Locking device for securing a motor vehicle component which is displaceable relative to a motor vehicle structure and which may be secured by means of the locking device within a displacement range in a respective position of rest reached by displacement, comprising: - at least one first frictional element of the locking device and - at least one second frictional element of the locking device, which is moved relative to the first frictional element upon displacement of the motor vehicle component and thereby may slide with a friction surface along a friction surface of the first frictional element under sliding friction conditions and which, in a respective position of rest of the motor vehicle component, with its friction surface bears against the friction surface of the second frictional element under static friction conditions, wherein the first and second frictional elements (1, 2; 1a, 1b, 1c, 2a, 2b; 101, 102; 101a, 101b, 101c, 102a, 102b) are braced against one another in such a way that they tend to abut on one another with their friction surfaces (10, 20; 10a, 10b, 10c, 20a, 20b; 110, 120; 110a, 110b, 110c; 120a, 120b), and at least one frictional element (2; 2a, 2b; 102; 102a, 102b) is mounted in such a way that it may be readjusted along the effective direction (R; R1, R2) of the pretensioning with respect to the other frictional element (1; 1a, 1b, 1c; 101; 101a, 101b, 101c), wherein a flowable additional medium is provided which may be brought, upon a relative movement of the frictional elements (1, 2; 1a, 1b, 1c, 2a, 2b; 101, 102; 101a, 101b, 101c, 102a, 102b), between their friction surfaces (10, 20; 10a, 10b, 10c, 20a, 20b; 110, 120; 110a, 110b, 110c, 120a, 120b), wherein the second frictional element (2; 2a, 2b; 102; 102a, 102b) is coupled to the displaceable motor vehicle component (H, S) via a coupling mechanism and the coupling mechanism comprises a shaft to which the second frictional element (2; 2a, 2b; 102; 102a, 102b) is connected so as to rotate with the shaft and which is operatively connected to the motor vehicle component (H, S), and wherein the second frictional element (2; 2a, 2b; 102; 102a, 102b) is connected to the shaft in a positive locking manner such that the second frictional element (2; 2a, 2b; 102; 102a, 102b) is mounted, with respect to the shaft, so as to rotate with the shaft and at the same time axially movably, characterized in that the friction surfaces (10, 20; 110, 120) of the frictional elements (1, 2; 101, 102) run at an acute angle or conically with respect to the effective direction (R; R1, R2) of the pre-tensioning and at least one guide channel is provided at one of the frictional elements (1, 2; 101, 102) via which the flowable additional medium may be brought between the friction surfaces (10, 20; 10a, 10b, 10c, 20a, 20b; 110, 120; 110a, 110b, 110c, 120a, 120b) associated to one another, wherein the at least one guide channel substantially extends along the effective direction of the pre-tensioning, but which thereby - in accordance with the Inclination of the friction surface (20; 120) of the frictional element (2; 102) which comprises the guide channel - are inclined to said direction (R; R1, R2). - at least one first frictional element of the locking device and - at least one second frictional element of the locking device, which is moved relative to the first frictional element upon displacement of the motor vehicle component and thereby may slide with a friction surface along a friction surface of the first frictional element under sliding friction conditions and which, in a respective position of rest of the motor vehicle component, with its friction surface bears against the friction surface of the second frictional element under static friction conditions,