DE7425134U - CONTROL VALVE FOR HYDRAULIC BRAKES - Google Patents

Description

Robert Bosch GmbH, Stuttgart 'R. 2189

■ description;
... " Control valve for hydraulic brakes y

The invention relates to a control valve for hydraulic single wheel brakes with at least two outlets and one inlet in a housing.

There is a control valve known, which is suitable for both single wheel as also suitable for normal braking. With him, both brake pedals act on a common master cylinder during normal braking, while separate additional valves are provided for individual wheel braking. The problem of pressure equalization thus arises here between the two brake cylinders does not appear at all during normal braking.

The object of the invention is to design a control valve of the type mentioned as simply as possible so that it is suitable for a brake system with two master cylinders and one for normal braking Ensures pressure equalization between the two brake circuits; furthermore, it should enable delay-free and reliable pressure control.

This is achieved according to the invention in that the control valve having a second inlet that each outlet communicates directly with an inlet via a channel and the channels are connected to each other via a transverse channel that two valves with two-way two-position characteristic are arranged in the housing are and that each valve has a spool, which by the force of a spring in the direction of one of the channels from the transverse channel separating locking position and against the spring force of the pressure in one of the channels in the direction of one of the channels with the transverse channel connecting open position is loaded.

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7425134 01/22/76

In this way, the control valve has the effect that in the case of individual wheel braking each brake circuit can be operated undisturbed by the other and without delay. On the other hand, it takes care of normal braking with simultaneous actuation of both master cylinders for pressure equalization between the two brake circuits, so that an undesirable unilateral braking of the vehicle is avoided. In addition, the control valve is simple and compact and is also with robust operation hardly susceptible to failure.

Further particularly advantageous embodiments of the invention result from the subclaims, the description and the drawing.

An exemplary embodiment ... (see original description, Soite 2, last paragraph)

7425134 2101.78

The single figure shows the control valve 10 with a housing = 11, in which a first (12) and a second inlet 13 and a first (14) and a second outlet 15 are arranged. The first connections 12, 14 are through a first Channel 16, the second connections 13, 15 connected to one another by a second channel 17. In the housing 11 are two blind-hole-like slide bores 18, 19 arranged from opposite sides, each of which 'slide bore 18,19 is penetrated by one of the channels 16,17. Each slide bore 18, 19 has a spacing from the channel 16, 17 Chamber 21, 23, which are connected to one another by a transverse channel 23. Furthermore, each slide hole 18,19 is through a plug 24,25 closed to the outside and receives a piston valve 26,27, whereby two 2/2-valves 28,29 im Housing 11 are formed. Each piston valve 26,27 is by a spring 33, 34 arranged in a spring space 3.1, 32 pressed into a locking position in which it rests against the plug 24,25 and the respective connection from the channel 16,17 to Chamber 21,22 interrupts. Each piston slide 26, 27 has one acted upon by the pressure in the associated channel 16, 17 Print area 35.36. Sealing rings 37, 38 ensure a seal with respect to the spring chambers 31, 32, v / elche via bores 39, 41 are connected to one another and to the outside world.

Furthermore, a shuttle valve 42 is arranged in the housing 11. its seat connections 43,44 each with one of the channels 16, 17 are connected, while the third connection 45 leads to a control connection 46.

The first and second inlets 12, 13 are connected via lines each connected to a master cylinder 47, 48, which can be actuated individually or jointly by means of brake pedals 49, 51. In front the first and second outlet 14 »15 lead lines to each a brake cylinder 52,53. To the control connection 46, a trailer brake valve 54 is attached, which is in a hydraulic

7425134 01/22/76

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Circuit 35 is switched and the pressure in a trailer

brake line 56 proportionally regulates the steering pressure.

Both brake pedals 49,51 are through a pivotable lever 57 can be mechanically locked to one another in the usual way.

The operation of the control valve 10 is as follows:

With a single wheel braking z. B. only the brake pedal 49 actuated, for which purpose the lever 57 drawn in the locked position is unlocked beforehand. So the brake pedal remains 51 in the rest position, while pressure builds up for 47 in the master cylinder. This pressure acts through the first inlet 12 first channel 16 and the harvest outlet 14 unimpeded and thus without much delay also in the brake cylinder 52. Furthermore this pressure acts on the pressure surface 35 and pushes the piston slide 26 against the force of the spring 33 up to Stop at the iinde of the slide bore 18. The controls Piston valve 26 connects to chamber 26 and channel 23. The pressure thus building up in the chamber 22 is held by the piston valve 27, which due to the lack of pressure on its pressure surface 36 of the spring 34 in the drawn Locked position is pressed. A 0-ring takes care of this 38 for perfect sealing towards the spring chamber 32, while on the other hand the overlap of the piston valve 27 is chosen large enough to ensure a sufficient seal to the channel 17; there such Jinzelradbremsungen last only a short time anyway, the control valve 10 can nevertheless be built compactly.

The pressure effective in the brake cylinder 52 is controlled via the shuttle valve 42 old 'control pressure to the trailer brake valve 54 given. However, check valve means, which are not shown in detail and which can also be actuated by the driver, are prevented from in A corresponding trailer brake pressure is built up in the trailer brake line.

7425134 Z2.01.76

In a corresponding manner, pressure can also be applied to the brake cylinder 53 in the case of single wheel braking by actuating the brake pedal 51 while the other .Brake cylinder 52 remains depressurized.

For normal braking, the two brake pedals 49, 51 are mechanically locked to one another by the lever 57. Both brake pedals 49.51 are operated together. The pressures in the main cylinders 47, 48 act on the pressure surfaces 35, 36 of both Piston slides 26,27 and press them against the force of the springs 33,34 in their open position, since the spring chambers 31,32 are vented to the outside. The first and second channels 16, 17 are therefore connected to one another via the transverse channel 23 tied together. As a result of different forces on the brake pedals 49, 51 resulting pressure differences between the two Inlets 12,13 are thus suppressed as soon as they arise, so that the brake cylinders 52,53 work evenly. In any case, the maximum Pressure in the channels 16, 17 selected and forwarded to the trailer brake valve 54 as control pressure. Since the not closer are out of service, the trailer emergency valve is proportional to the control pressure the pressure Regulate in the trailer brake system 56 so that the entire vehicle train consisting of the tractor and trailer is braked will.

The control valve is not limited to the application shown for tractors and trailer braking systems; it is suitable works particularly well with Madrescher brake systems with two master cylinders, as here, too, in addition to normal braking single wheel braking is required.

Claims (4)

Robert Bosch GmbH, Stuttgart "" 'E. 2189 ^ Claims 1. Control valve for hydraulic single wheel brakes with at least two outlets and one inlet in a housing,
characterized in that the control valve (10) has a second inlet (13), that each outlet (14, 15) communicates directly with an inlet (12, 13) via a channel (16, 17) and the channels (16, 17) are connected to one another via a transverse channel (23) that two valves in the housing; i (28,
29) are arranged with two-way two-position characteristic and that each valve (28, 29) has a piston valve (26, 27)
has, by the force of a spring (33, 34) in the direction
one of the channels (16, 17) from the transverse channel (23) separating locking position and against the spring force of the pressure in one of the
Channels (16, 17) in the direction of one of the channels (16, 17) with the transverse channel (23) connecting the open position is loaded. 2. Control valve according to claim 1, characterized in that the piston slide (26, 27) receiving slide bores (18, 19) are arranged coaxially in the housing (11) and the spring chambers (31, 32) formed in them adjoin one another. 3. Control valve according to claim 2, characterized in that the spring chambers (31, 32) are vented to the outside and each piston slide (26, 27) has a sealing ring (37, 38) around the area between the transverse channel (23) and the spring chamber (31, 32). 2 - 7425134 219176 - 2 - R. 2189 4. Control valve according to one of claims -1 to 2, characterized in that a shuttle valve (42) is arranged in the housing (11), the ports of which facing the seats (4j5, 44), respectively
with a channel (16, 17) have connection, while an between. the seats lying third connection (45) with a control outlet (46) has connection. t ' 7425134 22.9176