DE2737572A1 - METHOD AND DEVICE FOR VENTILATING A HYDRAULIC SYSTEM - Google Patents

Description

Applicants : Reverse Injection Company (Proprietary) Limited Midraacor House, Booysens Road, SELBY, Transvaal Province, South Africa

Method and device for venting a hydraulic

Systems

The invention relates to a method and a device for venting a hydraulic system, which consists of a master cylinder / piston arrangement, a servo cylinder / piston arrangement and one connecting the master cylinder to the servo cylinder Line for conducting hydraulic fluid between these cylinders consists.

The method and the device are particularly used for venting the hydraulic brake systems of motor vehicles.

In this context, the term venting refers to removal

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of air or dirt from the hydraulic system "or the filling, emptying or rinsing of the system with pure, unpolluted substances, ie of substances that impair the proper functioning of the system, such as dirt, air or dp;!. _t freer Understood hydraulic fluid.

In the hydraulic brake systems of known design, there are at high points of the system, e.g. at high points Place the servo cylinder, closable ventilation openings provided. The lockability is through with thread provided vent nipples, which are screwed into sockets provided with threaded holes, around the vent openings to close.

Venting of such systems is done by opening the vent opened, the cleaning nipple unscrewed and pressurized fluid by actuating the master cylinder piston is pumped, whereby the air is displaced from the servo cylinder, after which the vent opening is screwed back in of the cleaning nipple is closed again. A disadvantage of this venting method is that a person is required to actuate the master cylinder piston in order to to pump the hydraulic fluid from the master cylinder into the servo cylinder, and that another person is required, to watch the vent and then close it when all of the air has escaped. Then must the main cylinder can be refilled with hydraulic fluid up to the nominal level. One carried out in this way

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Venting is not always completely effective because it does not always succeed in removing all of the air from the system to remove.

The invention is based on the object of providing a method and a device for venting hydraulic systems create that, or which, is more effective than the previously known methods or the previously known devices.

According to the invention, the method for venting a hydraulic System consisting of a master cylinder / piston arrangement, a servo cylinder / piston arrangement, and a master cylinder with the hydraulic line connecting the servo cylinder for guiding pressure fluid between these cylinders and out a master cylinder reservoir which is in fluid communication with the master cylinder, characterized in that pressurized fluid is withdrawn from the master cylinder reservoir and hydraulic fluid is introduced into the system of the servo cylinder, to cause hydraulic fluid to flow from the servo cylinder through the hydraulic line to the master cylinder.

The hydraulic fluid can be drawn from the reservoir of the master cylinder be withdrawn while the pressure fluid in the master cylinder reservoir is kept at a target level. From the Liquid withdrawn from the master cylinder can be reintroduced into the servo cylinder.

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The introduction of hydraulic fluid can take a certain time lanf: take place, and the process can be further characterized be that at the end of that time a suction effect the servo cylinder is exerted in such a way that a reflux is effected from the servo cylinder.

The introduction of hydraulic fluid on the servo cylinder can Be preceded by a suction effect during a short period of time on the servo cylinder. The duration of the suction can be a maximum of ten seconds. The length of time during which hydraulic fluid is introduced into the cylinder can vary. The process of initiation of pressurized fluid in the system and the process of exerting a suction can automatically turn into one cyclical sequence. The process of applying suction and the process of introducing hydraulic fluid in the servo cylinder can take place by means of separate flow paths that are in connection with the servo cylinder stand.

According to the invention, the device for carrying out the method is characterized by a pressure fluid suction device for drawing off pressure fluid from the master cylinder reservoir and through a pressure fluid supply device for supplying hydraulic fluid under pressure to the servo cylinder.

Set up the hydraulic fluid suction; ¹ , can have a tube

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sen, which one üauföffnun, '·; for immersion in the hydraulic fluid to a desired level above the bottom of the master cylinder reservoir Has. The volumetric flow rate of the hydraulic fluid suction device; can be about 1.5 to 2 liters per minute and can be that of the hydraulic fluid supply device by about 5UiJ. It can be a hydraulic fluid flow connection / ·; between the pressure fluid "; speed suction device and the pressure fluid supply device can be provided.

The device can have a valve arrangement and a valve actuator for actuating the valve arrangement in such a way that the supply of pressurized fluid under pressure to the servo cylinder is terminated and a suction effect is exerted on the servo cylinder.

The device can have a valve actuation and a pressure fluid supply device and a suction device for each of a plurality of servo cylinders, the individual Valve actuations for the various servo cylinders can be actuated separately in a sequence.

The invention also extends to a device in which the pressure fluid supply device has a reservoir for has clean pressure fluid and a pressure pump whose Sau ^ side with the reservoir for the clean hydraulic fluid is connected, in which the hydraulic fluid suction device has a reservoir for used liquid and a suction pump

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has, the pressure side of which is connected to the reservoir for the used liquid, and in which at least one electric motor is intended to drive the pumps.

The device can also have a hydraulic coupling for connecting of the hydraulic fluid supply device to the servo cylinder, the hydraulic coupling being a valve closing member which is biased into the closed position, wherein the closing member is then set up for lifting from its seat is when the hydraulic coupling engages a bleeding nipple in the servo cylinder.

The invention also extends to the combination of such a device with a bleeding nipple for a servo cylinder, wherein the bleeding nipple for engaging the hydraulic coupling and for lifting the valve closing member of Hydraulic coupling is set up by his seat.

The invention also relates to a bleeding nipple with a ventilation duct and a replaceable check valve in its ventilation duct. The bleeding nipple may have internal threads in its ventilation duct for inclusion of the check valve.

The invention finally extends to a servo cylinder in a hydraulic system, in which the servo cylinder has a connection at a high point that connects to a hydraulic line from a master cylinder

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IS

is, wherein the servo cylinder has a bleeding nipple of the above described type in a deep place.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawings. In the drawings are:

Pi·:. 1 a hydraulic flow diagram and an electrical circuit diagram a device according to the invention shown in the illustration with the hydraulic brake system of a motor vehicle connected is,

Fig. 2 is a hydraulic flow diagram of one device after another Embodiment of the invention,

FiC. 3 shows a hydraulic flow diagram of a device according to another Embodiment of the invention,

Fig. 4 is a hydraulic flow diagram of a device according to a fourth embodiment of the invention,

Figure 5 is a circuit diagram of the electrical circuitry of the device after pi £. 4,

Fig. 6 is a side view of a trolley in which the device is installed according to the invention,

Pi,··. 7 is a diagram of the instrument panel of that shown in FIG. 6 Cart,

Pig. 8 is an illustration of a venting nipple which forms part of the device according to FIG. 4,

Fif ;. 9 is a hydraulic flow diagram of a device according to one further embodiment of the invention,

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Fi, ... 1ϋ an Axial3cluiitt through a hydraulic clutch / -; with an-

oschloosenen lines, as it is used / ends in the embodiment according to Fig. 9,

Fi. \ ^V. 11 shows a section through the lines along the line XI-XI in FIG. 10,

Fig. 1 ;: an electrical circuit diagram (including cams and valves) of the embodiment according to Fig. 9,

Fi.;. 1 "is a diagram of a camshaft with some on it seated cam disks,

14 shows a timing diagram of the operational sequence of the various Parts and flow along the various flow paths through valves from the various cam discs are operated, and

15 is a schematic section through a servo cylinder / bleed nipple assembly for a disc brake, in accordance with the invention.

In Fig. 1, 10 generally designates a device with a pressure fluid supply device and a pressure fluid suction device in the pressure and suction pumps for use for venting the hydraulic brake system of a motor vehicle. 12 denotes part of the braking system of a motor vehicle. The braking system has a master cylinder / piston arrangement 14, a brake pedal 16 for actuating the piston of the assembly 14 and a master cylinder reservoir 18. if When the pedal is released, the reservoir 18 is in fluid communication with the cylinder 14. The reservoir has a Filling opening 20.

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The braking system further comprises a brake servo cylinder / piston arrangement; 22 on (for example) each of the four wheels (only one of which is shown at 24) of the 3 vehicle. Of the Ihuipt cylinder of the master cylinder / piston arrangement 14 1st with the servo cylinder of the servo cylinder / piston assembly 22 through a clutch; 25 and a hydraulic line 26 connected.

The device; 10 v / eis a cart that was driven around by hand can be. It contains a pressure fluid supply device in the form of a feed pump 28. The pump 28 is a self-priming, pressure-regulated lamellar pump with a Suction side 28.22, a pressure side 28,21 and a pressure reducing connection 28.1. The pump 28 is powered by a 12 volt electric motor 30 powered. The device also has a pressure fluid suction device in the form of a suction pump, which is a peristaltic pump 32 with a suction side 32.1 and a print page 32.2. The pump 32 is powered by a 12 volt electric motor 34 through a reduction gear ? 6 powered. The device also includes a reservoir 50 for used pressure fluid and a reservoir 40 for clean pressure fluid.

A suction line 42 sum suction of pressure fluid from the Haxiptylinder reservoir 18 and a pressure line 44 for introduction of pressure fluid in the servo cylinder 22 are also provided. Me suction pipe <": 42 consists of one piece flexible hoses 42.1, which has a suction connector at its end

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dun ^ in dor I-'orni eires halcenf ömiigen piece of rigid pipe 42.2 Has. The tube 42.2 is connected to the hose 42.1 through a stopcock 46 connected. An opening in the tube 42.2 is arranged so that it is at a certain level in the master cylinder reservoir to maintain a certain level of fluid in it.

The supply line also has a piece of flexible tubing 44.1, at the end of which a supply connection in the form of a piece of rigid tube 44.2 is provided. The rigid pipe 44.2 is connected to the flexible hose by a stopcock 48. The rigid tube 44.2 can with the servo cylinder 22 by means of a screw coupling 50 are connected. To this end the servo cylinder is provided with a nipple (see Fig. 8), which has a channel in which a non-return valve sits, which is a Allow hydraulic fluid to flow into the servo cylinder.

The suction line 42 leads to the suction side 32.1 of the peristaltic pump 3 ° -. The pressure side 32.2 of the peristaltic pump 32 is connected to a two-way valve 52 so that the pressure side of the pump 32 can be connected either to the reservoir 38 for the used liquid through the line 54 or to the reservoir 40 for clean liquid through the line 56.

The pressure side 28.21 of the pump 28 is connected to the supply connection; connected by a regulating valve 58. The valve 58 is a pressure gauge 60 connected downstream.

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At

The suction side 28.22 of the pump 28 is connected to the reservoir 40 for clean liquid via a filter 62.

The pressure reducer connection 28.1 is via a T-coupling piece connected in line 56 to reservoir 40 for clean liquid.

Each reservoir 38, 40 is provided with an overflow 64 and 66, respectively. In addition, the spent liquid reservoir 38 is provided with a drain 68 which is provided with a stopcock 70 is equipped. The reservoir 40 for clean liquid is additionally provided with a poppet valve 41, which over a silica gel filter 41.1 is connected to the atmosphere.

The apparatus 10 also includes a rechargeable 12-volt battery 72 and a battery charger 74 for charging the battery from a 220-volt Vv ^T echselstromnetz from on. The battery 72 is connected to the two motors 30, 34 via a switch 76. A voltmeter 78 is provided to indicate the condition of the battery.

In use, the hook-shaped end 42.2 of the suction line is hooked into the filling opening 20 of the main cylinder reserve of the vehicle, and the shut-off valve 46 is opened. In addition , the supply line 44.2 is connected to the servo cylinder of one of the wheels of the vehicle by means of the screw coupling 50, and the valve 48 is opened.

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The two-way valve 52 is used for feeding into the reservoir 38 ■ estelli; and the unit is then activated by switch 76 switched on, which sets pumps 30 and 34 in motion.

Pressure fluid is from the reservoir 40 for the clean Liquid by means of the pump 28 through the line 44 into the hydraulic system 12 is pumped. The hydraulic fluid that is pumped into the system in this way displaces contaminated hydraulic fluid, which already exists in the system. This contaminated pressure fluid is hereinafter referred to as used up Hydraulic fluid, and it can be contaminated with air bubbles, dirt, and other contaminants. The flow takes place through the line 26 in the direction 80 to the master cylinder and then into the master cylinder reservoir 18.

At the same time, used pressure fluid is from the master cylinder reservoir 18 through the connection 42 by means of the peristaltic pump 32 sucked off. This pressure fluid is through the two-way valve 52 and the line 54 in the reservoir 38 pumped for the used hydraulic fluid.

This process is continued for about half a minute, or until there is clear pressure medium in the master cylinder reservoir 18 appears. A little later, namely after the line 42 is free of used pressure fluid, the valve 52 in brought to such a position that it is introduced into the line 56, and thereupon pressure fluid from the master cylinder reservoir 18 is sucked off to the reservoir 40 for the

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clean hydraulic fluid .pumped through the line 56. The pumps are now allowed to run for about a minute or until no more air bubbles appear in the master cylinder reservoir 18.

The flow rate of hydraulic fluid that is pumped into the system is determined by adjusting the regulator valve 58.

After the pump has been running for about a minute or a little longer the shut-off valve 48 is closed and the coupling 44.2 is unscrewed from the servo cylinder 22. After that the others will The edges of the vehicle are treated in the same way to complete the venting of the braking system.

When venting is complete, the coupling 44.2 is unscrewed and the tube 42.2 is removed from the master cylinder reservoir taken out after valves 48 and 46 are closed have been. The tubes 42 and 44 are then stowed in the cart.

In the in Pig. 2 variant shown, the feed pump 28 is omitted, and the reservoir for the clean pressure fluid is instead brought to an elevated level in order to be removed from the to make use of static head. This gives the pressure head required to allow liquid to be introduced to effect in the hydraulic system. That can be useful

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in permanent systems, such as assembly halls. In Fig. 2 the same reference numerals are used as in Fig. 1 for the same parts.

In the variant shown in Fig. 3, the suction pump 32 is omitted, and instead the reservoir for the clean liquid is brought to a deep level, i.e. below the Master cylinder reservoir level. This can cause pressure fluid from the master cylinder reservoir by siphon action be sucked off. In Fig. 3 the same reference numerals as in Fig. 1 are used for the same parts.

In a modification, the device shown in Fig. 1 can be equipped with a solenoid-operated cross valve 82, which is shown in dashed lines in FIG. The valve is connected in the acid line 42, and also in the supply line 28.21 of the pump 28 behind the regulating valve 58, as shown in dashed lines at 84 and 86, respectively. Im de-excited State then allows the cross valve 82 to vent as described above. V / hen the valve 82 is energized, however, the line 44 is connected to the suction pump 32 and the line 42 is connected to the pressure side the feed pump 28 connected.

The valve 82 is provided to prevent the reflux of pressurized fluid from the servo cylinder for a short time after the Allow the end of a vent on each wheel. It has been found that with certain vehicle parks, air that

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is present in the servo cylinders themselves, not completely is removed through the vent by the procedure described above has been described. By reversing the flow for a short time at the end of a vent, it becomes Air removed.

The switch 76 is then replaced by a two-pole changeover switch (not shown), by means of which the lifting magnet is excited by switching the switch to one of its switching positions.

In the course of further development, the device can be equipped with jump connections 88, which are fed from the pressure pump 28 through valves 90. These connections 88 are for connection provided with jump lines for venting a hydraulic system that is not hydraulic Braking system acts.

In FIG. 4, 10.4 generally designates the hydraulic fluid line of another embodiment of a device according to the invention. It is a more sophisticated version the device shown in Figs. The same reference numbers refer to the same parts. In the following description will only refer to the differences between the embodiment of FIGS. 1 to 3 on the one hand and the embodiment 4 to 9 referenced on the other hand.

This embodiment has a pressure fluid supply

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line 44 to which a manometer 60 is connected and which has a connection 44.11 with which a collecting line 45 connected is. This has as many branch supply lines 45.1 as there are servo cylinders of a motor vehicle to be operated. Usually the number is only four. Each of the supply lines 45.1 is provided with a valve 48 and a supply pipe 44.2, so that a flow through the relevant supply line 45.1 can be determined. Each feed line 45.1 is with one Connection 45.3 is provided, with which flexible hoses 45.4 can be connected, specifically via connections 45.5. Everyone flexible Hose 45.4 also has a connection 45.6 for connection to a vent nipple 21 of a servo cylinder 22. The Servo cylinder 22 has a connection 25 to which a hydraulic line 26 is connected, which is from a master cylinder 14 is fed with a reservoir 18. The master cylinder 14 has a piston 14.1 which is connected to a pedal 16.

The connections 45.3 and 45.5 can each have built-in valves so that when connections are made both valves are lifted from their seats. This is to ensure that in the various lines The hydraulic fluid contained does not flow off when the lines are removed. In the same way do the connections 45.6 and the vent nipple 21 valves, which are lifted from their seats when a connection between a Connection 45.6 and a decontamination nipple 21 is made. In this context, see the description with reference on Figs. 9 and 11.

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as

The device also has a pressure fluid suction line 42.1 with a coupling 43 with which a flexible Suction line 42 can be connected, which has a coupling 43. 1 which is provided for connection to coupling 43. Each of the couplings 43.1 and 43 has a built-in valve. These two valves lift off their seats when connected is established between the couplings 43 and 43.1. In this context, reference is also made to the description on Pig. 9 and 11 referenced.

The suction end of the suction line 42 has a relatively stiff tube 42.2 with a longitudinal slot 42.3 in the vicinity of his End is provided. A slidable sleeve 42.4 is provided over the end of the tube 42.2. The end of the tube 42.2 is can be inserted into the reservoir 18 of the master cylinder 14. By adjusting the height of the sleeve 42.4 relative to the end of the tube 42.2 and by causing the end of the tube 42.2 to rest on the bottom of the reservoir, the pressure fluid can be maintained at a desired level 18.1 while pressure fluid enters the hydraulic system through the servo cylinder 22 is fed and while pressurized fluid from the hydraulic system through the slot 42.3 in the end of the pipe 42.4 is sucked off. The arrangement is such that pressurized fluid is sucked out of the reservoir for as long the pressure fluid completely covers the exposed part of the slot 42.3. As soon as the fluid level falls below the If the sleeve 42.4 drops, part of the slot 42.3 is exposed, and air can thus enter the suction tube 42.2,

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what a drop of the 3 levels of the hydraulic fluid below the Level 18.1 prevented. In this way, pressure fluid is now which is otherwise lost by causing the reservoir 18 to overflow, is caught and does not go lost.

The flow of pressure fluid through the supply line 44 and through the exhaust pipe 42.1 is expediently regulated by a control valve 59.

A suction filter or mud flaps 51 (or both) is installed in the suction line 42.1 to such impurities to be removed, the suction pump 32 may damage or affect their operation. The suction line 42.1 or the supply line 32.2 contains a transparent part so that the purity of the pressure fluid that flows through can be assessed. Depending on the type of liquid, the position of the valve 52 can be regulated. When the liquid is clean, the valve 52 is connected to the line 56. However, if the liquid is dirty, valve 52 is set to dispense into line 54.

In FIG. 5, 100 generally designates the electrical circuit diagram of the device according to FIG. 4. These include a suction pump motor 34 and a pressure pump motor 30, which are fed by a battery 72 through lines 106. V supplied by the battery; is indicated by the voltmeter 78. The lighting

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for voltmeter 78 is provided by light 112. The lighting for pressure gauges 60 and 75 comes from lights 114 and 116, respectively. The various parts of the circuit are powered through lines 106 from battery 72 by a two-pole changeover switch 118. When the pole 118.1 makes contact with contact 118.2, the circuit is closed. When the pole 118.3 is in contact reaches contact 118.4, relay coil 120 is energized. The coil 120 opens the contacts 122 in the energized state and prevents the battery charger 74 from being switched on while Current drains from the battery 72. The battery charger 74 is powered by lines 126 from a normal AC mains fed from. The high voltage AC circuit is protected by a fuse 128. The battery charger has an indicator light 130 to indicate when it is on. The battery charger itself consists of a transformer / rectifier unit, details of which are not shown. The output of the battery charger is through lines 132 and connected to battery 72 through fuse 134. The contacts 122 are normally closed in the non-actuated state, and they only open when coil 120 is energized.

When the battery 72 is discharged and no longer has sufficient charge to power the various motors, An emergency supply can be connected to connections 140, which are connected to the Lines 106 are connected by pole 118.1, if this

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ft?

makes contact with contact 144.1.

The electrical and hydraulic equipment and the piping are all combined in a console and built into it, from which the various work steps for venting a hydraulic system can be controlled. The battery, the battery charger, the motors for the suction and pressure pump and the suction and pressure pump itself and the associated Piping and the valves, filters and the reservoir 40 for the clean pressure fluid and the reservoir 38 for the used one Liquid are therefore all grouped together. For the sake of convenience, they are grouped together in a transport cart, which has an operation panel at its upper end. In this connection, reference is made to FIGS. 6 and 7. This consists of an upright console, indicated generally at 150. He has two wheels 152 and legs 154. He can by means of Handles 156 to be pushed around. The cart 150 has one Control panel 158 on which the various control elements are mounted.

In Fig. 7 are details of the control panel as well as the various Connection lines shown.

Details of a suitable bleeding nipple according to the invention are shown in FIG. In Fig. 8, 21 generally designates a bleeding nipple according to the invention. He has one Hexagon part 180 for applying a key, a thread

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S3

for screwing into a threaded sleeve of a servo cylinder and a seat 184 for sealing against a check valve, which is indicated generally at 186 and is screwed into a threaded hole 188. The check valve 186 has essentially the same construction as that used for pneumatic tubes and pneumatic tires. It However, there is the difference that the seal 186.1 of the check valve and the seat 186.2 of the valve from one consist of elastic material that is resistant to attack by the hydraulic fluid. The nipple continues with Thread or another suitable connection 190 is provided to connect to the coupling 45.6 of the flexible supply line 45.4 to be able to. The closing member 186.3 of the check valve 186 is lifted from its seat when the coupling 45.6 is screwed onto the thread 190 (see Pig. 10). The valve closing member 45.61 rests against the end 186.31 of the locking member 186.3, which leads to the fact that both locking members are lifted from their seats. A removable dust cap 192 screwed onto thread 190 is also provided.

To bleed the hydraulic braking system of a vehicle, the cart 150 is moved so that it is near the Vehicle is located. Thereupon four lines 45.4 are connected to the couplings 45.3 and 50 of the various wheels. There are therefore four lines 45.4 which connect the console 150 to the four wheels of the vehicle. When manufacturing

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lun ·; of connections 45.6 and 21 lift the check valves, which are built into the coupling pieces from their seats. The channels in them are connected with each other set. The flexible lines 45.4 can more or less form a permanent part of the device but at 45.5 separate from the couplings 45.3 / ground.

Thereupon the tube 42.2 is in the reservoir 18 of the master cylinder 14 plugged in. The sleeve 42.4 is brought into a certain position to ensure that when pumping pressure fluid In the system a suction takes place in a sufficient amount by the suction pump so that the level does not exceed a reasonable level in the reservoir increases, e.g. B. the level 18.1, like that in Pig. 4 is indicated. Thereupon the engines switched on for the suction and pressure pumps by closing the switch 118. This ensures that the pressure fluid is clean is printed through the supply line 44 into the manifold 45. The corresponding valve 48 is opened, and the liquid then flows into the servo cylinder 22 through the flexible hose 45.4. Hydraulic fluid in the servo cylinder 22 is thereby displaced into the reservoir 18 of the master cylinder 14. Pressure fluid is, however, sucked out of the master cylinder through the pipe 42.2, and the level of the fluid in the master cylinder does not fall below the level 18.1 because of the position of the sleeve 42.4 above the slot 42.3 in the tube 42.2.

The performance of the suction pump is higher than that of the feed pump,

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so da.3 the level of the hydraulic fluid in the master cylinder is not rises above level 18.1 and therefore does not overflow at the master cylinder. The reservoir 68 can be equipped with a sniffer valve 68.1 be provided, which in turn is connected to the atmosphere via a silica gel filter 68.2. This is to ensure that the air entering the reservoir 68 is dry and that there is no condensation of water vapor in the reservoir occurs and problems arise when filling the hydraulic pressure fluid lines.

A reservoir capacity of about 5 liters has been found to be adequate for a portable device. But when a permanent installation is considered, a reservoir 40 for clean pressure fluid can be many times this Have capacity.

While the pressure fluid in the suction line 42.1 and flows in the suction pump pressure line 32.2 is dirty, the valve 52 is in such a position that the dirty pressurized fluid through line 54 to spent fluid reservoir 38 or directly to the drain through the Line 68 is derived. However, as soon as in the transparent pipe section it can be seen that the liquid is clean, the position of the valve 52 is changed so that the clean liquid is returned through the line 56 to the reservoir 40 for the clean liquid zxi.

The servo cylinder 22 shown in Fig. 4 is in one embodiment

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3%

Shown as it is commonly used in hydraulic braking systems. In other words, the vent connection 21 is provided at the top of the cylinder. It has been found that such servo cylinders may still be small Contain air bubbles, as shown at 22.1 (see Pig. 4), even after clean hydraulic fluid has passed through the servo cylinder has flowed. Under such circumstances it has been found that the bladder 22.1 can be removed from the servo cylinder by merely flowing the pressure fluid into reverse direction is effected by the lines 45.4. This happens because the position of the four-way valve 59 is changed so that suction is applied to the joint 21 for a few seconds.

With the end of the venting of the servo cylinder 22, the corresponding Valve 48 closed, and the next valve 48 for the next servo cylinder is opened. In this way, the various servo cylinders can be vented in one sequence by placing the appropriate valves in the appropriate Sequence are operated.

In the course of further development, a more sophisticated arrangement be created in that the various valves 48 in a tappet arrangement by a cam plate or cam plates operated on a spindle, so that in different positions of the cam disk around its axis different valves 48 are closed and only one

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Valve is open at any time. In this regard, will on piss. 9 to 14 referenced.

200 generally designates another embodiment of the invention with four sets of twin lines 45.41, 45.42 which terminate in four hydraulic couplings 45.6 (see details in Pig. 10 and 11). For the purpose of identification, the couplings 45.6 are marked with A, B, C and D. A clutch is provided for each wheel of a vehicle. The twin lines are connected to two valves by coupling pieces 45.3, which are each arranged in two groups 48.1 and 48.2 . The group of valves 48.1 is connected in parallel to the pressure side 44 of the pressure pump 28. The group of valves 48.2 is connected in parallel with the suction line 42.1 of the suction pump 32.

The valve groups 48.1 and 48.2 are cam-controlled, which will be described in detail below . The flow of pressure fluid through the line 42 from the reservoir of the master cylinder is regulated by a manually operated valve 43.1 and a valve controlled by a sensor 43.2 for clean pressure fluid, and also by a cam-controlled valve 43.3. The clean hydraulic fluid sensor can be in the form of a photocell that responds to light rays of sufficient strength to allow them to pass through the hydraulic fluid.

The valve group 43.1 controls the flow of the hydraulic fluid

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through lines 1A, 2B, 30 and 4D. Controls in the same way the valve group 48.2 the suction in the lines Aa, Bb, Cc and Dd.

The electrical circuit and cams of the device are in Pig. 12 shown. The details of the cams are shown in Fig. 13, and the timing of the puncture of the various Parts is shown in FIG.

The device 200 has connections 201 for connection to a battery, for example the battery of the vehicle whose brakes are being vented. Alternatively, the device can be powered by AC connections 202 and by a switch 202.1 and a transformer 203 and a full-wave rectifier 204. The device also has a small charger 205 for small charging of a battery.

The device has a six-pole selector switch 206 with three switch positions. In Pig. 12 it is shown in the switched-off switch position. When it is in the upper position it is switched to the 'automatic' position "Au" and when it is in the lower position it is switched to the 'manual "position" Ma " Main switch 207 is open and is protected by a fuse 208. In addition to containing solenoid valves 90.1, which take over the function of valves 90 according to FIGS. 1 and 4, the circuit also contains motors 30 and 34 for the pressure and suction pumps.

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The circuit also includes a cam motor 209
on, which is controlled by a variable-speed controller 209.1 and a gearbox 210 that drives the camshaft 211 on which a number of cam disks CI, CII to CX
sit. The cam disc C1 has four cams and actuates the valve 43.3 (see also Fig. 9 _t 13 and H). The cam disk C II actuates the cycle limit switch 212, which stops the machine from running when it is set to automatic. The cam disks CHI, CV, CVII and CIX each have two cams and are closed to open the suction lines Aa, Bb, Cc, Dd
The beginning and the end of a venting process for each of the wheels WI, WII, Will and WIV (see FIGS. 9, 13 and 14) in one
Sequence set up. These cam disks operate the valve group 48.2. The cam discs CIV, CVI, CVIII and CX have
each have a cam and are set up to open the pressure lines 1A, 2B, 3C and 4D (FIGS. 9 and 14) at the same time that the suction line is open through the valve 43.3 (see FIGS. 9 and 14).

The circuit also includes a push button start switch 213. and a relay coil 214 which is arranged to keep itself energized via the lower contacts 214.1. In Fig. 12, the Contacts 214.1 shown in the unswitched position. The circuit also includes a work game end indicator in the form of a light 215.

When the selector switch is in the manual position ¹ Ma ¹ (see Fig. 12), the main switch is switched on,

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and the push button switch 213 is turned on. The relay coil is excited and remains excited via the lower contacts 214.1. At the same time, motors 30 and 34 for the Pressure and suction pumps switched on, and the two solenoid valves 90.1 are excited. The device can then be used to vent any other hydraulic system by using jump connections 88 are made use of (see Figures 1 and 4). In the manual switch position, the cam disk motor is 209 not switched on.

For automatic use, the various couplings 45.6 with the nipples 21 at A, B, C, D of the four wheels WI, WII, Will and WTV connected (see Figures 9, 10 and 11).

When the selector switch 206 is in the automatic switch position When the main switch 207 and the start switch 213 are turned on, the cam motor is turned on v / earth. In addition, the parts of the device that are switched on during 'manual' operation are also switched on put into operation. The work cycle begins by pressing the start button 213 for a few seconds to ensure that that the cam disc CII no longer actuates the work cycle limit switch 212 and that the switch 212 is in its inactivated state on position shown in FIG.

The cam shaft 211 begins to rotate, and the

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Pressure and suction pumps 28 and 32 are in a timed manner Result through the valve 43.3 and the valve groups 48.1 and 48.2 connected for the various wheels that form part of the system that is vented. The connections are made according to the timing and sequence shown in FIG.

Further details can be found in the table below.

Closed wheel wheel wheel wheel Open minded WI WII Want WIY Excited Closed A. B. C. D. Closed 1-4 1-4 1-4 1-4 Phase 1 Open minded a b C. d Closed bed acd abd ABC Closed 43.3 43.3 43.3 43.3 Open minded 1 2 3 4th Phase 2 Closed 234 134 124 123 Open minded abcd abcd abcd abcd Closed 43.3 43.3 43.3 43.3 Closed 1 2 3 4th Phase 3 234 134 124 123 abcd abcd abcd abcd 43.3 43.3 43.3 43.3

One revolution of the cam disk shaft forms a complete working cycle. At the end of the work cycle, the cam is actuated CII the cycle limit switch 212 in order to switch off the device including the relay coil 214. The contacts 214.1 return to their unactuated upper switching position, in order to switch on the work cycle indicator light 215. This indicates that the vent on a vehicle in question has ended and that the hydraulic clutch 45.6 is removed at A, B, C, D and transferred to the next vehicle for the next work

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play can be concluded.

The first short suction phase, which takes effect on the line in phase 1 for a few seconds, is used to remove dust or other dirt at the inlet of the bleeding nipple. The purpose of this is to ensure that this dust or dirt is not flushed into the hydraulic system. This is followed by phase 2, in which hydraulic fluid is introduced into the servo cylinder for a period of about a minute or more. Finally, there is another short suction phase that lasts a few seconds.

The duration of the work cycle is chosen so that with the pump performance the device can vent a hydraulic system in an appropriate manner. Purely large systems can do that Duration of work therapy can be extended by using the cam motor is slowed down by regulation 209.1.

The method for venting according to the invention can be carried out particularly successfully when the line from the servo cylinder leads to the master cylinder, is at a higher point than the point at which the pressure fluid is fed into the servo cylinder. Referring to Figure 15, there is a servo cylinder assembly 220 in accordance with the invention shown.

This arrangement has two servo cylinders 222 and 224 which are connected to one another by a duct 226. The cylinders have pistons 228 and 230 on either side of a disk 232

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809808/1040

are arranged. The hydraulic line is in accordance with common practice of the main cylinder connected to the cylinder 224 approximately at the line 224.1 and a bleeding threaded nipple provided at the end of the branch channel 226.1. According to the invention, however, the hydraulic line of the master cylinder (as in Pig. 15 shown) connected to the branch duct 226.1, and vent screws or vent nipples 21 according to the invention are on a low point in each of the cylinders 222 and 224 is provided.

According to the invention, it is better to have a vent nipple of a servo cylinder at a low point instead of at a to be provided at a high place, as has been the practice to date. According to the invention, a servo cylinder is provided, the means has to be connected to a main cylinder and is provided with a bleeding nipple at a low point, which leads into the servo cylinder, the bleeding nipple having means for connection to a hydraulic fluid supply line in order to cause hydraulic fluid to flow through the servo cylinder to the master cylinder. The servo cylinder connection that goes to the Master cylinder leads, can be arranged at a high point.

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L e r s e i t e

Claims (1)

Claims 1., 'Procedure for bleeding a hydraulic system that from a master cylinder-piston arrangement, a servo-cylinder-piston arrangement, a hydraulic line connecting the master cylinder to the servo cylinder for conveying pressure fluid between these cylinders and from a master cylinder reservoir that is in fluid communication with the main cylinder stands, characterized in that pressure fluid is drawn from the master cylinder reservoir (18) and Hydraulic fluid introduced into the system of the servo cylinder (22) is to a flow of pressure fluid from the servo cylinder (22) through the hydraulic line (26) to the master cylinder (IM) to effect. 2. The method according to claim 1, characterized in that the pressure fluid from the reservoir (18) of the master cylinder is sucked out while the pressure fluid is held in the master cylinder reservoir (18) at a target level (18.1). 3. The method according to claim 1 or 2, characterized in that the pressure fluid, which from the main cylinder (14) is sucked back into the servo cylinder (22) is initiated. M. The method according to any one of claims 1 to 3, characterized 809808/1 040 - 33 -ORIGINAL INSPECTlD in that the introduction of the pressurized liquid takes place for a certain time and that suction is applied at the servo cylinder (22) at the end of this time, so that a backflow from the servo cylinder (22) is effected. 5. The method according to any one of claims 1 to 4, characterized in that the introduction of pressure fluid takes place on the servo cylinder (22) after a suction effect on the servo cylinder (22) for a short period of time. 6. The method according to claim 4 or 5, characterized in that the period of exercise of the Suction is ten seconds or less. 7. The method according to any one of claims 4 to 6, characterized characterized in that the suction and the introduction of pressure fluid into the servo cylinder (22) by separate Flow paths (45.41, 45.42) takes place, which are connected to the servo cylinder (22). 8. The method according to any one of claims 4 to 7, characterized in that da3 introducing pressure fluid in the system and the application of suction take place in a cyclical sequence. 9. The method according to claim 8, characterized 809808/1040 ~ ³⁴ " shows that the operations are carried out automatically. 10. The method according to claim 8 or 9, characterized in that the time during the pressure fluid is introduced into the cylinder, has an adjustable duration. 11. Device for performing the method according to claim 1, characterized by hydraulic fluid suction means (32, 42.2) for drawing off pressure fluid from the master cylinder reservoir (18) and by pressure fluid supply means (28, 44) for supplying hydraulic fluid under pressure to the servo cylinder (22). 12. The device according to claim 11, characterized that the hydraulic fluid supply means a tube (42.2) with a suction opening (42.3) for immersion in have the hydraulic fluid at a target level (18.1) above the bottom of the master cylinder reservoir (18). 13. Apparatus according to claim 12, characterized that the volumetric flow rate of the hydraulic fluid suction means (32) is higher than that of the hydraulic fluid supply means (28). 14. Device according to one of claims 11 to 13, marked 809808/1040 " ³⁵ " characterized by a pressure fluid flow connection ;; (59, 45.41, 45.42) between the pressure fluid drainage devices (32) and the pressure fluid supply means (28). 15. Device according to one of claims 11 to 14, ge indicates by a valve arrangement (48.1, 48.2) and a valve actuating device (209, 211, CII-CX) for actuating the valve arrangement to interrupt the supply of pressure medium under pressure to the servo cylinder (22) and to exert suction on the servo cylinder (22). 16. The device according to claim 15, characterized that two lines (45.41, 45.42) are provided, the inner ends of which are each by means of the valve arrangement (48.1, 48.2) can be connected to the hydraulic fluid supply means (28) and to the hydraulic fluid suction means (32) and the outer ends of which, remote from the valve assembly, terminate in a single passage (45 # 6) associated with the servo cylinder (22) is connectable. 17. Apparatus according to claim 15 or 16, characterized in that the valve actuating device (209, 211, CI-CX) for shutting off the pressure fluid supply (28) and for exerting suction on the servo cylinder (22) for a short period of time immediately following can be actuated to the introduction of pressure fluid into the servo cylinder (22). - 36 809808/1040 18. Device according to one of claims 15 to 17, characterized in that the Ventilbetätir ^ ungseinrichtung (209, 211, CHI, GV, CVII, CIX) to exercise a suction effect on the servo cylinder (22) for a short period of time immediately before the introduction of pressure fluid can be actuated in the servo cylinder (22). 19. Device according to one of claims 15 to 18, characterized in that the valve actuation device: (209, 211, CI-CX) to open the valve arrangement (43.3, 48.1, 43.2) for the hydraulic fluid supply and suction in a certain sequence \ ind to close the Valve arrangement · is set up after certain times. 20. Apparatus according to claim 19, characterized that the valve actuating device has at least one rotatable cam disk for actuating the valve assembly (43.3, 48.1, 48.2). 21. Apparatus according to claim 19 or 20, characterized in that that a valve operating device (209, 211, CI-CX) and pressure fluid supply means (28) and - suction means (32) for each of several servo cylinders (22) are provided, the various valve actuation devices (CI-CX) for the various servo cylinders (22) being separate can be actuated in one pole. 22. Device according to one of claims 19 to 21, g e - 809808 / 1CU0 _ ₃₇ characterized by an electric motor (209) for driving the valve actuator (211, CI-CX). 23. Vorrichtunc according to one of claims 11 to 22, characterized in that the pressure fluid supply means a reservoir (40) for clean pressure fluid and a pressure pump (28), the suction side of which is connected to the reservoir for the clean pressure fluid that the pressure fluid suction means a reservoir (38) for used liquid and a suction pump (32), the pressure side of which with the reservoir for the used liquid is connected, and that at least one electric motor (30, 34) is provided for driving the pumps (28, 32). 24. Apparatus according to claim 22 or 23, characterized in that the motors (209, 30, 34) of a vehicle battery can be supplied with electricity. 25. Device according to one of claims 11 to 24, characterized by a mobile console (Fig. 6) with a control panel (Fig. 4). 26. Device according to one of claims 11 to 25, characterized in that a hydraulic coupling (45.6) is provided for connecting the hydraulic fluid supply means (28) to the servo cylinder (22) and the coupling a valve closing member (45.61) which is in the closed position - 38 - 809808/1040 is pressed and is set up to lift off its seat when the hydraulic coupling (45.6) is on a bleed nipple (21) engages in the servo cylinder (22). 27. Combination of the device according to claim 26 with a vent nipple for a servo cylinder, characterized in that the vent nipple (21) for Engaging the hydraulic coupling (45.6) and lifting the valve closing member (45.61) of the hydraulic coupling from his Seat is provided. 29. Vent nipple for forming part of the combination according to claim 28, characterized in that that it has a valve closing member (186.3) which is pressed into a closed position on its seat and that for lifting is set up from its seat when the hydraulic coupling (45.6) engages on the bleeding nipple (21). 30. Vent nipple with a vent channel, characterized by a replaceable check valve (186) in its ventilation duct. 31. Ventilation nipple according to claim 30, characterized in that it has an internal thread (188) in legs Ventilation channel for receiving the check valve (186) carries. 32. Vent nipple according to claim 31, characterized in that - 809808/1040 " ³⁹ " indicates that he has an external thread (190) around the
Has the outlet of the ventilation duct around and a removable dust cap (192) cooperates with this thread to close off the outlet of the ventilation duct. 33 · Ventilation nipple according to one of Claims 30 to 32, characterized in that the non-return
valve (186) has a closing member shaft (I86.31) in the outer
opening of the ventilation duct. 34. Vent nipple according to claim 33 for forming a part
the combination according to claim 27, characterized in that the hydraulic coupling (45.6) can be placed on the shaft (186.31) for lifting the closing element (I86.3) of the check valve (186) in the nipple (21) from its seat. 35 · Servo cylinder for a hydraulic system, characterized by a connection (25) at a high point for connection to one of a master cylinder
(14) leading hydraulic line (26) and through a bleed screw or a bleed nipple (21) with connecting means for connection to a pressure fluid supply (28) for allowing pressure fluid to flow through the servo cylinder (222, 224) into the master cylinder (14). 36. Servo cylinder according to claim 35, characterized by a vent nipple (21) according to one of the claims 29 to 34. 809808 / 10AO