Hydraulic braking system

1. An external force-supported hydraulic braking system of a wheeled vehicle, comprising:

two brake circuits each having a main brake line configured to be connected to a pressure-carrying supply line or to a pressureless return line via a brake valve, and further having a number of wheel brake lines branching from the main brake line and each leading to a wheel brake cylinder of a wheel brake, comprising a valve assembly of an ABS system which at each wheel brake has an inlet valve, with a check valve connected in parallel, arranged in the corresponding wheel brake line, and an outlet valve leading from the respective wheel brake cylinder into a return line, and comprising a valve assembly of a TCS system, by means of which a pressure line can be connected directly to the main brake lines and the return lines can be blocked,

wherein the valve assembly of the TCS system has a single TCS control valve formed as a 6/2-way magnetic switching valve configured to, in a non-actuated state, block a pressure-carrying main pressure line against two bypass lines each leading directly to a respective main brake line and connect the two return lines to a pressureless collective line, and further configured to, in the actuated state, connect the main pressure line to the two bypass lines and block the two return lines against the collective line.

2. The braking system as claimed in claim 1 , wherein the TCS control valve is configured as a slide valve with a control piston having four control grooves and guided so as to move axially in a valve bore of a valve casing,

wherein the port of the main pressure line branches inside the valve casing into two switching channels which open radially into the valve bore at two mutually spaced axial positions, and in the actuated state of the TCS control valve are each connected via two control grooves of the control piston to a respective joining channel of the bypass lines, and

wherein the port of the collective line branches inside the valve casing into two switching channels which open radially into the valve bore at two further mutually spaced axial positions, and in the non-actuated state of the TCS control valve are each connected via two further control grooves of the control piston to a respective joining channel of the return lines departing from the brake valves.

3. The braking system as claimed in claim 1 , wherein for axial pressure relief of the control piston, the TCS control valve includes two vent channels which lead inside the valve casing from the two end faces of the valve bore to a respective switching channel of the collective line.

4. The braking system as claimed in claim 1 , wherein for radial pressure relief, the control piston is provided with pressure relief grooves arranged at axial positions at which, in non-actuated or actuated state of the TCS control valve, a respective joining or switching channel opens into the valve bore outside the control grooves of the control piston.

5. The braking system as claimed in claim 1 , wherein the inlet valves and the outlet valves of the ABS system are configured as 2/2-way magnetic switching valves, and for each wheel brake cylinder are arranged axially parallel and together with the respective check valve in a valve block with a common valve casing.

6. The braking system as claimed in claim 5 , wherein the inlet valves and the outlet valves are each configured as slide valves with a control piston having a single control groove and guided so as to move axially in a valve bore of the valve casing, and

wherein the port of the output-side portion of the wheel brake line branches inside the valve casing into two switching channels which each open radially into the valve bore of the inlet valve or outlet valve respectively at two mutually spaced axial positions, and of which, in the non-actuated state of the inlet valve, the one switching channel is connected via the assigned control groove to a joining channel of the wheel brake line, and in the actuated state of the outlet valve, the other switching channel is connected via the assigned control groove to a joining channel of a return line.

7. The braking system as claimed in claim 5 , wherein for axial pressure relief of the respective control piston, the inlet valve and the outlet valve each have two vent channels which lead inside the valve casing from the two end faces of the respective valve bore to the joining channel of the return line.

8. The braking system as claimed in claim 5 wherein for radial pressure relief, the control pistons of the inlet valve and the outlet valve are each fitted with a pressure relief groove arranged at an axial position at which, in the actuated state of the inlet valved and in the non-actuated state of the outlet valve, a joining or switching channel respectively opens into the assigned valve bore outside the control groove of the respective control piston.

9. The braking system as claimed in claim 5 , wherein the check valve has a ball pressed by a valve spring against the valve seat, and

wherein that the check valve is arranged in a valve bore of the valve casing which is connected inside the valve casing on the end side to the port for the output-side portion of the wheel brake line and outside the valve seat to the port for the input-side portion of the wheel brake line.

10. The braking system as claimed in claim 1 , wherein at each output-side portion of a wheel brake line, a pressure sensor is connected which is connected via a signal line to a control unit of the ABS and TCS system.