초록 ▼

A device for the control of a hydraulically actuated clutch (1) of an automatic transmission of a motor vehicle having a slide-valve mechanism (3) is proposed, in which a valve piston (4) can move between a first working space (7) which can be pressurized via a control line (8) with a control pressu

A device for the control of a hydraulically actuated clutch (1) of an automatic transmission of a motor vehicle having a slide-valve mechanism (3) is proposed, in which a valve piston (4) can move between a first working space (7) which can be pressurized via a control line (8) with a control pressure (p_MV) adjustable by means of an electrically operated actuator (9) and a restoring space (10) containing a restoring spring (11) that acts on the valve piston (4). The valve piston (4) is made with several piston sections (4A, 4B) that delimit a pressure space (12) which is connected via a line (13) to a clutch space (2) of the clutch (1) and which, depending on the position of the valve piston (4), has a connection to a pressure supply line (14) delivering a system pressure (p_sys) or to a pressure-relief line (15). As an emergency operation device when the actuator (9) is switched off, it is provided that during a transition to an emergency operating mode associated with the current operating mode, the pressure in the first working space (7) is maintained by means of a second piston (16), which is in communication via a second working space (18) with the clutch space (2) of the clutch (1) or that of a clutch connected in parallel therewith.

대표청구항 ▼

The invention claimed is: 1. A device for the control of a hydraulically actuated clutch (1) of an automatic transmission of a motor vehicle, with a slide-valve mechanism (3) in which a valve piston (4) can move between a first working space (7) which can be pressurized with a control pressure (p_M

The invention claimed is: 1. A device for the control of a hydraulically actuated clutch (1) of an automatic transmission of a motor vehicle, with a slide-valve mechanism (3) in which a valve piston (4) can move between a first working space (7) which can be pressurized with a control pressure (p_MV) that can be adjusted by means of an electrically operated actuator (9), and a restoring space ( 10) containing a restoring spring (11) that acts on the valve piston (4), the valve piston (4) being formed with several piston sections (4A, 4B) which delimit a pressure space ( 12) which is connected via a line (13) to a clutch space ( 2) of the clutch (1) and, depending on the position of the valve piston (4), communicates with one of a pressure supply line (14) that delivers a system pressure (p_sys) and with a pressure-relief line (15), wherein as an emergency operation device when an actuator (9) is switched off, the pressure of the first working space (7) is maintained during the transition to an emergency operating mode associated with the current operating mode by means of a second piston (16, 17) which communicates via a second working space (18, 19) with the clutch space (2) of one of the clutch (1) and a second clutch connected in parallel therewith. 2. The device according to claim 1, wherein, the second working space (18, 19) can be connected via a second line (20, 21) to said pressure-relief space (10) depending on the position of the valve piston (4). 3. The device according to claim 2, wherein the second piston (16) can move between the second working space (18) and a spring space (23) containing a restoring spring (24) that acts on the second piston (16), so that by virtue of a defined displacement, the second piston (16) opens a hydraulic connection between a line delivering a clutch pressure (p_K) to the second piston (16) and the second line (20) which, depending on the position of the valve piston (4), is connected to one of the pressure-relief space (10) and, via an OR-valve (28), to a control line (8) leading to the first working space (7). 4. The device according to claim 3, wherein the OR-valve connects the first working space (7) to one of the control pressure (p_MV) present in the control line (8), to the clutch pressure (p_K) present in the second line (20) that can be connected to the first working space (7) and to the pressure-relief space (10). 5. The device according to claim 3, wherein the OR-valve is made as one of a ball valve, a slide valve and a ball rocker. 6. The device according to claim 3, wherein in a "forward drive" operating mode the second piston (16) opens a hydraulic connection between another line (25, 25B) delivering the clutch pressure (p_K) to the second piston (16) and the second line (20) leading to one of the pressure-relief space (10) or to the first working space (7), and the second line (20) is opened via the OR-valve (28) to the first working space ( 7) and blocked off by the valve piston (4) from the pressure-relief space (10), so that when the actuator (9) which adjusts the control pressure (p_MV) is switched off, the valve piston ( 4) is held in a position corresponding to the current operating mode until the clutch pressure (p_K) supplied to the second piston (16) has become smaller than the restoring pressure acting on the valve piston (4). 7. The device according to claim 2, wherein in a "neutral" or "reverse drive" operating mode, when the actuator (9) that adjusts the control pressure (p_MV) is switched off, the valve piston (4) is pushed by the restoring spring (11) to a position corresponding to a "parking" operating mode, such that in the pressure space (12) the valve piston (4) closes off an aperture cross-section of the pressure supply line (14) which delivers the system pressure (p_sys) and opens an aperture cross-section of the pressure-relief line (15), while in the pressure-relief space (10) it opens the aperture cross-section of the line (20, 20A) that can be connected to one of the first working space (7) or to the pressure-relief space (10), and the second piston (16) adopts an abutment position in the second working space (18). 8. The device according to claim 2, wherein a line (25) delivering a clutch pressure (p_K) to the second piston (16) is branched in parallel to form a first line branch (25A) opening into the second working space (18) and a second line branch ( 25B) that can be connected to the line (20) leading to one of the first working space (7) or the pressure-relief space (10 ). 9. The device according to claim 3, wherein the second piston (16) is made with a shift groove (29), into which, after a defined displacement of the second piston (16), opens another line (25, 25B) that delivers the clutch pressure (p_K) to the second piston (16) and the line (20) that can be connected to the pressure-relief space (10) or to one of the first working space (7). 10. The device according to claim 1, wherein the first working space (7) is separated from the second working space ( 19) by the second piston (17). 11. The device according to claim 10, wherein faces of the valve piston (4) and of the second piston (17) facing the first working space (7) are the same size. 12. The device according to claim 10, wherein in a "forward drive" operating mode the second piston (17) is in contact with the valve piston (4) and covers an aperture cross-section of the control line (8), and when the actuator (9) which sets the control pressure (p_MV) is switched off, the second piston (17) maintains the valve piston (4) in a position corresponding to the current operating mode until a clutch pressure (p_K) present in the second working space (19) becomes smaller than a restoring pressure acting on the valve piston (4). 13. The device according to claim 10, wherein in the "neutral" or "reverse drive" operating mode, when the actuator (9) which sets the control pressure (p_MV) is switched off, the valve piston (4) is pushed by its restoring spring (11) to a position corresponding to the "parking" operating mode, such that in the pressure space (12) the valve piston (4) closes an aperture cross-section of the pressure supply line (14) which delivers the system pressure (p_sys) and opens an aperture cross-section of the pressure-relief line (15), while in the pressure-relief space (14) the valve piston (4) opens the aperture cross-section of the line (21) leading to the second working space (19), and in the second working space (19) the second piston (17) adopts an abutment position away from the valve piston (4). 14. The device according to claim 2, wherein the pressure-relief space is the restoring space (10). 15. The device according to claim 1, wherein the second working space (18, 19) is connected to the clutch space ( 2) of the clutch (1) via a throttle (26). 16. The device according to claim 15, wherein the throttle (26) is arranged between the clutch space (2) of the clutch (1) and a branch of the second line (20, 21) that can be connected to the pressure-relief space (10). 17. The device according to claim 15, wherein the throttle (26) has a smaller aperture cross-section than the maximum aperture cross-section of the second line (20, 21) which can be connected to the pressure-relief space (10) and can be acted upon by the clutch pressure (P_k).