Pressure control installation for hydraulically shifted automatic transmissions, especially for motor vehicles

Claim 2

A pressure control installation for hydraulically shifted automatic transmission of a machine having a line system for a pressure fluid comprising a source of pressure fluid for the line system, transmitter means for generating an electric output signal in dependence on an operating magnitude of the machine, control means connected in the line system for providing a control pressure for shifting of the transmission, said control means including electric pressure regulating means responsive to the electric output signal of said generating means for effecting the regulation of the control pressure in dependence on the operatiNg magnitude, said electric pressure regulating means including solenoid valve means having an electro-magnet and including a magnetic housing and magnetic core with an annularly shaped gap therebetween, and a bell-shaped armature arranged for movement of its cylindrical rim within said annularly shaped gap such that the range of movement of said armature is effected under an essentially constant magnetic force produced by said electromagnet and said electric output signal, said control means including a further pressure regulating means, said electric pressure regulating means applying a pilot control pressure to said further pressure regulating means, and at least one working pressure supplied by said pressure source being applied to said further pressure regulating means in opposition to the pilot control pressure, said further pressure regulating means being responsive to the applied pressures for regulating the control pressure for effecting the shifting of the transmission, said further pressure regulating means actuated by the electrically controlled pilot control pressure including a first slide valve means acted upon by said control pressure and a second slide valve means which is acted upon by a working pressure supplied by said pressure source and controlled by said further pressure regulating means in a direction opposite to said pilot control pressure, a spring guide means having a pressure element displaceable relative thereto in one direction and provided with spring abutment means as well as three spring means interconnected between said first and second slide valve means, the weakest one of said spring means being arranged between the first slide valve means and the spring guide means, the second strongest spring means being arranged with prestress between an abutment at the spring guide means and the spring abutment means whereas the third spring means having a strength intermediate the first and second spring means is supported, on the one hand, at the second slide valve means and, on the other, at the spring abutment means forcing the same against a fixed abutment.

Claim 3

A pressure control installation according to claim 1, wherein said further pressure regulating means includes means responsive to the electrically controlled pilot control pressure for producing signals for at least one of two output pressures consisting of an idling pressure signal and a full-load pressure signal.

Claim 4

A pressure control installation according to claim 1, characterized in that the machine is a motor vehicle and the operating magnitude is the position of an accelerator lever.

Claim 5

A pressure control installation according to claim 1, characterized in that said magnetic valve means is opened by a pilot control pressure of said hydraulic medium.

Claim 6

A pressure control installation according to claim 1, characterized in that an amplifier means is connected between the transmitter means and the electric pressure regulating means.

Claim 7

A pressure control installation according to claim 5, characterized in that said transmitter means is a potentiometer.

Claim 8

A pressure control installation according to claim 1, characterized by means for supporting the armature for substantially frictionless movement.

Claim 9

A pressure control installation according to claim 7, wherein said supporting means is a leaf spring.

Claim 10

A pressure control installation for hydraulically shifted automatic transmission of a machine having a line system for a pressure fluid comprising a source of pressure fluid for the line system, transmitter means for generating an electric output signal in dependence on an operating magnitude of the machine, control means connected in the line system for providing a control pressure for shifting of the transmission, said control means including electric pressure regulating means responsive to the electric output signal of said generating means for effecting the regulation of the control pressure in dependence on the operating magnitude, said electric pressure regUlating means including solenoid valve means having an electromagnet and including a magnetic housing and magnetic core with an annularly shaped gap therebetween, and a bell-shaped armature arranged for movement of its cylindrical rim within said annularly shaped gap such that the range of movement of said armature is effected under an essentially constant magnetic force produced by said electromagnet and said electric output signal, said control means include a further pressure regulating means, said electric pressure regulating means applying a pilot control pressure to said further pressure regulating means, and at least one working pressure supplied by said pressure source being applied to said further pressure regulating means in opposition to the pilot control pressure, said further pressure regulating means being responsive to the applied pressures for regulating the control pressure for effecting the shifting of the transmission, said further pressure regulating means including first means responsive to a predetermined pilot control pressure applied thereto for providing a constant output control pressure from said further pressure regulating means, and second means responsive to a pilot control pressure exceeding the predetermined pressure for providing an output control pressure which increases in accordance with increasing pilot control pressure within a predetermined range until a maximum pilot control pressure is obtained whereby a maximum constant output control pressure is provided, said first means including a first slide valve and a first spring means biasing the slide valve in a direction opposite to the pilot control pressure, such that the first slide valve abuts against a spring guide means in response to the predetermined pilot control pressure, and said second means including a second slide valve and a second spring means arranged between the second slide valve and said first means, said second spring means being compressed in response to the pilot control pressure exceeding the predetermined pressure and causing the second slide valve to move against a fixed abutment.

Claim 11

A pressure control installation for hydraulically shifted automatic transmission of a machine having a line system for a pressure fluid comprising a source of pressure fluid for the line system, transmitter means for generating an electric output signal in dependence on an operating magnitude of the machine, control means connected in the line system for providing a control pressure for shifting of the transmission, said control means including electric pressure regulating means responsive to the electric output signal of said generating means for effecting the regulation of the control pressure in dependence on the operating magnitude, said electric pressure regUlating means including solenoid valve means having an electromagnet and including a magnetic housing and magnetic core with an annularly shaped gap therebetween, and a bell-shaped armature arranged for movement of its cylindrical rim within said annularly shaped gap such that the range of movement of said armature is effected under an essentially constant magnetic force produced by said electromagnet and said electric output signal, said control means include a further pressure regulating means, said electric pressure regulating means applying a pilot control pressure to said further pressure regulating means, and at least one working pressure supplied by said pressure source being applied to said further pressure regulating means in opposition to the pilot control pressure, said further pressure regulating means being responsive to the applied pressures for regulating the control pressure for effecting the shifting of the transmission, said further pressure regulating means including first means responsive to a predetermined pilot control pressure applied thereto for providing a constant output control pressure from said further pressure regulating means, and second means responsive to a pilot control pressure exceeding the predetermined pressure for providing an output control pressure which increases in accordance with increasing pilot control pressure within a predetermined range until a maximum pilot control pressure is obtained whereby a maximum constant output control pressure is provided, said first means including a first slide valve and a first spring means biasing the slide valve in a direction opposite to the pilot control pressure, such that the first slide valve abuts against a spring guide means in response to the predetermined pilot control pressure, and said second means including a second slide valve and a second spring means arranged between the second slide valve and said first means, said second spring means being compressed in response to the pilot control pressure exceeding the predetermined pressure and causing the second slide valve to move against a fixed abutment.

Claim 12

A pressure control installation for controlling pressure fluid in a line system comprising a source of pressure fluid for the line system, control means connected in the line system for regulating the pressure therein including electric pressure regulating means providing a pilot control pressure and further pressure regulating means for providing an output control pressure, said further pressure regulating means being actuated by the electrically controlled pilot control pressure and including a first slide valve means acted upon by said pilot control pressure and a second slide valve means which is acted upon by a working pressure supplied by said pressure source and controlled by said further pressure regulating means in a direction opposite to said pilot control pressure, a spring guide means having a pressure element displaceable relative thereto in one direction and provided with spring abutment means as well as three spring means interconnected between said first and second slide valve means, the weakest one of said spring means being arranged between the first slide valve means and the spring guide means, the second strongest spring means being arranged with prestress between an abutment at the spring guide means and the spring abutment means whereas the third spring means having a strength intermediate the first and second spring means is supported, on the one hand, at the second slide valve means and, on the other, at the spring abutment means forcing the same against a fixed abutment.

Claim 13

A pressure control installation for controlling pressure fluid in a line system comprising a source of pressure fluid for the line system, control means connected in the line system for regulating the pressure therein including electric pressure regulating means providing a pilot control pressure and further pressure regulating means for providing an output control pressure, said further pressure regulating means being actuated by the electrically controlled pilot control pressure and including a first slide valve means acted upon by said pilot control pressure and a second slide valve means which is acted upon by a working pressure supplied by said pressure source and controlled by said further pressure regulating means in a direction opposite to said pilot control pressure, a spring guide means having a pressure element displaceable relative thereto in one direction and provided with spring abutment means as well as three spring means interconnected between said first and second slide valve means, the weakest one of said spring means being arranged between the first slide valve means and the spring guide means, the second strongest spring means being arranged with prestress between an abutment at the spring guide means and the spring abutment means whereas the third spring means having a strength intermediate the first and second spring means is supported, on the one hand, at the second slide valve means and, on the other, at the spring abutment means forcing the same against a fixed abutment.

Claim 14

A pressure control installation according to claim 10, wherein the line system connected to the pressure source includes a first line system for the electrically controlled pilot control pressure acting on the further pressure regulating means which is operatively connected with a second line system for the working pressure supplied by the pressure source by way of a throttle means.