DE102017205671A1 - Spring arrangement with variable spring constant - Google Patents

Abstract

The invention relates to a spring arrangement (1), in particular designed as a spring arrangement (1) in a spring-damper system, with a main spring (20) and at least one secondary spring package, wherein at least one secondary spring (11) of the at least one secondary spring packet by at least one blocking element (12 ) for setting the total spring rate of the spring assembly (1) can be blocked or blocked.

Description

The invention relates to a spring arrangement, in particular as a spring arrangement in a spring damper system, with a main spring and at least one secondary spring, wherein the Gesamtfederkonstante of the spring assembly is adjustable by the secondary spring.

In spring arrangements, it is advantageous to adjust the spring constant, for example, to produce a different spring behavior in different situations in vehicles. The ride comfort can be improved by a soft spring behavior on an uneven road, such as a dirt road, by a high spring rate and by a hard spring behavior on a flat road, such as a road, by a lower spring rate. A changing vehicle behavior can also be compensated for with changing payload by means of a variable spring rate.

In the prior art, there are already various alternatives for this. The EP 1 734 277 B1 For example, proposes a spring assembly with an elastomeric spring, which has a non-constant spring rate or spring constant. The overall spring constant can be adjusted by limiting the spring travel and thus enforcing load distribution on the springs. However, the elastomer of the elastomeric spring is subject to aging effects, so that the spring constant or spring characteristics of the spring changes due to aging. Due to the changing spring properties high demands are placed on the manufacture and maintenance of the spring assembly, so that it is impractical and expensive in production and maintenance.

The DE 10 2007 015 888 A1 also proposes a spring assembly of two springs, wherein the travel of one of the springs is limited by a slider. Here, however, only the spring travel is not changed but the spring constant of the spring, so that although the spring arrangement results in a different spring behavior, the spring rate or the Gesamtfederkonstante the spring assembly is not targeted and multi-stage adjustable.

The invention is therefore based on the object to overcome the abovementioned disadvantages and to provide a spring assembly that is simple and inexpensive in production and maintenance and their total spring rate and travel is gradually and selectively adjustable.

This object is achieved by the feature combination according to claim 1.

According to the invention for this purpose a spring arrangement, in particular designed as a spring arrangement in a spring-damper system, proposed with a main spring and at least one secondary spring package. The spring arrangement or its spring action is directed along a spring axis. Both the main spring and the at least one secondary spring package are aligned with their spring direction in the direction of the spring axis, so that the total spring travel and the total spring rate or Gesamtfederkonstante from the respective values of the main spring and the at least one secondary spring package adds up. The main spring is designed to perform a main spring work and provide a main spring travel. The at least one sub-spring package is configured to provide an adjustable sub-spring travel that is smaller than the main spring travel and to perform a sub-feather work that is smaller than the main spring work. By the auxiliary spring package an overall spring rate of the spring assembly is adjustable. The at least one secondary spring assembly consists of at least one secondary spring, which is arranged with its spring action in series with a spring action of the main spring, and in each case at least one blocking element. The blocking element is arranged to be displaceable perpendicular to the spring axis, so that the respective, at least one blocking element is displaceable in the direction of the at least one secondary spring of the secondary spring packet and at least partially blocks the secondary spring travel and the spring action of the at least one secondary spring by the displacement or a position achieved by the displacement , Due to the concern of the locking element on the at least one secondary spring and a further element, such as a further secondary spring of the same secondary spring packet, an intermediate disc or a counter element, the entire travel of the at least one secondary spring is blocked or blocked.

The total spring constant D _total results from the main spring constant D _{main spring} and the secondary _spring constant D _Nebenfeder1 to D _NebenfederN , where N is the number of secondary springs: $$1/{\text{D}}_{\text{total}}=1/{\text{D}}_{\text{mainspring}}+1/{\text{D}}_{\text{<figure-callout id="1" label="next spring" filenames="DE102017205671A1\_0003.png" state="{{state}}">next spring</figure-callout>}1}+1/{\text{D}}_{\text{<figure-callout id="2" label="next spring" filenames="DE102017205671A1\_0002.png" state="{{state}}">next spring</figure-callout>}2}+...+1/{\text{D}}_{\text{Besides springs}}$$

If a minor spring is completely blocked, it does not contribute to the overall spring rate, so its reciprocal value is deleted from the above formula.

The at least one blocking element has at least two positions each. An unlocking position in which it does not block the spring action and the spring travel of the respective secondary spring packet and a blocking position in which it completely blocks the spring action and the spring travel of the respective secondary spring packet. Depending on the embodiment, the blocking elements has intermediate positions in which the blocking elements partially blocks or blocks the spring travel and the spring action of the respective secondary spring packet as a function of its position.

In an advantageous embodiment, the main spring is a coil spring and the at least one secondary spring is a plate spring.

Furthermore, the at least one secondary spring packet in an advantageous embodiment comprises two plate springs as secondary springs. The disc springs are mirrored on a radial plane perpendicular to the spring axis radial plane, arranged on top of each other. This advantageous arrangement results in the unloaded state of the plate springs, depending on the orientation of the plate springs, to its center or to its outside a V-shaped gap into which the blocking element to achieve its blocking position can be introduced.

Each secondary spring packet comprises in an advantageous embodiment a group of at least two blocking elements. The locking elements are arranged uniformly in the circumferential direction about the spring axis, so that they support the secondary springs of the secondary spring packet in a state blocking the secondary springs uniformly. If the group comprises two blocking elements, these are located opposite one another, the spring axis between them, or offset by an angle of 180 ° in the circumferential direction about the spring axis to each other. With three locking elements in the group, these are offset from each other by 120 ° in the circumferential direction about the spring axis.

In a further advantageous embodiment, which comprises at least two secondary spring packets, the blocking elements of a plurality of groups of blocking elements, one group of blocking elements each belonging to a secondary spring package, arranged in the circumferential direction about the spring axis X to each other. Furthermore, the locking elements result from their rotation and by the rotation of the groups of locking elements from a plan view, a regular distribution of the locking elements about the spring axis. For example, in two secondary spring packages, the blocking elements of a first group are arranged at 0 ° and 180 °, and the blocking elements of the second group are arranged at 90 ° and 270 °. From the top view results in a uniform distribution of the locking elements of the two groups of locking elements around the spring axis, wherein the locking elements are offset by 90 ° to each other.

The at least one blocking element is arranged on a radially outward or inward facing outer or inner edge portion or in an outer or inner edge region of the at least one secondary spring. In an arrangement of the at least one blocking element on the outer edge portion, the at least one blocking element is controlled by a control element located on the outside of the plate spring in its displacement. In an arrangement of the at least one locking element on the inner edge portion, the at least one blocking element is controlled by a control in its displacement that passes through a recess in the center of the at least one plate spring.

For controlling the displacement perpendicular to the spring axis of the at least one blocking element, an advantageous development of the spring arrangement comprises a control element. The control can be designed differently. For example, the control element can be formed as an electrical, pneumatic, hydraulic or manual in its position to the at least one locking element adjustable mechanical element. Alternatively, the control element may be formed by a plurality of magnets that attract or repel the at least one blocking element to move it to a position.

The control is movably mounted along the spring axis in an advantageous development. The movement along the spring axis is realized by a screwing movement about the spring axis, a rotational movement about the spring axis or a displacement movement along the spring axis in the direction of the spring axis. At its side or side surface facing the at least one secondary spring packet, the control element forms a control surface over at least one section. At least when the control controls the at least one blocking element, the control surface abuts against the blocking element. The control surface is designed to displace the at least one blocking element in a movement of the control element along the spring axis perpendicular to the spring axis. The control is multilevel executable, so a first control surface displacing the at least one blocking element into a first position and a second control surface arranged in the direction of movement of the control element after the first control surface which further displaces at least one blocking element into a second position. The displacement of the locking elements perpendicular to the spring axis is realized by a rotational movement of the control element about the axis of rotation, without a displacement movement of the control element along the axis of rotation. A displacement of the control element along the spring axis can additionally be applied to the prestressing of the spring arrangement. In a rotational movement of the control, the control surfaces of the control in the circumferential direction as formed on the control locking element guides are formed, which are formed in depth so that the locking elements are in a first position of the control in its unlocked position and by a rotation of the control to a first Angle, for example, 90 ° to the spring axis can be brought by a displacement of the locking elements perpendicular to the spring axis in the locked position. The blocking element groups of different sub-spring packets are brought by the vote of the blocking element guides, each controlling a group of blocking elements, successively in the locked position and preserved.

In an advantageous embodiment of the spring arrangement, the control element is a sleeve which is movable about the secondary spring packet or in the secondary spring packet. If the sleeve is displaceable by a displacement movement along the spring axis, the sleeve can be stored in a linear guide. If the sleeve can be moved by a screwing or rotary movement, a spindle-shaped or thread-like guide can be formed on a surface perpendicular to the spring axis in order to displace it by the rotational movement along the spring axis. Alternatively, the sleeve is arranged as an inner sleeve in the secondary spring packet or the secondary spring packets. Advantageously, a damping element, such as a cylinder, of the spring-damper system passes through the sleeve so that the sleeve is movable along the damper system in the direction of the spring axis. By arranging the sleeve as an inner sleeve to a damping element, a particularly space-saving arrangement can be produced.

As an alternative to the sleeve, the control element in a further advantageous embodiment is a pin which is movable along the spring axis through a central passage of the spring assembly. The pin is guided and movable by a linear guide or by a spindle or thread-like guide.

Another advantage is a development in which the control element in the direction of the spring axis on one side has a stop surface perpendicular to the spring axis. The stop surface can be brought to an abutment via an intermediate element on the main spring in order to adjust the spring preload of the main spring. Are all blocking elements brought by the control in its locking or blocking state, the main spring is prestressed by a further movement of the control in the direction of the spring axis by bringing a force on the main spring of the abutment surface and the main spring is thereby compressed.

In an advantageous embodiment of the spring arrangement, the at least one blocking element in a cross section which runs parallel to the spring axis, round, pyramidal or trapezoidal. The at least one blocking element extends at least partially around the spring axis. For example, the at least one blocking element is designed as a ball or as a wedge. In the case of a triangular, pyramid-shaped or trapezoidal design, the surfaces running toward one another run in the direction of the spring axis. The converging surfaces can be formed at an angle to each other so that the surfaces of the locking elements lie flat against the at least one secondary spring in the blocking position.

Also advantageous is a further development of the spring arrangement, in which a sum of the lengths of all secondary springs along the spring axis is less than or equal to a diameter of the at least one secondary spring of the at least one secondary spring packet. The longitudinal dimension of all secondary springs of all secondary spring assemblies corresponds at most to the diameter of the secondary springs of the secondary spring assemblies, so that the secondary springs are maximally square in total in section.

Between the secondary springs within a secondary spring package or between secondary spring packets an intermediate disc can be arranged in an advantageous development, which serves to stabilize the at least one secondary spring, the support of the secondary spring by the at least one blocking element and / or the suspension of the at least one blocking element.

In an alternative embodiment, only a secondary spring package is arranged with a secondary spring designed as a spiral spring to the main spring. The locking elements can be brought between the turns of the secondary spring and thus the coil spring partially blocked.

The control surfaces of the control are formed in a further advantageous embodiment as one or more threads, each receiving at least one locking element. The thread or threads vary in their depth, so that the at least one blocking element is displaced perpendicular to the spring axis during a movement of the control element.

The at least one blocking element is fixed in its position in the direction of the spring axis by a cage or a holding element. The cage can be arranged within the at least one secondary spring package or outside and rotates the secondary spring package completely or in sections. Alternatively, the cage is arranged in the secondary spring package. By a restoring means, the locking elements are without an external force, such as by the control, again movable to its unlocked position or its initial position. The return means is formed by a magnetic, attractive or repulsive force or by a return spring.

Advantageously, a plate spring in one embodiment variant has a spring rate between 500 N / mm and 1500 N / mm.

The spring rates of the secondary springs are equal in an advantageous embodiment, so that the total spring rate is linearly adjustable. Alternatively, the spring rates are different from each other so that the overall spring rate is progressively adjustable.

Advantageously, the spring arrangement has between 1 and 10 secondary springs.

In a method of changing the spring rate and spring preload of a spring assembly, a control is moved a first distance along a spring axis from an unlocked position to an intermediate position. In this case, at least one group of blocking elements is inserted into a respective secondary spring packet and the spring action of the secondary spring packet is initially partially blocked or blocked. Upon movement of the control element from the intermediate position into a blocking position by a second distance along the spring axis, the spring action of the secondary spring packet is completely blocked. After complete blocking of the spring effect of all secondary spring packets, the control can be brought to bear by a further movement about a third distance along the spring axis with a stop surface on the main spring. By a further movement of the control by a fourth distance along the spring axis, the main spring is biased.

The features disclosed above can be combined as desired, as far as this is technically possible and they do not contradict each other.

• 1 eine Federanordnung;
• 2 a bis c jeweils eine Anordnung von Sperrelementen;
• 3 a bis c jeweils eine Detailansicht eines Sperrelements;
• 4 a bis c jeweils eine Stellung einer Federanordnung mit Hauptfedervorspannung;
• 5 a bis c jeweils eine Nebenfederpaketanordnung mit Sperrelementen;

Other advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to FIGS. Show it:

• 1 a spring assembly;
• 2 a to c in each case an arrangement of blocking elements;
• 3 a to c in each case a detailed view of a locking element;
• 4 a to c in each case a position of a spring arrangement with Hauptfedervorspannung;
• 5 a to c in each case a secondary spring packet arrangement with blocking elements;

The figures are exemplary schematic. Like reference numerals in the figures indicate like functional and / or structural features.

1 shows a schematic side view of a spring assembly 1 where the mainspring 20 and the damper system 2 are shown uncut and the three Nebenfederpakete 10 with the two side springs 11 , which are formed by disc springs, the locking elements 12 which are arranged in three groups each belonging to a secondary spring package belonging, and the control 30 are shown in section. The spring arrangement 1 is shown unloaded, wherein the formed as a sleeve control 30 along the spring axis X is brought into a first position in which the locking elements 12, which are each a ball, from the control surface 31 moved from its unlocked position to the locked position. The first group of blocking elements 12, which is assigned to the uppermost secondary spring packet, lies in each case on both secondary springs 11 of the secondary spring package 10 on, so that the spring action or the spring travel of the secondary springs 11 is blocked and their spring rate does not contribute to the overall spring rate of the spring assembly. The remaining blocking elements 12 , the lower two groups of locking elements 12 of the lower two secondary spring assemblies 10 , are not actuated by the controls, so these locking elements 12 are in their unlocked position and the minor springs 11 this Nebenfederpakete 10 to the total spring rate of the spring assembly 1 contribute. The control element 30 forms a stop surface 32 perpendicular to the spring axis X from. Are all blocking elements 12 from the control 30 placed in their respective blocking position, is the stop surface 32 on the counter element 33 the spring assembly on. Upon further movement of the control along the spring axis, the control brings 30 via the stop surface 32, a force on the counter element 33 increases and thereby increases the pressure on the main spring 20 , whereby the spring arrangement 1 is biased.

The 2 a to c each show a minor spring 11 with locking elements arranged thereon 12 in a top view.

In 2 a are four blocking elements 12 90 ° to each other at the center of the secondary spring 11 lying spring axis X arranged twisted. The blocking elements 12 are each formed as a ball.

2 B shows three, each offset by 120 ° about the spring axis X locking elements 12. The locking elements 12 are wedge-shaped in their section and rotate around the secondary spring 11 in the circumferential direction in part. The locking elements 12 are each in a cage section 13 held, the only displacement perpendicular to the spring axis X, in the direction of the center of the diaphragm spring 11 allows. At the Ka 13 is also formed a return means, which is the blocking element 12 returns to the unlocked position when no external force, for example by the control, is applied. The Ka 13 is in 2 B each partially formed around the minor spring and the secondary spring does not rotate completely.

2 c shows a similar arrangement as 2 B , To the minor feather 11 However, there are six mutually offset by 60 ° locking elements 12 arranged by a the minor spring 11 completely circulating Kä 13 being held.

The 3 a to c each show a section of a cut secondary spring package 10, each of two secondary springs 11 is formed. A minor feather 11 is in each case a plate spring, wherein the disc springs are arranged so that they define outwardly a V-shaped gap in which the blocking element 12 can intervene.

In 3 a is between the minor feathers 11 a washer 14 arranged, the stabilization of the secondary springs 11 serves and on which the return means 15 is fixed. The return means 15 is a compression spring, which is the blocking element 12 from the locked position, without applying an external force, presses in the unlocked position. The blocking element 12 is oval in its cross section on the side facing the disc springs side.

The 3 b shows a blocking element 12 , which is triangular in cross-section on the side facing the disc springs side.

The blocking element 12 is in 3 c Trapezoidal in cross section on its side facing the disc springs side, wherein the angle of the converging surfaces corresponds to the angle of the converging surfaces of the disc springs, so that the surfaces of the locking elements 12 and the minor feathers 11 in a locking position of the locking element 12 lie flat on each other.

The spring arrangements 1 in the 4 a to 4 c each show a spring assembly 1 as in 1 where the position of the control 30 and thus the total spring rate and spring preload of the spring assembly 1 varies.

In 4 a is the control 30 in a first position, in which none of the three Nebenfederpakete 10 is locked.

In 4 b is the control 30 in a second position, in which all three Nebenfederpakete 10 locked or blocked by the displacement of the locking elements 12 in their respective blocking position. The stop surface 32 is located on the counter element 33 on, but does not move this or puts no force on it. The main spring 20 is through the control 30 not yet compressed and thus not biased. The main spring 20 has its full travel.

In 4 c is the control 30 in a third position, in addition to the blocking of the secondary spring packets 10 the counter element 33 and all minor spring packages 10 are shifted. By applying a force from the stop surface 32 on the counter element 33 and the associated shift, becomes the mainspring 20 compressed and biased.

The 5 a to c show each Nebenfederpakete 10 each with a group of blocking elements 12 ,

In 5 a are four secondary spring packages 10 arranged on each other, wherein the first and the last secondary spring package 10 each a minor spring 11 include and the two intermediate sub-spring packages 10 two minor springs 11. Each of the minor spring packs 10 is associated with a group of blocking elements 12, wherein the blocking elements 12 of the first and last minor spring package 10 are designed differently than the blocking elements 12 the intermediate Nebenfederpakete 10 , The locking elements of the first and last secondary spring package 10 support the respective secondary spring 11 each against a counter element and not against another secondary spring 11 from.

In 5b are five secondary spring packages 10 arranged with each other, wherein between each of the five secondary spring packets 10 , each consisting of a secondary spring 11, an intermediate disc 14 is arranged. The blocking elements 12 support the respective secondary spring 11 against the washer 14 so that the total spring rate is adjustable in finer levels, as if always two side springs would be locked at the same time.

In 5 c are the blocking elements 12 on the inside of the secondary springs 11 arranged. The blocking elements 12 are of a designed as an inner sleeve control 30 be brought into their locked position. The inner sleeve sees a control surface 31 for shifting the blocking elements 12 in front. The inner sleeve can be arranged around a damping element of the spring-damper system, so that the damping element passes through the cavity in the inner sleeve.

The invention is not limited in its execution to the above-mentioned preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. For example, the at least one blocking element can be permanently arranged on the at least one secondary spring and can be brought into a blocking position by an electrical pulse.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• EP 1734277 B1 [0003]
• DE 102007015888 A1 [0004]

Claims (13)

Spring arrangement (1), in particular designed as a spring arrangement (1) in a spring-damper system, with a main spring (20) and at least one secondary spring packet (10) along a spring axis X, wherein the main spring (20) is adapted to perform a main spring work and provide a main spring travel and the at least one sub-spring package (10) is adapted to provide an adjustable sub-spring travel that is smaller than the main spring travel, and to perform a sub-feathering work that is smaller than the main spring work, and by which an overall spring rate of the spring assembly (1) is adjustable; the at least one secondary spring package (10) each consisting of at least one secondary spring (11), which is arranged with its spring action in series to a spring action of the main spring (20), and in each case at least one blocking element (12) arranged perpendicular to the spring axis X slidably is, so that the respective, at least one blocking element (12) in the direction of at least one secondary spring (11) of the secondary spring packet (10), the secondary spring travel and the spring action of the at least one secondary spring (11) is at least partially blocking, displaceable. Spring arrangement (1) according to the preceding claim, wherein the main spring (20) is a coil spring and the at least one secondary spring (11) is a plate spring. Spring arrangement (1) according to the preceding claim, wherein the at least one secondary spring packet (10) comprises two plate springs as secondary springs and these mirrored on a plane perpendicular to the spring axis X radial plane, are arranged one above the other. Spring arrangement (1) according to any one of the preceding claims, wherein each secondary spring packet (10) comprises a group of at least two locking elements (12) and the locking elements (12) are arranged uniformly in the circumferential direction about the spring axis X. Spring arrangement (1) according to the preceding claim, wherein the blocking elements (12) of a plurality of groups of blocking elements (12) each of a secondary spring packet (10) from a plan view in the circumferential direction around the spring axis X are arranged rotated to each other, so that the locking elements (12) are evenly distributed in a plan view. Spring arrangement (1) according to one of the preceding claims, wherein the at least one blocking element (12) is arranged on a radially outwardly or inwardly facing outer or inner edge portion of the at least one secondary spring (11). Spring arrangement (1) according to one of the preceding claims, wherein the spring arrangement (1) has a control element (30) for controlling the displacement perpendicular to the spring axis X of the at least one blocking element (12). Spring arrangement (1) according to the preceding claim, wherein the control element (30) is movably mounted along the spring axis X, the control element (30) can be moved along the spring axis X by a screwing movement about the spring axis X, a rotational movement about the spring axis X or a displacement movement along the spring axis X, the control element (30) forms on its side facing the at least one secondary spring packet (10) a control surface (31) which bears against the at least one blocking element (12) at least when the at least one blocking element (12) is controlled and is formed to move the at least one blocking element (12) during a movement of the control element (30) along the spring axis X perpendicular to the spring axis X. Spring arrangement (1) according to the preceding claim, wherein the control element (30) is a sleeve which is movable about the secondary spring packet (10) or in the secondary spring package. Spring arrangement (1) according to Claim 9 wherein the control member (30) is a pin which is movable along the spring axis X through a central passage of the spring pack. Spring arrangement (1) according to one of Claims 6 to 10 , wherein the control element (30) in the direction of the spring axis X on one side a stop surface (32) perpendicular to the spring axis X, which is engageable on the main spring (20) to stop to adjust the spring bias of the main spring (20). Spring arrangement (1) according to one of the preceding claims, wherein the at least one blocking element (12) in a cross section parallel to the spring axis X is triangular, round, pyramidal or trapezoidal and extends at least partially around the spring axis X. Spring arrangement (1) according to one of the preceding claims, wherein a sum of the lengths of all secondary springs along the spring axis X is less than or equal to a diameter of the at least one secondary spring (11) of the at least one secondary spring packet (10).

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