein the second port 120 of the pressure chamber 111 is connected to the pressure chamber 111 via an opening in the second inner end wall 122. And the first spring 112 bears against the first inner end wall 121 and a first side 115 of the separating piston 114, and the second spring 113 bears against the second inner end wall 122 and a second side 116 of the separating piston 114.

Claims

[1] Double-acting pulsation damper system (100) for a motor vehicle, comprising a hydraulic damper (130), wherein the hydraulic damper (130) comprises a first connection (131) and a second connection (132), wherein the first connection (131) and the second connection (132) are designed for supplying or discharging hydraulic oil, wherein a hydraulic pump (140) is provided and designed to supply the hydraulic oil to the hydraulic damper (130) at its first connection (131) via a first line (150) or at its second connection (132) via a second line (155) and thus to pressurise the hydraulic damper (130), wherein a pulsation damper (110) is arranged between the hydraulic damper (130) and the hydraulic pump (140), wherein the pulsation damper (110) comprises a pressure chamber (111) with a first connection (119) and a second connection (120), wherein the first connection of the pressure chamber (111) is connected to the first line (140) and wherein the second connection of the pressure chamber (111) is connected to the second line (145), where a separating piston (114) is movably arranged in the pressure chamber (111) and, depending on the position, divides the pressure chamber (111) into a first sub-chamber (117) and a second sub-chamber (118), characterized by , that a first spring (112) is arranged in the first partial chamber (117) and a second spring (113) is arranged in the second partial chamber (118), so that the separating piston (114) is prestressed in the pressure chamber by the first spring (112) and the second spring (113), wherein the position of the separating piston (114) of the pressure chamber (111) of the pulsation damper (110) can be actively adjusted via an actuator, whereby an additional preload can be applied to the separating piston (114) in the pressure chamber (111). [2] Double-acting pulsation damper system (100) according to claim 1, characterized by that the first spring (112) and / or the second spring (113) is designed as a multi-stage spring. [3] Double-acting pulsation damper system (100) according to claim 1 or 2, characterized by that the pressure chamber comprises a first inner end wall (121) and a second inner end wall (122), wherein: a) the first connection (119) of the pressure chamber (111) is connected via an opening in the first inner end wall (121) of the pressure chamber (111), and wherein the second connection (120) of the pressure chamber (111) is connected to the pressure chamber (111) via an opening in the second inner end wall (122); and / or b) the first spring (112) bears against the first inner end wall (121) and a first side (115) of the separating piston (114), and the second spring (113) bears against the second inner end wall (122) and a second side (116) of the separating piston (114). [4] Double-acting pulsation damper system (100) according to claim 3, characterized by that the separating piston (114) comprises at least one membrane, wherein the at least one membrane is arranged in at least one recess on the first side (115) of the separating piston (114) and / or second side (116) of the separating piston (114). [5] Double-acting pulsation damper system (100) according to claim 4, characterized by that the at least one membrane in the separating piston (114) is pressure compensated. [6] Double-acting pulsation damper system (100) according to claim 4 or 5, characterized by that the at least one membrane in the separating piston (114) can be controlled electromagnetically. [7] Double-acting pulsation damper system (100) according to one of the preceding claims, characterized by that the hydraulic pump (140) can be controlled via a frequency converter. [8] Double-acting pulsation damper system (100) according to one of the preceding claims, characterized by that the actuator is an electromagnetic actuator. [9] Double-acting pulsation damper system (100) according to one of the preceding claims, characterized by that the hydraulic damper (130) comprises at least two damper valves. [10] Motor vehicle with the double-acting pulsation damper system, wherein the double-acting pulsation damper system (100) is constructed according to one of the preceding claims, wherein the motor vehicle comprises a body and wherein the pulsation damper (110) is mechanically decoupled from the body of the motor vehicle.

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