DE102015209966A1 - Method for filling a hydraulic system - Google Patents

Abstract

A method of filling a hydraulic system in an assembly line (1), comprising: establishing a fill port of the hydraulic system so that it can be selectively opened and closed, opening the fill port of the hydraulic system, evacuating the hydraulic system via the fill port, so as to create vacuum in the hydraulic system filling the hydraulic system with hydraulic fluid via the filling access, and closing the filling access after filling the hydraulic system. In order to enable a high-quality filling of the hydraulic system even under difficult climatic conditions such as high humidity while maintaining a production efficiency of the production line, the filling access is closed after evacuation and before filling the hydraulic system with negative pressure hydraulic system, the hydraulic system with closed Befüllzugang in the Transporting the production line, after the transport of the hydraulic system whose filling access is opened and nachvakuiert the hydraulic system via the Befüllzugang so that in the hydraulic system, a predefined vacuum (p2) is generated, and the filling of the hydraulic system is performed after Nachevakuieren the hydraulic system.

Description

The invention relates to a method as defined in the preamble of claim 1 for filling a hydraulic system in a production line.

A method of the type mentioned is, for example DE 36 33 872 C1 known. In this method, a hydraulic brake system of a motor vehicle is filled in a production line with brake fluid as hydraulic fluid. For this purpose, an adaptation head of a filling system for evacuating (vacuum suction) and with brake fluid filling with a surge tank, which represents a Befüllzugang the hydraulic brake system coupled, so that the Befüllzugang can be selectively opened and closed. Then, the filling access of the hydraulic brake system is opened and the hydraulic brake system is evacuated via the adaptation head and the filling access, so that a predefined negative pressure is generated in the hydraulic brake system. The generation of the predefined negative pressure in the hydraulic brake system serves the purpose of drying by means of evaporation of the residual moisture from the ambient air present in the hydraulic brake system and the purpose of achieving a vacuum value desired for filling with brake fluid.

The vacuum brake system is then filled with brake fluid via the adaptation head and the fill port. After filling the hydraulic brake system, the adaptation head is disconnected again from the expansion tank and the expansion tank is closed with a suitable cover. The adaptation head of the filling system can now be coupled to the expansion tank of a hydraulic brake system of a subsequent motor vehicle.

The filling plant carries out the above-described processes in the production line (for example for series production), wherein the sub-processes of evacuation and filling should proceed automatically and without interruption. Accordingly, in each case a filling system is connected to a vehicle via the adaptation head (filling adapter) during the entire process sequence and must also automatically travel in the same speed at which the vehicle is conveyed through the production line.

This means that the adaptation head must be connected to the hydraulic brake system of the vehicle in the overall cycle without interruption, since an intermediate release would open the entire system to the ambient atmosphere and interrupt the coherent cycle. The consequence of this is that, depending on the speed of the production line, it may be necessary to use several filling plants per production line and to occupy one production cycle in the production line.

Time-determining factor in the overall process is the evacuation of the hydraulic brake system. The evacuation is subject not only to the on-board conditions such. Length and diameter of the installed brake lines, type and volume of the master cylinder and type of installed hydraulic unit. An additional influence on the necessary duration of the evacuation consists in the different depending on the location and weather saturation of the ambient air with water (humidity). Basically, the relationship applies: the higher the humidity, the longer the time necessary for the (evacuation) drying of the hydraulic brake system.

This relationship can lead to significant problems at manufacturing sites with strong seasonal variations in climatic parameters (such as monsoon areas, summer / winter temperature variations). In this case, e.g. at very high humidity to increase as evakuierdauer determined as qualitatively such that the production flow must be slowed down in a production line or alternatively by investing in another filling plant for the production line additional capacity must be created. Overall, this affects the production efficiency of the affected production line.

The invention is therefore based on the object, as defined in the preamble of claim 1 method for filling a hydraulic system in a production line so that even under difficult climatic conditions such as high humidity while maintaining a production efficiency of the production line a quality-compliant filling of the hydraulic system is possible.

This is achieved with the features in the characterizing part of claim 1. Further developments of the invention are defined in the dependent claims.

The invention provides a method for filling a hydraulic system in a production line. The method according to the invention comprises the following method steps: establishing a filling access of the hydraulic system so that it can be selectively opened and closed; Opening the filling access of the hydraulic system; Evacuating the hydraulic system via the filling access, so that negative pressure is generated in the hydraulic system; Filling the hydraulic system with hydraulic fluid via the filling access; and closing the filling access after filling the hydraulic system.

The method according to the invention is characterized in that the filling access is closed after evacuation and before the filling of the hydraulic system with the hydraulic system under negative pressure; the hydraulic system is transported with closed Befüllzugang in the production line; after the transport of the hydraulic system whose Befüllzugang is opened and the hydraulic system is nachevakuiert on the Befüllzugang, so that in the hydraulic system, a predefined vacuum is generated; and that the filling of the hydraulic system is performed after Nachevakuieren the hydraulic system.

By carrying out a first evacuation and a pre-evacuation according to the method according to the invention, the total time available for evacuating and thus drying the hydraulic system can be extended. The hydraulic system is neither exposed to the ambient atmosphere in the meantime, nor is the production line slowed down. Since the filling of the hydraulic system with the hydraulic fluid is carried out only after Nachevakuieren the hydraulic system, the pre-evacuation can be performed with a simpler system, the investment cost is much lower than that for a conventional filling system for evacuation and filling with hydraulic fluid. As a result, even under difficult climatic conditions such as high humidity while maintaining the production efficiency of the production line, a high-quality filling of the hydraulic system is made possible.

According to one embodiment of the invention, to set up the filling access of the hydraulic system, so that it can be selectively opened and closed, the filling access fluid-tight (gas and liquid-tight) connected to a self-closing valve device. To evacuate the hydraulic system, a preconfiguration plant of the production line is coupled to the valve device. The valve device is actuated by the preconfiguring device for opening the filling access of the hydraulic system, and the hydraulic system is evacuated by means of the negative pressure provided by the preconfiguring device. For transporting the hydraulic system, the preconfiguration plant is decoupled from the valve device.

In other words, after the first evacuation or pre-evacuation, the valve device remains on the hydraulic system and blocks the vacuum present therein. The valve device is designed so that both a permanent foreclosure of the Befüllzugangs the hydraulic system against the surrounding atmosphere to close the Befüllzugangs the hydraulic system and a filling of the hydraulic system while opening the Befüllzugangs the hydraulic system without further technical measures are possible.

By locking the vacuum in the hydraulic system after the pre-evacuation and during transporting results in a variable period of time in which the negative pressure in the hydraulic system is substantially maintained without the hydraulic system is connected to a plant of the production line. This period of time provides additional time for the desired evaporation of the residual moisture present in the hydraulic system.

According to a further embodiment of the invention, for Nachevakuieren and filled with hydraulic fluid filling the hydraulic system, a Endkonfigurieranlage the production line with the valve remaining on the hydraulic system valve device. The valve device is actuated by the Endkonfigurieranlage to open the Befüllzugangs of the hydraulic system, and the hydraulic system is nachevakuiert by means provided by the Endkonfigurieranlage negative pressure. Preferably, the hydraulic system is then filled with provided by the Endkonfigurieranlage hydraulic fluid.

According to another embodiment of the invention, before the evacuation of the hydraulic system, a pressurized gas provided by the preconfiguring device is introduced into the hydraulic system via the valve device and the filling access, so that a predefined overpressure is generated in the hydraulic system. The pressure in the pressurized hydraulic system is measured over a predefined pressure fall time period. After the expiration of the pressure drop period, the pressurized gas is discharged from the hydraulic system to perform the evacuation of the hydraulic system. Preferably, the evacuation of the hydraulic system is performed only when the pressure in the hydraulic system is not less than a predefined pressure drop limit after the expiration of the pressure fall time period. In other words, an overpressure test is used here to check whether the hydraulic system does not exceed a predefined pressure drop per unit of time and can thus be evaluated as pressure-tight.

According to yet another embodiment of the invention, prior to filling the hydraulic system with hydraulic fluid for a predefined pressure rise time period, the pressure in the vacuum system is measured. Preferably, the filling of the hydraulic system with hydraulic fluid is performed only if, after the expiration of the pressure rise time, the pressure in the hydraulic system is not is greater than a predefined pressure increase threshold. In other words, a vacuum leak test is used here to check whether the hydraulic system does not exceed a predefined pressure rise per unit of time and can thus be evaluated as being vacuum-tight.

According to yet another embodiment of the invention, after the hydraulic system has been filled with hydraulic fluid, the valve device is disconnected from the filling inlet of the hydraulic system. The valve device is then transported back to the preconfiguration plant in order to be connected to a filling access of a hydraulic system to be subsequently filled. In other words, the valve device is advantageously used repeatedly as a circulation part up to a wear limit.

The method is preferably used in a hydraulic brake system of a vehicle to be manufactured in the production line for filling the hydraulic brake system with brake fluid.

The invention expressly extends to such embodiments, which are not given by combinations of features of explicit back references of the claims, whereby the disclosed features of the invention - as far as is technically feasible - can be combined with each other.

In the following the invention will be described by means of a preferred embodiment and with reference to the attached figures.

1 shows a diagram of a flow of a method for filling a hydraulic system in a production line according to an embodiment of the invention.

2 shows a sectional view of one for carrying out the method of 1 used valve device.

The following is with reference to the 1 and 2 a method (hereinafter called filling method) for filling hydraulic fluid with a hydraulic system in a production line 1 described according to an embodiment of the invention.

According to the present embodiment of the invention, the hydraulic system to be filled is a hydraulic brake system (not shown in detail and not separately referred to) in the production line 1 to be manufactured vehicle 50 which is designed in particular as a motor vehicle. According to the present embodiment of the invention, the hydraulic system is thus filled with brake fluid as the hydraulic fluid.

To carry out the filling process, the vehicle is located 50 in the production line 1 in a first manufacturing section A1. In the first production section A1 of the production line 1 is a preconfiguration plant 2 arranged and configured to be parallel to the vehicle 50 and along with this along the first manufacturing section A1 is movable. The preconfiguration plant 2 is set up so that it can output a compressed gas (here in particular dried compressed air) to an adaptation head (not shown) for filling the hydraulic system, but can also provide vacuum for evacuating the hydraulic system via the adaptation head.

In a first step of the filling process, at a beginning (left boundary of the first production section A1) a filling access of the hydraulic system is set up so that it can be selectively opened and closed. In the present embodiment of the invention, the inflation port is a surge tank (not shown) of the hydraulic brake system. To set up the filling access of the hydraulic system, so that it can be selectively opened and closed, the filling access is fluid-tight (gas and liquid-tight) with a in 2 shown self-closing valve device 10 connected. For this purpose, the valve device 10 screwed onto the open expansion tank of the hydraulic brake system.

The valve device 10 is designed so that both a permanent foreclosure of the filling access of the hydraulic system against the surrounding atmosphere to close the Befüllzugangs the hydraulic system and a filling of the hydraulic system while opening the Befüllenzugangs the hydraulic system are possible without further technical measures.

In a next step, the preconfiguration plant 2 the production line 1 over to the valve device 10 matching adaptation head with the valve device 10 coupled. Either directly during coupling or subsequently by pressure control, the valve device 10 from the preconfiguration plant 2 to open the filling access of the hydraulic system. The hydraulic system has in this state at a time t0 at approximately atmospheric pressure p0.

Before evacuation of the hydraulic system, then, starting from time t0 to a time t1, the preconfiguring system is started 2 supplied compressed gas via the valve device 10 and introduced the Befüllzugang in the hydraulic system, so at least one predefined overpressure p1 is generated in the hydraulic system. The overpressure p1 is predefined, for example, at p1 = 6 bar. However, the overpressure can also be predefined to a higher pressure value of greater than 6 bar.

By means of the adaptation head of the preconfiguration plant 2 integrated sensor is then measured over a predefined pressure drop duration (from time t1 to t2) across the pressure in the pressurized hydraulic system. After the expiration of the pressure drop period, the pressurized gas is discharged from the hydraulic system (from the time t2 to a time t3) to perform the evacuation of the hydraulic system.

Before the evacuation is carried out by the Vorkonfigurieranlage 2 checked whether after the pressure drop duration of the pressure in the hydraulic system is not less than a predefined pressure drop limit. In other words, here is checked whether the hydraulic system does not exceed a predefined pressure drop per unit time and thus can be assessed as pressure-tight. The evacuation of the hydraulic system is accordingly carried out after this overpressure test only if, after the expiration of the pressure drop period (from time t1 to time t2), the pressure in the hydraulic system is not less than the pressure drop limit.

If the overpressure test has been successfully passed, ie, the pressure in the hydraulic system was not less than the pressure drop limit, then in a subsequent step, the hydraulic system is read by the preconfiguring system 2 At the adaptation head provided negative pressure via the valve device 10 and the filling access is evacuated from the time t3 to a time t4, so that a predefined negative pressure p2 is generated in the hydraulic system. The generation of the predefined negative pressure p2 in the hydraulic system serves the purpose of drying by means of evaporation of the residual moisture from the ambient air present in the hydraulic system and the purpose of achieving a desired vacuum level of better than 5 mbar for filling with hydraulic fluid. Accordingly, the negative pressure p2 is predefined, for example, to p2 ≦ 3 mbar.

By means of the adaptation head of the preconfiguration plant 2 integrated sensor, after evacuation over a predefined pressure rise time period (from time t4 to time t5), the pressure in the vacuum system is measured to perform a first vacuum leak test. This is done by the Vorkonfigurieranlage 2 Checks whether the hydraulic system does not exceed a predefined pressure increase per unit of time and thus can be rated as vacuum-tight. Subsequent steps of the filling process are accordingly carried out after this first vacuum leak test only if, after the end of the pressure increase time period, the pressure in the hydraulic system is not greater than a predefined pressure rise limit value.

When the first vacuum leak test has been successfully passed, in a subsequent step, the hydraulic pump supply inlet becomes pressurized by the valve means when the hydraulic system is under vacuum 10 closed. In addition, the Vorkonfigurieranlage 2 for a subsequent transport of the vehicle 50 and its hydraulic system from the valve device 10 decoupled, which remains at the Befüllzugang. The closing of the filling access of the hydraulic system takes place either directly when decoupling the Vorkonfigurieranlage 2 or upstream via pressure control, ie if neither overpressure nor underpressure from the Vorkonfigurieranlage 2 at the valve device 10 is applied.

The next step is the vehicle 50 with the valve device 10 closed Befüllzugang the hydraulic system in a second production section A2 of the production line 1 from the time t5 to a time t6 further manufacturing steps such as assembly steps subjected. This will be the vehicle 50 and its hydraulic system in the production line 1 to a beginning of a third production section A3 of the production line 1 (left boundary of the third manufacturing section A3) transported.

In this variably adjustable period of time Δt (time t5 to time t6), the negative pressure in the hydraulic system substantially remains. This is particularly advantageous in climatically humid regions, since there due to high humidity required to meet quality criteria such as adequate drying vacuum before the actual filling with hydraulic fluid can be achieved only by a longer Evakuierdauer the hydraulic system. This is caused by the fact that the air contained in the hydraulic system (here in the brake lines) contains a lot of water which starts to "boil" at low vapor pressure (caused by the evacuation). Due to the time interval .DELTA.t the hydraulic system under negative pressure can stabilize again and additional time can be made available for the desired evaporation of the residual moisture present in the hydraulic system.

In the third production section A3 of the production line 1 is a final configuration system 3 arranged and configured to be parallel to the vehicle 50 and along with this along the third manufacturing section A3 is movable. The final configuration system 3 is set up that way on an adaptation head (not shown) this can output a hydraulic fluid (in particular brake fluid) for filling the hydraulic system, but can also provide vacuum for Nachevakuieren the hydraulic system via the adaptation head.

The next step is the final configuration system 3 the production line 1 over her to the valve device 10 matching adaptation head with the valve device 10 coupled. Either directly during coupling or subsequently by pressure control, the valve device 10 from the final configuration system 3 to open the filling access of the hydraulic system.

By means of the adaptation head of the final configuration system 3 Integrated sensor technology measures the vacuum present in the hydraulic system. More precisely, by means of the adaptation head of the final configuration system 3 integrated sensor over a predefined pressure rise time period (from the time t6 to a time t7), the pressure in the vacuum system under pressure is measured to perform a second vacuum leak test. This is done by the Endkonfigurieranlage 3 checking whether the pressure in the hydraulic system is not greater than a predefined pressure rise limit value after expiration of the pressure increase time period. In other words, it is checked here whether the hydraulic system does not exceed a predefined pressure increase per unit of time and can thus be assessed as being vacuum-tight.

If the second vacuum leak test has been successfully completed, ie, if, after the pressure rise time has elapsed, the pressure in the hydraulic system is not greater than the predefined pressure increase limit, the final configuration facility will result 3 the Nachevakuieren the hydraulic system by. In this case, the hydraulic system by means of the Endkonfigurieranlage 3 provided negative pressure via the valve device 10 and the filling access from the time t7 to a time t8 nachevakuiert, so that in the hydraulic system, the predefined vacuum p2 (eg p2 ≤ 3 mbar) is restored.

After Nachevakuieren the hydraulic system leads the Endkonfigurieranlage 3 filling the hydraulic system with hydraulic fluid. The hydraulic system is doing via the valve device 10 and the filling access from the time t8 to a time t9 of the Endkonfigurieranlage 3 supplied hydraulic fluid filled until with the hydraulic fluid, a predefined overpressure such as in particular the overpressure p1 (p1 = 6 bar) is achieved. A tolerance of ± 0.5 bar can be allowed.

Subsequently, via the valve device 10 and the Befüllzugang from time t9 to a time t10 carried out a so-called level eye, with excess hydraulic fluid is sucked out of the reservoir of the hydraulic system again until a desired final filling level of hydraulic fluid is present in the surge tank.

At the time t10, the adaptation head of the final configuration system can then be used 3 from the valve device 10 be decoupled. Thereafter, the valve device 10 separated from the Befüllzugang the hydraulic system, ie unscrewed from the surge tank. The expansion tank is then closed with a lid provided for this, so that the filling access of the expansion tank is closed.

The now again isolated valve device 10 becomes the preconfiguration plant 2 transported back to the beginning of the first manufacturing section A1, with a Befüllzugang a subsequently to be filled hydraulic system, ie the open surge tank of a hydraulic brake system to be filled another vehicle 50 to be connected. The filling process according to the invention can now be carried out again.

The following are now with particular reference to 2 structural features of the valve device used to carry out the filling method according to the invention 10 be shown.

The valve device 10 includes a cylindrical housing 11 to which a first adaptation section 12 and a second adaptation section 15 are provided. The first adaptation section 12 is structurally similar to the shape of the cover of the expansion tank, so that the valve device 10 over the first adaptation section 12 can be screwed fluid tight on an externally threaded upper edge portion of the expansion tank. For this purpose, the first adaptation section comprises 12 an internal thread 13 and a flat gasket 14 ,

The second adaptation section 15 is shaped so that the valve device 10 over the second adaptation section 15 fluid-tight with the respective adaptation heads of the preconfiguration plant 2 and the final configuration system 3 can be coupled. A similar such adaptation head is for example in DE 197 00 436 A1 shown.

From the first adaptation section 12 off is a valve assembly 20 in the case 11 screwed. The valve arrangement 20 includes a quill 21 , which on the side of the first adaptation section 12 out of the case 11 so protrudes that it specifies the final level of hydraulic fluid. The valve arrangement 20 also includes a control cylinder 22 , a valve rod 23 , a piston guide 24 , a support piston 25 , a helical compression spring 26 , a distributor 27 , a valve stem seal 28 , two O-rings 29 . 30 and three flat gaskets 31 . 32 . 33 ,

LIST OF REFERENCE NUMBERS

1

 production line

2

 Vorkonfigurieranlage

3

 Endkonfigurieranlage

10

 valve means

11

 casing

12

 first adaptation section

13

 inner thread

14

 gasket

15

 second adaptation section

20

 valve assembly

21

 Pinole

22

 control cylinder

23

 valve rod

24

 piston guide

25

 support piston

26

 Helical compression spring

27

 distributor

28

 Valve stem seal

29

 O-ring

30

 O-ring

31

 gasket

32

 gasket

33

 gasket

50

 vehicle

A1

 first production section

A2

 second production section

A3

 third production section

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 3633872 C1 [0002]
• DE 19700436 A1 [0049]

Claims (10)

Method for filling a hydraulic system in a production line ( 1 ), comprising: establishing a fill port of the hydraulic system to selectively open and close, opening the fill port of the hydraulic system, evacuating the hydraulic system via the fill port to create negative pressure in the hydraulic system, filling the hydraulic system with hydraulic fluid via the fill port , and closing the filling access after filling the hydraulic system, characterized in that the filling access is closed after evacuation and before filling the hydraulic system with negative pressure hydraulic system, the hydraulic system with closed Befüllzugang in the production line ( 1 ) is transported, after the transport of the hydraulic system whose Befüllzugang is opened and the hydraulic system is nachevakuiert on the Befüllzugang so that in the hydraulic system, a predefined vacuum (p2) is generated, and that the filling of the hydraulic system is carried out after Nachevakuieren the hydraulic system. A method according to claim 1, wherein for establishing the filling access of the hydraulic system, so that it can be selectively opened and closed, the filling access fluid-tight with a self-closing valve device ( 10 ) is connected, wherein for evacuating the hydraulic system a Vorkonfigurieranlage ( 2 ) of the production line ( 1 ) with the valve device ( 10 ), the valve device ( 10 ) from the preconfiguration plant ( 2 ) is activated to open the Befüllzugangs the hydraulic system and the hydraulic system by means of the Vorkonfigurieranlage ( 2 ) is evacuated, and wherein for transporting the hydraulic system, the Vorkonfigurieranlage ( 2 ) of the valve device ( 10 ) is decoupled. Method according to claim 2, wherein for post-evacuation and with hydraulic fluid filling of the hydraulic system an end configuration device ( 3 ) of the production line ( 1 ) with the valve device ( 10 ), the valve device ( 10 ) from the final configuration system ( 3 ) is activated to open the filling access of the hydraulic system and the hydraulic system by means of the Endkonfigurieranlage ( 3 ) is evacuated. Method according to claim 3, wherein the hydraulic system is included in the final configuration ( 3 ) supplied hydraulic fluid is filled. Method according to claim 3 or 4, wherein prior to the evacuation of the hydraulic system, one of the preconfiguration plant ( 2 ) supplied pressurized gas via the valve device ( 10 ) and the Befüllzugang is introduced into the hydraulic system, so that in the hydraulic system, a predefined pressure (p1) is generated, over a predefined pressure drop duration (t1 to t2) across the pressure in the pressurized hydraulic system is measured, and wherein after expiration the pressure drop time period (t1 to t2), the compressed gas is discharged from the hydraulic system to perform the evacuation of the hydraulic system. A method according to claim 5, wherein the evacuation of the hydraulic system is performed only when, after the expiration of the pressure drop period (t1 to t2), the pressure in the hydraulic system is not less than a predefined pressure drop limit. Method according to one of claims 1 to 6, wherein prior to filling the hydraulic system with hydraulic fluid over a predefined pressure increase time period (t4 to t5, t6 to t7) across the pressure in the vacuum system under vacuum is measured. The method according to claim 7, wherein the filling of the hydraulic system with hydraulic fluid is performed only when, after the pressure rise period (t4 to t5, t6 to t7) has elapsed, the pressure in the hydraulic system is not greater than a predefined pressure increase threshold. Method according to one of claims 3 to 8, wherein after filling of the hydraulic system with hydraulic fluid, the valve device ( 10 ) is separated from the filling access of the hydraulic system, and wherein the valve device ( 10 ) to the preconfiguration plant ( 2 ) is transported back to be connected to a Befüllzugang a subsequently to be filled hydraulic system. Method according to one of claims 1-9, wherein the method is used in a hydraulic brake system of an on-line ( 1 ) to be manufactured ( 50 ) is applied to the brake fluid filling the hydraulic brake system.

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