DE3305442A1 - MAIN CYLINDER FOR HYDRAULIC BRAKE SYSTEMS OF MOTOR VEHICLES - Google Patents

Description

ALFRED TEVES GMBH "■ - - P 5322 3305442

Master cylinder for hydraulic braking systems in vehicles

The invention relates to a master cylinder, in particular for hydraulic brake systems of vehicles with a Housing, the cylinder bore of which is open on one side, a piston which is arranged displaceably in the housing and with the cylinder bore forms a working space, which with a first and a second channel to the Connection with a consumer and with a follow-up container for a pressure medium in connection, one Return spring that is capable of removing the piston from the bottom part of the housing to press away against a stop and a valve for regulating the flow of the pressure valve through the second channel, the valve being formed by a piece of pipe with play in the cylinder bore is arranged to be longitudinally displaceable, which forms the working space, the Rohrstück.stirnseite a Valve ring for cooperation with an annular Carrying seat, which is arranged in a plane transverse to the master cylinder, means are provided that the With the master cylinder not actuated, move the pipe section into a position in which the valve ring on the end face moves away from its seat is at a distance so that there is an open connection between the channels, as well as means for Movement of the pipe section in the closing direction with simultaneous displacement of the piston in the direction of the Bottom part of the main cylinder too.

ALFRED TEVES GMBH

There is already a master cylinder for hydraulic brake systems of vehicles known (DE-OS-2026756) in which serving as a valve device axially displaceably mounted pipe section has two sealing rings, one of which one is provided on the end face of the pipe section and with the valve seat on a step of the master cylinder bore cooperates and the other sealing ring acts in the radial direction and engages around the pipe section. the Follow-up hole, which establishes the connection between the follow-up tank and the work area, opens in the area of the Head part of the pipe section in the radial direction into the working space, the confluence of the follow-up bore is located between the two sealing rings. The working piston of the well-known master cylinder is supported via a compression spring on the bottom part of the main cylinder, the compression spring being arranged in the working space itself is. A disadvantage of the known master cylinder is that the size of the working space must be so dimensioned must that the piston return spring can be accommodated in it, which is why a small and light construction of the known master cylinder is not possible.

The present invention seeks to provide a master cylinder of the type in question create, which is equipped with particularly durable, preferably liquid-wetted sealing arrangements is, which is also inexpensive to manufacture and whose cylinder bore can be manufactured without precision machining is. Furthermore, the frictional forces caused by seals should be low, so that in a possible

ALFRED TEVES GMBH. ■ · "P 532-2

Tandem design of the main cylinder in operation pressure differences that occur between the two hydraulic circuits remain as low as possible. In the end all necessary springs should be kept kink-proof despite the shortest construction of the entire unit and be led.

According to the invention this is achieved in that the Pipe section preferably to expand or at least partially radially outward in the area of the valve ring is cranked and the enlarged or cranked parts of the pipe section sliding on the cylinder bore issue. The channel which extends axially towards the seat with the channel opening into the working space is preferably Valve ring on the inside of the cylinder bore adjacent cranked parts and arranged with axially extending lobe-like parts-η in breakthroughs or anchored recesses in the pipe section.

In order to have sufficient space for the pipe section, the one that is immersed in the work area is Piston designed as a plunger piston, the pipe section engaging around the piston and by one in the area the end face of the piston provided collar is limited in its axial movement.

Advantageously, the pipe section is at its piston rod-side end with a radially inward direction extending bend provided in the piston starting position due to the spring acting on the pipe section in the closing direction on the collar. At a

ALFRED TEVES GMBH "P 5322

Execution of the main cylinder for two hydraulic circuits, the plunger is followed by a floating piston, which is sealingly mounted displaceably in a second section of the cylinder bore, wherein the The plunger moves in the direction of the bottom part has extending armature / with which it engages in a blind hole of the floating piston, the free End of the armature behind a nose, a projection or a locking ring on the floating piston grasps and these at pulls the return movement of the plunger into its starting position. In a preferred embodiment of the of the two-circuit master cylinder, the return spring engages around the pedal-side protruding from the cylinder housing End of the plunger and is supported on the one hand on a collar or plate arranged on the piston and on the other hand on the cylinder housing or a locking ring connected to the cylinder housing. The diameter the end of the plunger on the working space side corresponds to the diameter of the floating piston, the part of the sealing ring that is guided in a sealing manner opposite the locking ring that closes the cylinder bore on the pedal side Plunger has a slightly smaller outer diameter.

In the case of a particularly inexpensive design of a two-circuit master cylinder, the cylinder housing consists of a first, the bottom part having and the working space for the floating piston designed as a plunger receiving housing part and a continuous longitudinal bore for the pedal-operated plunger having second housing part, both housing parts firmly connected to one another, for example,

ALFRED I ¹ KVES GMBH '■ ". ■. P 5322

- 10 -

are screwed or welded and in the area of the connecting portion a seal for the implementation of the plunger into the working space for the pedal-operated plunger have in-reaching floating piston. Advantageously, the Schwirninkolben on his Bottom part facing end on a collar, behind which grips into one end of a pipe section, the other At the end of its face it carries a valve ring, which rests on the bottom part in the pressure phase and acts as a follow-up hole formed, in the axial direction opening into the working space channel closes.

The invention can be implemented in a wide variety of ways to, two of which are shown schematically in the attached drawings]), namely show:

1 shows the longitudinal section through a tandem master cylinder, how it is suitable for generating largely the same pressures in both working groups;

FIG. 2 shows the perspective illustration of the pipe section according to the tandem master cylinder according to FIGS. 1 and

3 shows the longitudinal section through a tandem master cylinder, the cylinder housing of which is constructed in two parts and which is used to generate different volumes for both hydraulic circuits.

The master cylinder according to FIG. 1 consists of a housing part 1 which has a cylinder bore 2, 44, wherein the cylinder bore is designed as a stepped bore, a plunger 3, on the one hand in the locking ring

ALFRED TEVES GMBH '' P 5 322

- 11 -

is held and guided and on the other hand via an armature 22 with its free end 24 in a blind hole 23 engages, which is provided in a floating piston 20 / which is longitudinally displaceable in the narrower cylinder bore 44 is arranged and finally a pipe piece 11 / its pedal-side bend 19 in the initial position of the plunger 3 rests against a ring 14, which in turn abuts the collar 17, which in the Area of the end face 18 is formed on the plunger 3, the pipe section 11 on its the floating piston The end facing 20 is provided with radial bends 16 is, which enclose a valve ring 12 which controls the passage of pressure medium through the channel 6, which the Connection from the follow-up tank 7 to the working space 4 is established. The working space 4 in front of the plunger 3 is connected to the consumer via a channel 5, the working space 76 in front of the floating piston 2.0 via a Channel 77 with the follow-up container 65 on the one hand and via a channel 78 with the second consumer on the other hand connected is. The longitudinal displacement of the floating piston 20 is limited by a stop 10 which is designed as a screw bolt and which is inserted into the housing part 1 is screwed in, its end protruding into the cylinder bore 21 into a corresponding recess 79 protrudes into the lateral surface of the floating piston. The largest diameter a of the plunger 3 corresponds to this Diameter b of the cylinder bore 21 for the floating piston 20, so that the plunger 3 upon displacement in the direction of the bottom part 9 of the housing part 1, can dip into the cylinder bore 21. The diameter c of the plunger 3 is dimensioned so that the stop ring 14 on the one hand on the lateral surface of the

ALFRED TEVES GMBH - P 5322

- 12 -

Plunger 3 is displaceable, on the other hand in his The end position shown in FIG. 1 abuts the collar 17 of the plunger 3. The pedal-side end of the plunger 3 is provided with a plate 26 on which the return spring 8 is supported, the main cylinder side of which End on a step of the locking ring 27 rests.

When actuating the master cylinder according to FIG. 1, the plunger 3 is first so far in the direction of the Working space moved to until the venturing 12 of the pipe section 11 or the force of the spring 15 covers the channel 6, so that a pressure builds up in the working space 4 which is propagated to the consumer via channel 5. When pressure builds up in the working space 4, the Floating piston 20 moves in the direction of actuation, so that the seal 64 passes over the channel 77 and is in the working space 76 a pressure can build up, which is propagated via the channel 78 to the consumer. If the to the Channel 78 connected consumer circuit, the floating piston 20 moves so far in the direction of the bottom part 9 until its end face 79 on the bottom part 9 and pressure can build up in the consumer circuit connected to channel 5. It's clear, dan in this case the plunger 3 a stroke movement in the direction of the bottom part 9, which is so large that the plunger 3 into the cylinder bore 44 immersed. During the return stroke movement of the plunger 3 in the direction of the pedal (not shown in more detail), the plunger is driven by the return spring 8, the plunger 3 via its armature 22 or think free end 24 pulls the floating piston 20 back into its starting position shown in Fig. 1, since the

ALFRED TEVES GMBH P 5322

thickened formed free end 24 of the armature 22 rests against a locking ring 25, so not from the The blind hole 23 of the floating piston 20 is pulled out v / can earth.

In the stepped tandem master cylinder shown in FIG. 3 the plunger 32 is sealingly held and guided in a locking ring 67, which in turn is on Housing part 33 is screwed, which in turn is welded to housing part 31. The plunger 32 is encompassed in the area of its end face 71 by a pipe section 52, the edge of which is bent radially inward or abroot 72 abuts a stop ring which in turn abuts the collar 53. The plunger 32 is supported via a compression spring 80 on the floating piston 30, which is held by an intermediate piece 81 and is performed, which in the connection section 36 between the two housing parts 31 and 33 in the cylinder bore 34, 43 is arranged. The intermediate piston 30 has a collar 39 on which a radial crotch-off of the pipe section 40 rests, the pipe section holding a venturing in the area of its bends 68, which keeps the flow the pressure medium on channel 42 is controlled. A similarly formed pipe section 52 deals with its radial Cropping 72 behind a stop ring which is slidably mounted on the plunger 32 and in the Starting position of the plunger on the collar 53 bumps. The pipe section 52 is provided with bends 55 and also has a valve ring 51 which the flow of the pressure medium in the area of the channel 45 controlled. The in the area of the intermediate piece 81

ALFRED TEVKS GMBH P 5322

- 14 -

provided seals 37, 38 separate the working spaces 29/35 hermetically from each other / with one radially extending Channel 82 in the intermediate piece 81 ensures that these seals 38, 37 are constantly from the pressure medium stay wetted.

When the tandem master cylinder shown in FIG. 3 is actuated the plunger piston 32 is moved in the direction of the bottom part 28, the spring 54 being between the locking ring 67 and the bend 55 of the pipe section is clamped, ensures that the pipe section 52 with its valve ring 51 abuts the seat 50 and the Channel 45 covers so that a pressure can build up in the working space 35, which is via the channel 46 to the Consumer breeds. As a result of the pressure build-up in the working space 35, the floating piston 30 also moves in Direction of the bottom part 28, the compression spring ensures that the pipe section 40 with his Valve ring 41 covers the channel 42, so that in the Working chamber 29 can build up a pressure which is propagated via the channel 56 to the second consumer. The compression spring 80 ensures that both valves close at the same time before pressure builds up in working space 35 will,

In the master cylinders shown in FIGS all seals 63, 64, 66 or 37, 38, 62 for sealing the pistons 3, 20 and 30, 32 are the front pressure medium wetted, so that premature wear is avoided and f.it.Ii also no significant differential pressures in the Arbeitsräuinen 4, 76 and 35, 29 due to high frictional forces can adjust in the area of the seals. To the

ALFRED TEVES GMBH "P 5322,,«

Guide of the pedal-side piston 3 or 32 is only the bottom piece 27 or 67 with a particularly short / precisely machined bore provided; the working chamber 4 or 35 in front of the plunger designed piston 3 or 36 is designed without a machined cylinder bore 2 or 34. As the pictures show, the The tandem master cylinder according to the invention is particularly easy to carry out in a stepped manner, d. i.e., perform so that the floating piston has a smaller diameter than the push rod piston or piston on the pedal side. The valve devices 6, 12, 13 or 45, 50, 51 or 42, 41, 74 are designed so that the described tandem master cylinder Also used in braking systems with anti-lock devices can find. Finally, there is an advantage of the valve devices as shown in FIGS. 1 and 3 are shown, also in that the valve devices are nachsaugefähig when in the hydraulic circuit a negative pressure is set so that if there is a lack of volume, pressure medium is sucked in on the return stroke of the piston. The return spring 8 or 48 for the plunger 3 or 32, which is arranged outside the housing, makes this possible space-saving flanging of the tandem main cylinder to a vacuum vacuum booster, with the special length / diameter ratio the return springs 8, 48 is made so that a kinking of the return springs when Working stroke is excluded with certainty.

- blank page -

Claims (1)

ALFRED TEVES GMBH 02/09/1983 Prankfurt (M) ZL / Tu / R P 5322 / 0423Q H.D. Reinartz - 50 H.Steffes - 18 Claims f 1.! Master cylinder, especially for hydraulic Brerosan "~ ^ systems of vehicles with a housing (1 or 31, 33), the cylinder bore (2, 44 or 34, 43) is open on one side, a piston (3 or . 32), which is arranged displaceably in the housing (1 or 31, 33) and with the cylinder bore (2 or 34) forms a working space (4 or 35) which has a first and a second channel (5, 6 , or 45, 46) for connection with a consumer and with a follow-up container (7 or 47) for a pressure medium in connection, a return spring (8 or 48), which is suitable for the piston (3 or 32) from To push the bottom part (9 or 28) of the housing away against a stop (10 or 49) and a valve (6, 12, 13 or 45, 50, 51,) to control the flow of the pressure medium through the second channel ( 6, or 45), - wherein the valve is formed by a pipe section (11 or 52), which with play in ALFRED TEVES GMBH - 3 Pipe section (11 or 40, 52) is anchored / wherein the second channel (6 or 42, 45) in the area of the seat (13 or 50, 74) into the working space (4 or 29, 35) joins. 3. Master cylinder according to claim 1 and 2, characterized in that the in the working space (4 or 35) plunging pistons (3 or 32) actuated by the push rod are designed as plungers is, the pipe section (11 or 52) partially engages around the piston (3 or 32), and from an im Area of the end face (18 or 71) of the piston (3 or 32) provided collar (17 or 53) in its axial movement is limited. 4. Master cylinder according to claims 1 to 3, characterized in that the pipe section (11 or 52) at its end on the push rod side with a bend (19 or 72) is provided, which in the piston starting position due to the on the pipe section (11 or 52) in Closing sense acting spring (15 or 54) on the collar (17 or 53) rests. 5. Master cylinder according to one or more of the preceding claims, characterized characterized in that the plunger (3, 32) is followed by a floating piston (20, 30), which is slidably mounted in a second section of the cylinder bore, the plunger piston (3, 30) has an armature (22, 58) which extends in the direction of the base part (9, 28) and with which it is in ALFRED TEVES GMBiI ^: ■ "■ _; ... .P 5322 33054 the cylinder bore (2 or 34) is arranged to be longitudinally displaceable, which forms the working space (4 or 35), the pipe section (11 or 52) having a valve ring (12 or 51) at the end for the interaction with an annular seat (13 or 50), which in a plane is arranged transversely to the master cylinder, wherein means (17, 53) are provided which the pipe section (11 or 52) when the master cylinder is not actuated, move it to a position in which the front Valve ring (12 or 51) is from its seat (13 or 50) at a distance so that an open There is a connection between the channels (5, 6 or 45, 46), as well as means (15 or 54) for moving the Pipe section (11 or 52) in the closing direction with simultaneous displacement of the piston (3 or 32) in the direction towards the bottom part (9 or 28) of the main cylinder, characterized in that the Pipe section (11 or 40, 52) preferably in the area of the valve ring (12 or 41, 51) at least partially radially is widened or cranked outwards and the widened or cranked parts (16 or 55, 68) slide against the cylinder bore (2 or 34, 43). 2. Master cylinder according to claim 1, characterized in that the axially to Seat (13 or 50, 74) extending towards the valve ring (12 or 41, 51) on the inside of the cylinder bore (2 or 34, 43) adjacent parts (16 or 55, 68) of the pipe section (11 or 40, 52) are arranged is, and with axially extending tab-like parts (69) in openings or recesses (70) of the ALFRKD TEVES GMBH a blind hole (23, 60) of the floating piston (20, 30) engages, the free end (24, 59) of the Armature (22, 58) behind a nose, a projection or a locking ring (25, 73) on the floating piston (20, 30) and pulls it into its starting position during the return movement of the plunger (3, 32). 6. Master cylinder according to one or more of the preceding claims, characterized characterized in that the return spring (8, 48) is the pedal-side, out of the cylinder housing (1, 33) extends around the protruding end of the plunger piston (3, 32) and on one side is arranged on a piston (3, 32) Collar or plate (26, 57) and on the other hand on the cylinder housing (1, 33) or one with the cylinder housing connected bottom piece (27, 67) is supported. 7. master cylinder according to one or more of the preceding claims characterized that the diameter (a) the end of the plunger (3) on the working space side corresponds to the diameter (b) of the floating piston (20), whereby the locking ring (27) which closes the cylinder bore (2) on the pedal side sealingly guided part of the plunger (3) has a slightly smaller outer diameter (c). 8. Master cylinder according to one or more of the preceding claims, characterized characterized in that the cylinder housing consists of a first, the bottom part (28) having and the working space (29) for the plunger designed as a ALFRED TEVES GMBH ■: P 5322 formed the housing part receiving the floating piston (30) (31) and a continuous longitudinal bore (34) for the push rod-operated plunger (32) having second housing part (33), both housing parts (31, 33) firmly connected to one another, for example screwed or welded and a seal in the area of the connecting section (36) (37, 38) for the implementation of up to the working space (35) for the pedal-operated plunger (32) have in-reaching floating piston (30). 9. Master cylinder according to one or more of the preceding claims, characterized marked that the floating piston (30) at its end facing the bottom part (28) has a collar (39) behind which one end a pipe section (40), the other end of which carries a valve ring (41) on its end face, which in the pressure phase rests on the bottom part (28) and that, designed as a follow-up bore, in the axial direction The channel (42) opening into the working space (29) is closed via an annular channel.