DE102020101128A1 - Pressure storage system for hydraulic transmission control - Google Patents

Abstract

The invention relates to a pressure accumulator system (10) for hydraulic transmission control, with a longitudinal axis (L), having a housing (12) which extends coaxially to the longitudinal axis (L), the housing (12) at a first housing end (14) an end face (16) and, at a second housing end (18) opposite the first housing end (14), a housing connecting device (20); - a spring arrangement (22) which extends coaxially to the longitudinal axis (L) and which has a first spring end (24) on the end face (16) of the housing (12) is arranged in a counter-bearing manner, and which has a second spring end (26) opposite the first spring end (24); - a piston (28) which extends coaxially to the longitudinal axis (L ), and which with a first piston end (30) at least partially surrounds the second spring end (26) circumferentially and abuts it at the end, and the second piston end (32) opposite the first piston end (30) in the direction of the second Housing end (18) is arranged, and which has circumferentially a groove (34) which is arranged along the longitudinal axis (L) between the first and the second piston end (30, 32); - a sealing arrangement (36) which is circumferentially in the Groove (34) is arranged and which is arranged pressing radially against an inner surface (38) of the housing (12). This enables a compact pressure accumulator system (10) for a transmission control as a volume flow source for leakage compensation.

Description

The invention relates to a pressure accumulator system for hydraulic transmission control, in particular a spring accumulator to be integrated into a valve plate for compensation for Leckagekom.

In principle, spring accumulators which can be integrated in valve plates are known. These are usually used as damping elements and not for leakage compensation. A piston is brought into a defined position by the preloading of a spring and is held in the valve plate with a locking ring. In addition, these damping elements are designed with seal-free pistons. A piston without a seal, however, has the disadvantage that there is always a certain amount of leakage, whereas a piston with any O-ring creates disadvantages in the dynamics of the spring accumulator due to increased friction.

Pressure accumulators, which are used as volume flow sources in hydraulic transmission controls, are usually membrane, bladder or piston accumulators. These so-called hydropneumatic accumulators have a gas-filled chamber that is separated from the hydraulic space by a membrane or a piston. If the hydraulic pressure increases, the compression of the gas stores the energy. Hydropneumatic accumulators are characterized by a relatively high oil volume uptake, but due to the porous die-cast aluminum they cannot be integrated into a valve plate, as this leads to tightness problems.

Hydraulic pulse accumulators are also known. A hydraulic pulse accumulator is a spring piston accumulator and is used to supply shift elements of a transmission with oil during start-stop processes. The hydraulic pulse accumulator is therefore a spring-piston accumulator that can release the oil volume taken up as required. However, due to its function, the hydraulic pulse memory is very large and cannot be integrated into the valve plate.

There is therefore a continuing need for a pressure accumulator system that can be used in a transmission control as a volume flow source to compensate for a leakage and that can be integrated into a mounting body, for example a valve plate, with regard to the space it requires. Furthermore, assembly has so far been expensive and complicated, so that assembly errors can lead to a malfunction of the pressure accumulator system.

The object of the invention is therefore to improve a pressure accumulator system with regard to the existing problems.

The object is achieved according to the invention by a pressure accumulator system for hydraulic transmission control with the features of claim 1, by an adapter arrangement according to claim 8 for the pressure accumulator system, by a piston according to claim 9 for the pressure accumulator system and by a sealing arrangement according to claim 10 for the pressure accumulator system. Preferred embodiments of the invention are specified in the subclaims and the following description, which can each represent an aspect of the invention individually or in combination.

The invention thus relates to a pressure accumulator system for hydraulic transmission control, having a longitudinal axis
a housing extending coaxially to the longitudinal axis, the housing having an end face at a first housing end and a housing connecting device at a second housing end opposite the first housing end;
a spring arrangement which extends coaxially to the longitudinal axis and which is arranged with a first spring end on the end face of the housing in an abutting manner, in particular in an abutting manner in a centering seat, and which has a second spring end opposite the first spring end;
a piston which extends coaxially to the longitudinal axis and which at least partially surrounds the second spring end circumferentially with a first piston end
and on the end face, and which is arranged with a second piston end opposite the first piston end in the direction of the second housing end, and which has a circumferential groove which is arranged along the longitudinal axis between the first and the second piston end;
a sealing arrangement which is arranged circumferentially in the groove and which is arranged so as to press radially against an inner surface of the housing.

The basic idea of the invention is that a pressure accumulator system, in particular a spring accumulator, is used as a volume flow source and not just as a damping element. Furthermore, the space required for the pressure accumulator system is optimized in such a way that it can be integrated into a valve plate of the controller as an assembly body.

Due to its structural design, the pressure accumulator system fulfills high requirements in terms of tightness and dynamics and can preferably have an oil capacity of three to five milliliters. The capacity can thus be above the volume of a previously known damping element in the automotive sector with a normal volume of a damping element of less than one milliliter, but significantly below the capacity of conventional pressure accumulators. So is the accumulator for example, able to maintain the system pressure of a system with three proportional valves with a double clutch and a separating clutch for some time in order to increase the efficiency of the transmission control.

The pressure accumulator system thus comprises at least one housing, a spring arrangement, a piston, and a sealing arrangement between the piston and the inner surface of the housing. To assemble the pressure accumulator system, the spring arrangement and the piston with the sealing arrangement are assembled from one direction. The spring arrangement is in particular a compression spring. Compression springs or helical compression springs belong to the genus of coiled torsion springs, which means that they belong to the coil springs. Compression springs are, in particular, made of round or profile wire, helically wound or coiled, torsionally loaded springs that react to pressure.

Once the spring arrangement and the piston have been inserted into the housing, the parts are held in the housing by the radial pretensioning of the sealing arrangement. This simplifies the assembly of the pressure accumulator system. The preload of the spring arrangement is finally set by screwing the assembly body, in particular the valve plates. The spring arrangement is preferably only slightly pretensioned in such a way that the volume is taken up even at low pressures. The piston is supported, for example, on a sealing plate, so that it is possible to dispense with additional securing of the piston by means of a locking ring or the like.

A use of the terms coaxial, circumferential and radial relates to the longitudinal axis of the pressure accumulator system as the reference axis. Coaxial, also known as equiaxed, is the designation for matching main longitudinal axes of three-dimensional elements in geometry. A main longitudinal axis is the axis of extension in the sense of a Cartesian coordinate system, which has the greatest magnitude compared to the other two axes of extension. A Cartesian coordinate system is an orthogonal coordinate system. The textual use of the different ends refers to the opposite ends of the respective component along the longitudinal axis. The assumption here is that the components each have their main axis of extension along the longitudinal axis.

According to a preferred embodiment of the invention, it is provided that the piston at least partially, preferably completely, has a tapering along the longitudinal axis from the groove to the second piston end which is becoming smaller. The design of the piston is a special feature of the pressure accumulator system. The piston is conical from the groove onwards, which means that the use of an assembly tool can be dispensed with when assembling the sealing arrangement. On the one hand, this facilitates the bringing together of the sealing arrangement and the piston and reduces the risk of the sealing arrangement jamming in the groove of the piston. In particular, the section is not designed as a complete cone, but rather as a truncated cone, so that the outer end face of the truncated cone can be used as a contact surface.

According to a preferred embodiment of the invention it is provided that the first piston end at least partially, preferably completely, encloses the second spring end as a sleeve, the second spring end extending as far as a closed piston end face. The design as a sleeve here has a centering and radially fixing function. A sleeve is a solid, tubular container that encloses an object, in this case the second spring end. Partial enclosing can be present, for example, if the sleeve has recesses. Complete enclosing refers to a completely closed outer surface. In other words, the fact that the second spring end extends as far as a closed piston end face means that the second spring end strikes the piston end face with its end face. In this case, the piston has a circumferential surface extending beyond the piston end face, which extends along the longitudinal axis and which surrounds the second spring end as a sleeve.

According to a preferred embodiment of the invention it is provided that the sealing arrangement has two sealing rings arranged radially one above the other, namely a radially inner O-ring and a radially outer PTFE ring, the O-ring in particular preloading the PTFE ring against the inner surface of the housing . The piston seal thus comprises a PTFE ring which is pretensioned against the housing wall by an O-ring below. The use of such a sealing arrangement in a pressure accumulator system achieves an improved ratio between tightness and dynamics, since good tightness is achieved with low friction. PTFE, polytetrafluoroethylene or polytetrafluoroethene, is an unbranched, linearly structured, partially crystalline polymer made of fluorine and carbon. PTFE is very inert. Even aggressive acids such as aqua regia cannot attack PTFE. The reason is, on the one hand, the particularly strong bond between the carbon and fluorine atoms, since fluorine is the element with the strongest electronegativity. Many substances fail to break the bonds and react chemically with PTFE. Furthermore, PTFE is characterized by the compact shell Fluorine atoms, which protect the carbon strand inside, kinetically inhibited. It has therefore proven to be sensible to use PTFE as the material for the radially outer ring in order to achieve a long-term, qualitative sealing effect. Furthermore, it has been shown that PTFE offers good coefficients of friction, so that there are no disadvantages in the dynamics of the spring accumulator or the pressure accumulator system. O-rings are ring-shaped sealing elements. The name is derived from the round, O-shaped cross-section of the ring. The material of the O-ring can be selected somewhat more flexibly, for example from different types of rubber, perfluorinated rubber, FFKM or FFPM, polyethylene, PE or also polytetrafluoroethylene, PTFE.

According to a preferred embodiment of the invention it is provided that the housing is formed in one piece, preferably monolithically. In the context of the invention, one-piece means that the housing consists of one piece in such a way that it is made coherent. This can also include weld seams. In the context of the invention, monolithic means that the housing consists of one piece in such a way that it is made coherent and seamless. The housing is made in one piece, i.e. in one piece or monolithically, since it has to be integrated in the valve plate for series applications. It has been found that the one-piece construction of the housing increases the suitability and durability of the pressure accumulator system as a volume flow source of a transmission control.

According to a preferred embodiment of the invention, it is provided that an adapter arrangement which has an adapter connection device at a first adapter end which is designed to be correlated to the housing connection device. An exemplary correlating configuration of the adapter connection device and the housing connection device can be a thread arrangement, so that a screw connection is provided. However, other positive and / or non-positive connection types can also be provided. Furthermore, it is provided that the adapter arrangement is formed on a second adapter end opposite the first adapter end and correlates to an assembly body in order to connect the pressure accumulator system to the assembly body. In particular, the second piston end strikes the first adapter end with an outer end face. It has been found that a modularity enables a high variety of uses of the pressure accumulator system.

According to a preferred embodiment of the invention it is provided that the first housing end has an opening. It has been found that the opening is advantageously positioned at this point in order to apply pressure to the pressure accumulator system. The opening is preferably arranged on the end face of the housing in such a way that a projection cross-section of the opening, displaced along the longitudinal axis, coincides with a projection cross-section of the, in particular, essentially hollow-cylindrical spring arrangement. The pressurization thus takes place in a free space and not directly on a mechanical component or on the spring arrangement. For this purpose, the opening is arranged in particular coaxially to the longitudinal axis, since the spring arrangement is also arranged coaxially to the longitudinal axis.

In particular, the opening extends into a centering receptacle. The optional centering receptacle serves to center the spring arrangement or the first spring end and is arranged in the first housing end and extends up to the end face of the housing.

The invention further relates to an adapter arrangement for a pressure accumulator system according to at least one of the preceding features, characterized the adapter arrangement according to at least one of the preceding features.

The invention further relates to a piston for a pressure accumulator system according to at least one of the preceding features, characterized the piston according to at least one of the preceding features.

The invention further relates to a sealing arrangement for a pressure accumulator system according to at least one of the preceding features, characterized the sealing arrangement according to at least one of the preceding features.

• 1: ein Druckspeichersystem als Volumenstromquelle einer Getriebesteuerung in einer perspektivischen Darstellung gemäß einer bevorzugten Ausführungsform der Erfindung;
• 2: das Druckspeichersystem als Volumenstromquelle einer Getriebesteuerung nach 1 in einer Schnittdarstellung;
• 3: das Druckspeichersystem nach den 1 und 2 in einer Schnittdarstellung; und
• 4: das Druckspeichersystem nach den 1 bis 3 in einer Explosionsdarstellung.

In the following, the invention is explained by way of example with reference to the attached drawings using preferred exemplary embodiments, wherein the features presented below can represent an aspect of the invention both individually and in combination. Show it:

• 1 : a pressure accumulator system as a volume flow source of a transmission control in a perspective illustration according to a preferred embodiment of the invention;
• 2 : the pressure accumulator system as a volume flow source of a transmission control according to 1 in a sectional view;
• 3 : the accumulator system according to the 1 and 2 in a sectional view; and
• 4th : the accumulator system according to the 1 until 3 in an exploded view.

the 1 until 4th show a common embodiment of a pressure accumulator system 10 for hydraulic transmission control.

The pressure storage system 10 includes a longitudinal axis L. and still a case 12th , which is coaxial with the longitudinal axis L. extends, the housing 12th at a first end of the housing 14th an end face 16 and at one of the first end of the housing 14th opposite, second housing end 18th a housing connector 20th having;
a spring assembly 22nd that are coaxial with the longitudinal axis L. extends and with a first spring end 24 on the face 16 of the housing 12th counter-bearing, in particular circumferentially from a centering mount 60 of the housing 12th enclosed, is arranged, and the one the first spring end 24 opposite, second spring end 26th having;
a piston 28 which is coaxial with the longitudinal axis L. extends, and with a first piston end 30th the second end of the spring 26th Circumferentially at least partially encloses and frontally abutted, and the one with the first piston end 30th opposite, second piston end 32 towards the second end of the housing 18th is arranged, and the circumferentially a groove 34 having along the longitudinal axis L. between the first and second piston ends 30th , 32 is arranged;
a sealing arrangement 36 that are circumferentially in the groove 34 is arranged and which is radially against an inner surface 38 of the housing 12th is arranged pressing.

The spring arrangement 22nd is in particular a compression spring, which is shown in full hatching for illustrative reasons only.

Especially in the 2 , 3 and 4th is shown that the piston 28 at least partially, preferably completely, from the groove 34 to the second end of the piston 32 becoming smaller a taper 40 having.

Especially in the 2 and 3 it is shown that the first piston end 30th the second end of the spring 26th at least partially, preferably completely, as a sleeve 42 encloses, with the second end of the spring 26th up to a closed piston face 44 extends.

Especially in the 3 is shown that the sealing arrangement 36 has two sealing rings arranged radially one above the other, namely a radially inner O-ring 36a and a radially outer PTFE ring 36b , in particular the O-ring 36a the PTFE ring 36b against the inner surface 38 of the housing 12th pretensioned.

In all figures of the exemplary embodiment it is shown that the housing 12th is formed in one piece, preferably monolithically.

According to 2 of the exemplary embodiment is shown that the pressure accumulator system 10 an adapter assembly 46 includes that at a first adapter end 48 an adapter connector 50 has, which correlate to the housing connecting device 20th is formed, and at one of the first adapter end 48 opposite, second adapter end 52 correlating to a mounting body 54 is designed to the pressure storage system 10 with the assembly body 54 to connect, in particular the second piston end 32 with an outer face 56 at the first end of the adapter 48 strikes.

In particular, the adapter connection devices 50 and the housing connector 20th threaded connections so that they can be connected to one another as a screw connection. This is true regardless of the other features of this embodiment.

According to the 2 and 3 of the exemplary embodiment is shown that the first housing end 14th an opening 58 has, preferably in such a way on the end face 16 of the housing 12th is arranged that there is a projection cross-section of the opening 58 shifted along the longitudinal axis L. with a projection cross-section of the, in particular, essentially hollow-cylindrical spring arrangement 22nd covers, being the opening 58 in particular coaxial to the longitudinal axis L. is arranged. It is provided in particular that the opening 58 in the centering mount 60 of the housing 12th extends.

The optional center mount 60 serves to center the spring arrangement 22nd or the first end of the spring 24 and is in the first housing end 14th arranged and extends to the end face 16 of the housing 12th .

List of reference symbols

10

Accumulator system

12th

casing

14th

first housing end

16

Face

18th

second housing end

20th

Housing connector

22nd

Spring arrangement

24

first spring end

26th

second spring end

28

piston

30th

first piston end

32

second piston end

34

Groove

36

Sealing arrangement

36a

O-ring

36b

PTFE ring

38

Inner surface of the case

40

rejuvenation

42

Sleeve

44

Piston face

46

Adapter arrangement

48

first adapter end

50

Adapter connection device

52

second adapter end

54

Assembly body

56

Outer face

58

opening

60

Centering mount

L.

Longitudinal axis

Claims (10)

Pressure accumulator system (10) for hydraulic transmission control, with a longitudinal axis (L) - A housing (12) which extends coaxially to the longitudinal axis (L), the housing (12) having an end face (16) on a first housing end (14) and a second housing end (18) opposite the first housing end (14) ) a housing connector (20); - A spring arrangement (22) which extends coaxially to the longitudinal axis (L) and which is arranged with a first spring end (24) on the end face (16) of the housing (12) in an opposing manner, and which is opposite to the first spring end (24) , has a second spring end (26); - A piston (28) which extends coaxially to the longitudinal axis (L) and which with a first piston end (30) at least partially surrounds the second spring end (26) circumferentially and abuts it at the end, and which with one of the first piston end (30) opposite, second piston end (32) is arranged in the direction of the second housing end (18), and which has a circumferential groove (34) which is arranged along the longitudinal axis (L) between the first and the second piston end (30, 32); - A sealing arrangement (36) which is arranged circumferentially in the groove (34) and which is arranged so as to press radially against an inner surface (38) of the housing (12). Accumulator system (10) according to Claim 1 , characterized in that the piston (28) at least partially, preferably completely, has a taper (40) which becomes smaller and smaller along the longitudinal axis (L) from the groove (34) to the second piston end (32). Accumulator system (10) according to Claim 1 or 2 , characterized in that the first piston end (30) at least partially, preferably completely, surrounds the second spring end (26) as a sleeve (42), the second spring end (26) extending as far as a closed piston end face (44). Pressure accumulator system (10) according to at least one of the preceding claims, characterized in that the sealing arrangement (36) has two sealing rings arranged radially one above the other, namely a radially inner O-ring (36a) and a radially outer PTFE ring (36b), in particular the O-ring (36a) biases the PTFE ring (36b) against the inner surface (38) of the housing (12). Pressure accumulator system (10) according to at least one of the preceding claims, characterized in that the housing (12) is constructed in one piece, preferably monolithically. Pressure accumulator system (10) according to at least one of the preceding claims, comprising an adapter arrangement (46) which has an adapter connection device (50) on a first adapter end (48), which is designed to be correlated to the housing connection device (20), and which on one of the first adapter end (48) opposite, second adapter end (52) is designed correlating to a mounting body (54) to connect the pressure accumulator system (10) to the mounting body (54), in particular the second piston end (32) with an outer face (56) the first adapter end (48) strikes. Pressure accumulator system (10) according to at least one of the preceding claims, characterized in that the first housing end (14) has an opening (58) which is preferably arranged on the end face (16) of the housing (12) in such a way that a projection cross section of the Opening (58) displaced along the longitudinal axis (L) with a projection cross section which in particular covers an essentially hollow-cylindrical spring arrangement (22), the opening (58) being arranged in particular coaxially to the longitudinal axis (L). Adapter arrangement (46) for a pressure accumulator system (10) according to at least one of the preceding claims, characterized in the features of the adapter arrangement (46) according to at least one of the preceding claims. Piston (28) for a pressure accumulator system (10) according to at least one of the preceding claims, characterized in the features of the piston (28) according to at least one of the preceding claims. Sealing arrangement (36) for a pressure accumulator system (10) according to at least one of the preceding claims, characterized in the features of the sealing arrangement (36) according to at least one of the preceding claims.

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