DE102015204685A1 - Heated pressure cylinder for noise minimization - Google Patents

Abstract

The invention relates to a pressure cylinder (1) for generating an actuating signal for an actuating element, such as a clutch actuating bearing of a motor vehicle, with a cylinder housing (2) and a displaceable in this cylinder housing (2), with the cylinder housing (2) a fluidic pressure chamber ( 3) forming piston (4), wherein between the piston (4) and the cylinder housing (2), for sealing the pressure chamber (3) towards the environment, at least one sealing element (5a, 5b) is arranged, which the piston (4) and the cylinder housing (2) each having a contact area (6, 7) contacted, wherein a heater (8) is provided, which is arranged and configured such that it supplies at least one of the two contact areas (6, 7) in a heating state thermal energy ,

Description

The invention relates to a pressure cylinder, which is preferably designed as a master cylinder or slave cylinder, for generating a control signal for an actuating element, such as a clutch actuating bearing or a brake, a motor vehicle, with a cylinder housing and a slidably received in this cylinder housing, with the cylinder housing a fluidic Pressure chamber forming piston, between the piston and the cylinder housing, for sealing the pressure chamber to the environment, at least one sealing element is arranged, which contacts the piston and the cylinder housing, each with a contact area / touches.

Generic cylinder arrangements / impression cylinders are already known from the prior art. For example, the applicant has internal prior art, which is not yet published, but already as a patent application German Patent and Trademark Office has been filed and the file number 10 2014 215 305.0 (Filing date 4 August 2014). This discloses a pressure medium actuation cylinder which has a housing and a cylinder space formed in the housing, in which cylinder space a piston is displaceably arranged. The piston has at least one seal which bears sealingly against a wall of the cylinder chamber, wherein the housing consists of an electrically conductive antistatic plastic material.

As a result, cylinder arrangements are already known from the prior art, comprising at least one cylinder and a piston arranged therein, wherein the piston has at least one sealing element for sealing the relatively displaceable components (piston and cylinder / cylinder housing). Also, a hydraulic or pneumatic return system for a friction clutch, in particular a hydraulic clutch master cylinder or cylinder for actuating a vehicle clutch is also disclosed.

However, it has now been found that, in particular when combined with a relatively inexpensive (for example, thermoplastic) plastic housing, e.g. made of polyamide, operating noise during operation of the printing cylinder / vehicle can arise. Numerous, costly investigations have shown that the speed-dependent friction in the contact point (contact areas) between the sealing elements and the cylinder housing, which are usually relatively move and surrounded by a fluid, for example. A brake fluid, the cause of the emergence more excited Vibrations between the friction partners is. In particular, this results in the so-called "stick-slip effect", wherein it is when moving the piston relative to the cylinder housing to a jerky movement of the piston relative to the cylinder housing due to the fluctuating adhesive force between the sealing element and the cylinder housing or between the sealing element and the piston , comes. These frictional forces generated between the contact areas and the vibrations are dependent on the relative speed of the, in particular made of plastic sealing element and the housing materials. These vibrations lead to undesirable noise during operation of the vehicle.

It is therefore an object of the present invention to overcome these disadvantages resulting from the prior art and to provide a printing cylinder available that allows the quietest possible operation.

This is inventively achieved in that a heater is present / is provided, which is arranged and configured such that it supplies at least one of the two contact areas in a heating state thermal energy.

In particular, it has been found that the sealing elements can slide with increased temperatures much quieter / noiseless on the cylinder housing or on the piston along. By the entry of heat energy occurring especially at low temperatures operating noise can be avoided or minimized as much as possible.

Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

Accordingly, it is advantageous if the at least one sealing element with a first contact region is mounted so as to be non-displaceable on the piston or inserted into the piston and displaceably (relative to the cylinder housing) to the cylinder housing with a second contact region. Because especially in this arrangement of the sealing element noise generation is particularly effectively damped.

In this context, it is furthermore advantageous if the at least one sealing element at least partially /, but preferably completely, consists of a plastic material, preferably an elastomeric plastic material, more preferably an EPDM material (ie an ethylene-propylene-diene rubber) , As a result, the sealing element is designed to be particularly durable, while it reliably generates the required sealing effect.

In this context, it is also advantageous if the cylinder housing at least partially / in sections, but preferably completely, from a plastic material, preferably a thermoplastic material, more preferably a PA material (ie, a polyamide) is made / made. Especially in such cylinder housings, the heater is particularly efficient acting.

In addition, it is expedient if the heating device has at least one heating element which can be heated electrically or fluidically. As a result, the heating device is designed to be particularly compact, wherein the heating element can be integrated directly into the printing cylinder. The printing cylinder is then designed to save space.

If the heating device additionally or additionally comprises a heating element designed as a heating foil or a heating element designed as a heating wire / heating coil, the heating device is designed to be particularly compact.

Instead or in addition thereto, it is also advantageous if the heating device comprises a heating element designed as a fan (generating a hot air flow). Thus, the printing cylinder is heated particularly holistically and evenly. It is also ensured that a uniform heat distribution / temperature distribution is implemented along the entire displacement path of the piston relative to the cylinder housing.

If the heater, i. at least one heating element, at least in sections, preferably completely, attached to or in the cylinder housing, wherein the heater / the at least one heating element is cohesively, frictionally and / or positively held on the cylinder housing, the cylinder housing is heated particularly effectively.

It is also useful in this context if the heating device is at least partially attached (i.e., with at least one heating element) on an outer circumferential side of the cylinder housing or embedded in the basic material of the cylinder housing. In particular, in the embedded variant of the heating device / of the at least one heating element in the base material of the cylinder housing, it is then further advantageous if the heating device / the at least one heating element is injected / encapsulated. As a result, the heating device is even more compact attachable to or in the cylinder housing.

Alternatively or additionally, it is also advantageous if the heating device is attached to at least one heating element in sections on or in the piston, wherein the heater / the at least one heating element is then again preferably cohesively, positively and / or positively held in the piston. This makes it possible to supply the heat energy to the piston.

The heating device is advantageously designed such that it the contact areas of the at least one sealing element and the cylinder housing to a temperature between 70 ° C and 100 ° C, more preferably to a temperature between 75 ° C and 95 ° C, more preferably to a temperature between 78 ° C and 90 ° C, more preferably heated to a temperature above 80 ° C / between 80 ° C and 90 ° C. As a result, a particularly quiet operation of the printing cylinder is realized.

In other words, it is thus provided according to the invention to heat the cylinder housing. This heating is particularly effective on donor or slave cylinders that incorporate EPDM seals that seal the moving piston to the cylinder housing (preferably PA). Due to the material pairing EPDM-PA thus far resulting noise is inventively avoided. By attaching heating elements, such as e.g. Heating foils, etc., the cylinder housing should be heated to at least 80 °, preferably over 80 °, whereby the vibration behavior between the friction partners (sealing elements / seal and housing / cylinder housing) is improved and whereby the generation of noise is minimized. Thus, a donor or slave cylinder is provided which has a housing and a piston which is axially movable within the housing, wherein a seal between the piston and the housing is provided and further heating elements are mounted, namely in and / or outside of Housing to heat the housing to about / above 80 ° C to minimize the noise generated by the friction between the seal and the housing.

The invention will now be explained in more detail with reference to figures, in which context also different embodiments are shown.

Show it:

1A a schematic side view of a printing cylinder according to the invention according to a first advantageous embodiment, which side view is executed parallel to the direction of displacement of the piston and the heater has a heating element designed as a heating element,

1B an end view of the printing cylinder after 1A , where now the extension of the heating foil along the circumference of the cylinder housing is clearly visible,

2A a schematic longitudinal sectional view of the printing cylinder according to the invention according to a further advantageous, second embodiment, wherein the cylinder housing is shown in the longitudinal direction, that is cut in the direction of displacement of the piston and now the heater has a, designed as a heating wire heating element, which is embedded in the cylinder housing,

2 B again an end view of the printing cylinder after 2A .

3A 3 is a schematic longitudinal sectional view of the printing cylinder according to the invention according to a further, advantageous third exemplary embodiment, wherein the heating device now comprises a heating element which is embedded in the piston,

3B an end view of the in 3A illustrated printing cylinder, and

4 a diagram representing the ratio of the stick-slip probability (ordinate) to the relative velocity (abscissa) between the sealing element and the cylinder housing in dependence on the different temperatures.

The figures are merely schematic in nature and are for the sole purpose of understanding the invention. The same elements are provided with the same reference numerals. The different features of the various embodiments / embodiments can be freely combined with each other.

In the 2A and 2 B is an embodiment of the printing cylinder according to the invention 1 in particular, in the interior of the printing cylinder 1 can be seen. The printing cylinder 1 is designed and used in this embodiment as a master cylinder of an actuator for a clutch (namely a friction clutch) of a motor vehicle. The master cylinder / impression cylinder 1 is therefore fluidly connected via a fluidic connection with a clutch slave arranged slave cylinder of this actuator, which slave cylinder then turn on here one of the sake of clarity not further illustrated actuating element in the form of a clutch actuation bearing or disengages. The printing cylinder 1 therefore serves to generate an actuating signal / setting a specific fluidic pressure value for an actuating element in the form of a clutch actuation bearing of a motor vehicle. In further embodiments, this pressure cylinder is also directly a slave cylinder of this actuator. Also in further embodiments / embodiments, this pressure cylinder is used for other areas of the motor vehicle, namely in the form of a brake force generating cylinder for applying a fluidic control pressure for actuating an actuating element in the form of a brake shoe / a brake element.

The printing cylinder 1 has a cylinder housing 2 on, in a cylindrical sub-chamber 14 this cylinder housing 2 a piston 4 in its axial direction or in the axial direction of the sub-chamber 14 slidably mounted and guided. Together with the cylinder housing 2 , namely the inner peripheral side of the sub-chamber 14 the piston closes 4 a fluidic (here hydraulic, but alternatively also pneumatic) pressure chamber 3 together with the cylinder housing 2 one. The piston 4 that of an opening 15 here in the sub-chamber 14 protrudes into it, thus forming the pressure chamber 3 between him and the rest of the cylinder housing 2 , in particular on a side facing away from the opening of the cylinder housing 2 / the sub-chamber 14 , out. A connection 13 the pressure chamber 3 is at one of the opening 15 remote axial end portion of the cylinder housing 2 then, which is then fluidly connected to a slave cylinder.

Between the piston 4 and the cylinder housing 2 , For sealing the pressure chamber to the environment, ie in the direction of the opening 15 , is at least one sealing element 5 , in this version are two sealing elements 5a . 5b arranged / provided, which are arranged so that they the piston 4 and the cylinder housing 2 each with a contact area 6 . 7 to contact. Providing this contact is thus the pressure chamber 3 sealed to the environment. A first sealing element 5a is in a circumferentially extending first circumferential groove of the piston 4 snapped / held form-fitting. A the piston 4 radially facing region of the first sealing element 5a forms the first contact area 6 out, thus sliding against the piston 4 is appropriate. A the piston 4 remote radial side of the first sealing element 5a is then as a second contact area 7 denotes and lies on the inner peripheral side 16 of the cylinder housing 2 sealingly along the circumference. Accordingly, a second sealing element 5b similar to the piston 4 appropriate. That relative to the first sealing element 5a in the axial direction of the piston 4 offset second sealing element 5b is therefore also locked in a, circumferentially extending circumferential groove / positively held. A first contact area 6 of the second sealing element 5b again lies on the piston 4 and is non-displaceable in the circumferential groove / on the piston 4 fixed / held. A first contact area 6 , in the radial direction opposite side of the second sealing element 5b forms a second contact area 7 out, in turn, on the inner circumference side 16 of the cylinder housing 2 is applied. Thus, the second sealing element is also located 5b with his second contact area 7 sealing to the cylinder housing 2 namely on its inner peripheral side 16 , at.

The printing cylinder 1 points to one, the opening 15 facing axial side extending in the radial direction flange portion 17 on, which can be mounted here for attachment to a vehicle-fixed portion, such as on a bulkhead of the motor vehicle. Also on the side of the opening 15 is with the piston 4 one out of this opening 15 protruding connecting rod 18 non-slip connected. This connecting rod 18 connects the piston 4 continue with a pedal / foot pedal of the motor vehicle. In alternative embodiments of the printing cylinder 1 As a slave cylinder, it is implemented that, for example, the piston 4 instead is in engagement with an actuating bearing of a clutch and this actuating bearing moves to move the clutch between a disengaged and a coupled position.

In other embodiments, it is also possible that the two sealing elements 5a and 5b not in the piston 4 but instead on the inner circumference side 16 of the cylinder housing 2 are held against displacement and then with the second contact area 7 are held displaceable in the cylinder housing, whereas they are with the first contact area 6 then on a peripheral side of the piston 4 issue.

According to the invention is now a heater 8th on the impression cylinder 1 provided, which is arranged and configured in principle such that it at least one of the two contact areas 6 respectively. 7 in a heating state (the heater 8th ) Supplies heat energy. That is, the heater 8th is arranged and acts on the impression cylinder in this way 1 one that in particular the contact areas 6 respectively. 7 are heated in this heating state. This heating to a more precise temperature specified below, it is possible a particularly silent displacement of the piston 4 relative to the cylinder housing 2 implement.

As in connection with 4 it can be seen, is the heater 8th provided, these contact areas 6 . 7 to an optimum temperature, which is at least 70 ° C, namely above 80 ° C, heat. In the 4 on the abscissa is the given relative velocity between the piston 4 and the cylinder housing / subchamber 14 when operating the printing cylinder 1 whereas a "stick-slip factor" is plotted on the ordinate, indicating the likelihood or inclination to produce an unwanted, due to the jerky movement of the piston 4 relative to the cylinder housing 2 reflects generated noise. The different curves have each been recorded at different temperatures in the experiment. Here it is clear that with increasing relative speed at temperatures below 70 ° C, for example at 60 ° C, at 40 ° C or the tendency for a noise generation (ie the stick-slip factor) is relatively high. In addition, the stick-slip factor also increases with increasing relative speed between pistons 4 and cylinder housing 2 considered over the entire course too. In the curve at 80 ° C, however, it is noticeable that the stick-slip factor remains almost zero even at high relative speeds, but always very low. The heater 8th is thus designed so that they are the contact areas 6 . 7 during operation of the printing cylinder 1 ie when moving the piston 4 relative to the cylinder housing 2 heated to a temperature above 70 °, namely above 80 ° C. As a result, according to the invention, the tendency to form noise during operation of the printing cylinder 1 reduced.

In the embodiment of the 2A and 2 B has this heater 8th as a second heating element 9b trained heating element 9 on, the farther than heating wire 11 is designed. This second heating element 9a is thus electrically, ie by supplying / applying an electrical energy, heated. The heating wire 11 / the second heating element 9b is in the cylinder housing 2 , in which the cylindrical sub-chamber 14 embedded wall. The second heating element 9b is injection molded / injection molded. The second heating element 9b forms in the first embodiment, the heater 8th and in particular acts on the inner circumference side 16 and thus passively on the first contact area 6 or on the second contact area 7 warming in the heating state, so that hereby also the sealing elements 5a . 5b or the piston 4 Passively heated with. Especially in the heating state of the heating element 9b / the heater 8th thus becomes the temperature of the cylinder housing 2 and the second contact areas 7 the two sealing elements 5a . 5b kept at a temperature above 80 ° C.

The heater 8th heats the sealing elements made of an elastomeric plastic material (namely EPDM) 5a . 5b in the heating state, however, always only so far on that the temperature at the contact areas 6 respectively. 7 not the glass transition temperature of the material / plastic material of the sealing elements 5a . 5b exceeds.

Furthermore, the cylinder housing 2 , in particular the sub-chamber 14 , from a formed thermoplastic material in the form of a polyamide (PA). The cylinder housing 2 is here completely made of this plastic material and thus also the sub-chamber 14 made of this material. The heater 8th heats the cylinder housing 2 in the heating state in turn only so far on that the temperature at the contact areas 6 respectively. 7 not the glass transition temperature of the material / plastic material of the cylinder housing 2 exceeds.

Another advantageous embodiment is also in the 1A and 1B shown, this impression cylinder 1 this embodiment according to the embodiment of the 2A and 2 B is basically acting and constructed. Only the shape of the heater 8th is formed somewhat differently in this embodiment. Because the heater 8th no longer has a second heating element 9b but a first heating element 9a on. The first heating element 9a is an electrically heatable / heatable heating foil 10 educated. While the heating wire after the 2A and 2 B non-positively and positively in the cylinder housing 2 is injected / held, is the heater 8th in the form of the first heating element 9a in this variant cohesively on the cylinder housing 2 appropriate. This is the heating foil 10 on the outer circumference side 12 the sub-chamber 14 glued to the cylinder housing. The only schematically illustrated heating foil 10 , then continue in 1B is also clearly visible, does not extend completely along the entire circumference of the sub-chamber 14 but only by a little more than 180 °, preferably by an angle between 190 ° and 300 ° along the circumference around the sub-chamber 14 around.

Another advantageous embodiment of the printing cylinder 1 is then in the 3A and 3B to recognize further, wherein this embodiment in turn, in principle, as the embodiment according to 2A and 2 B is functioning and constructed. Only the heater 8th is again slightly different in this embodiment and no longer in the cylinder housing 2 but in the piston 4 in the form of a third heating element 9c educated. This third heating element 9c , which is shown only schematically, is preferably in turn designed in the form of a heating wire, but alternatively also in the form of a heating foil ausgestaltbar. This third heating element 9c is again intended for the sealing elements 5a . 5b passively by conditioning the contact areas 6 on the piston 4 to heat, thus also the second contact area 7 to heat to the above temperature above 80 °. According to 3A . 3B is the heating element 9c in / on an outer peripheral side of the piston 4 arranged.

It should also be noted that the heater 8th also additionally or alternatively, further heating elements may have. In principle, it is also possible outside the cylinder housing 2 as in a further embodiment, to install a fan in the form of another heating element, which fan generates a stream of hot air from the outside to the cylinder housing 2 is directed and thus again passively the cylinder housing 2 including the sealing elements 5a . 5b heated. In addition, it is also possible, not only electrically driven heating elements 9 / Heatable heating elements 9 to use, but also fluidic systems. Also it is possible that the heater 8th several of the heating elements described 9a to 9c at the same time.

In other words, is thus implemented by the inventive solution, a heating of the system to at least 80 ° C. The printing cylinder 1 is here as a hydraulic pressure cylinder 1 formed, whereby a hydraulic fluid is located in the pressure chamber. Alternatively, in another embodiment, the impression cylinder is 1 but also as a pneumatic pressure cylinder 1 formed, wherein preferably then air is used as a pressure medium. By heating the system thus possible, disturbing noises are minimized or even prevented. Thereby, a positive effect with respect to the noise immission can be achieved. The basic investigations showed a clear improvement of the vibration behavior of the friction partners (sealing elements 5a . 5b and the cylinder housing 2 ) at a temperature increase, resulting in low to no noise emissions.

In particular in 4 the vibration behavior (stick-slip effect) is shown as a function of the relative speed and the temperature. It can be seen that as the temperature increases, the negative friction gradient decreases, with the result that the stick-slip factor decreases. At around 80 ° C in particular occur no excited vibrations or hardly such vibrations. Thus, no or very little disturbing noises. Heating of hydraulic cylinders 1 can be done from the outside, for example by hot air. On the other hand by applying heating elements (eg heating foils, radiators, heating wires, etc.), by gluing, snapping, plugging or encapsulation during manufacture. On the cylinder housing 2 the temperature supply can be made from the outside.

Because of the modern heating elements 9 can be made extremely small, there is hardly a disadvantage of a lack of space / a space expansion. In particular, the heating foils 9a can be deformed arbitrarily, with which all possible forms of hydraulic cylinders / cylinder housings 2 can be covered. Due to the fact that the heating elements 9 specifically on the clutch master cylinder 1 and heat only small areas, the driver and the occupants feel no increase in temperature of the adjoining in this embodiment, the clutch pedal. Likewise, the temperature can be supplied from the inside, ie from an inner side of the component. The system to be improved has a piston 4 who is in a cylinder 2 emotional. It is possible to have a heating element also in the piston 4 to place, which provides the required temperature increase.

LIST OF REFERENCE NUMBERS

1

 pressure cylinder

2

 cylinder housing

3

 pressure chamber

4

 piston

5a

 first sealing element

5b

 second sealing element

6

 first contact area

7

 second contact area

8th

 heater

9

 heating element

9a

 first heating element

9b

 second heating element

9c

 third heating element

10

 heating film

11

 heating wire

12

 Outer peripheral side

13

 connection

14

 member chamber

15

 opening

16

 Inner circumferential side

17

 flange

18

 connecting rod

19

 abscissa

20

 ordinate

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

• DE 102014215305 [0002]

Claims (10)

Impression cylinder ( 1 ) for generating an actuating signal for an actuating element, such as a clutch actuating bearing, of a motor vehicle, with a cylinder housing ( 2 ) and one in this cylinder housing ( 2 ) slidably received, with the cylinder housing ( 2 ) a fluidic pressure chamber ( 3 ) forming piston ( 4 ), between the piston ( 4 ) and the cylinder housing ( 2 ), for sealing the pressure chamber ( 3 ) towards the environment, at least one sealing element ( 5a . 5b ) is arranged, which the piston ( 4 ) and the cylinder housing ( 2 ) each having a contact area ( 6 . 7 ), characterized in that a heating device ( 8th ), which is arranged and configured in such a way that it covers at least one of the two contact regions ( 6 . 7 ) supplies heat energy in a heating state. Impression cylinder ( 1 ) according to claim 1, characterized in that the at least one sealing element ( 5a . 5b ) consists at least partially of a plastic material, preferably an elastomeric plastic material (particularly preferably EPDM). Impression cylinder ( 1 ) according to claim 1 or 2, characterized in that the cylinder housing ( 2 ) consists at least partially of a plastic material, preferably a thermoplastic plastic material (more preferably PA). Impression cylinder ( 1 ) according to one of claims 1 to 3, characterized in that the heating device ( 8th ) at least one electrically or fluidically heatable heating element ( 9 ) having. Impression cylinder ( 1 ) according to one of claims 1 to 4, characterized in that the heating device ( 8th ) as a heating foil ( 10 ) or heating wire ( 11 ) configured heating element ( 9a . 9b ). Impression cylinder ( 1 ) according to one of claims 1 to 5, characterized in that the heating device ( 8th ) is designed as a fan heating element ( 9 ). Impression cylinder ( 1 ) according to one of claims 1 to 6, characterized in that the heating device ( 8th ) at least in sections on or in the cylinder housing ( 2 ) is attached. Impression cylinder ( 1 ) according to claim 7, characterized in that the heating device ( 8th ) at least in sections on an outer peripheral side ( 12 ) of the cylinder housing ( 2 ) or in the base material of the cylinder housing ( 2 ) is embedded. Impression cylinder ( 1 ) according to one of claims 1 to 8, characterized in that the heating device ( 8th ) at least in sections on or in the piston ( 4 ) is attached. Impression cylinder ( 1 ) according to one of claims 1 to 5, characterized in that the at least one sealing element ( 5a . 5b ) with a first contact area ( 6 ) against the piston ( 4 ) and with a second contact area ( 7 ) slidably on the cylinder housing ( 2 ) is present.

Images