Gear changing means for change-speed gearboxes

Claim 2

In a device for semi-automatically or automatically changing the gear ratio in a multi-ratio change speed mechanical synchromesh gearbox for motor vehicles, said gearbox having components to be shifted to change said gear ratio, and said device comprising an electric or electronic means for controlling the automatic sequence of each gear change, a source of fluid under pressure, an actuating cylinder for moving said components of the gearbox to be shifted to effect gear change and electromagnetic control valves connected electrically to the said controlling means, the said actuating cylinder being connected by pipes to said source of fluid under pressure and the said control valves being arranged in said pipes to provide fluid under pressure to said actuating cylinder in response to commands received from said controlling means to effect gear changing; the combination of fluid flow control means and fluid pressure control means arranged in said pipes between said source of fluid under pressure and said cylinder, said control means controlling the rate of fluid flow and the pressure, respectively, of the fluid flowing through the said pipes during a gear change.

Claim 3

The device of claim 1 wherein the said fluid flow control means comprises a throttle and means for by-passing the said throttle responsive to fluid pressure down-stream of said throttle.

Claim 4

The device of claim 2, wherein the said fluid flow control means is arranged up-stream of said fluid pressure control means, a second throttle is provided down-stream of said fluid pressure control means, and said fluid control means is connected by a pipe to a point between the fluid pressure control means and the second throttle to control the said by-passing of said throttle of the fluid flow control means.

Claim 5

The device of claim 1 having a plurality of actuating cylinders.

Claim 6

The device of claim 4 wherein each said actuating cylinder has three chambers, a piston movable through the chamber and carrying an outwardly projecting piston rod associated with the components in the gearbox to be shifted, and separate means for delivering said fluid under pressure to each chamber comprising a two-position three-way control valve.

Claim 7

The device of claim 5 in which the cylinder has a projecting piston rod capable of occupying three stable positions, two end positions corresponding to the engagement of different ratios in the gear box and an intermediate neutral position, said piston rod being connected to a first piston in the cylinder, a second piston connected to the first piston by a second piston rod, means in the wall of the cylinder for stopping the second piston while the first piston is spaced from the adjacent end of the cylinder to thereby divide the cylinder into three chambers, and separate means for delivering fluid under pressure into each chamber.

Claim 8

The device of claim 1 wherein the means for controlling the fluid pressure is responsive to the synchronizing forces of each gear ratio.

Claim 9

The device of claim 1 wherein the flow rate control means is by-passed by a conduit provided with an electro-magnetic two-position two-way control valve connected to said electric or electronic actuating means, said control valve permitting flow of fluid to the cylinder when in its open position.

Claim 10

In a device for semi-automatically or automatically changing the gear ratio in a multi-ratio change speed mechanical synchromesh gearbox for motor vehicles, said gearbox having components to be shifted to change said gear ratio, and said device comprising an electric or electronic means for controlling the automatic sequence of each gear change; a system for actuating said components to change the gear ratio comprising a three-position cylinder, a first piston in said cylinder carrying a first piston rod, a lever coupling the first piston rod to a said component, a second piston, a second piston rod connecting the pistons together, and means for introducing a fluid under pressure into the cylinder comprising an accumulator, conduits leading from the reservoir to the cylinder and a pump for transferring fluid under pressure from the accumulator to the cylinder, a first electro-magnetically acutated control valve responsive to said sequence control means and disposed in a conduit between the accumulator and cylinder, a conduit extending between said first valve and said cylinder between said pistons and a separate conduit extending between the said first control valve and said cylinder between the second piston and the adjacent end of the cylinder, a second electro-magnetically actuated control valve responsive to said sequence control means and in a conduit which extends between the first control valve and between the pistons in the cylinder, a third electro-magnetically actuated control valve responsive to said sequence control means and in the conduit which extends between the first control valve and between the second piston and the end of the cylinder, means for flow of fluid from the valves to the accumulator, a first by-pass conduit between said accumulator and said second and third control valves by-passing said first control valve, means comprising a throttle for restricting the rate of flow of fluid through the said by-pass conduit, means downstream of the said throttle for restricting the pressure in said by-pass conduit, and a second by-pass conduit connected to said first by-pass conduit and extending from upstream of said throttle to downstream of the pressure restricting means for flow of fluid around said throttle at a predetermined fluid pressure downstream of the throttle.

Claim 11

In a device for semi-automatically or automatically changing the gear ratio in a multi-ratio change speed mechanical synchromesh gearbox for motor vehicles, said gearbox having components to be shifted to change said gear ratio, and said device comprising an electric or electronic means for controlling the automatic sequence of each gear change; a system for actuating said components to change the gear ratio comprising a three-position cylinder, a first piston in said cylinder carrying a first piston rod, a lever coupling the first piston rod to a said component, a second piston, a second piston rod connecting the pistons together, and means for introducing a fluid under pressure into the cylinder comprising an accumulator, conduits leading from the reservoir to the cylinder and a pump for transferring fluid under pressure from the accumulator to the cylinder, a first electro-magnetically acutated control valve responsive to said sequence control means and disposed in a conduit between the accumulator and cylinder, a conduit extending between said first valve and said cylinder between said pistons and a separate conduit extending between the said first control valve and said cylinder between the second piston and the adjacent end of the cylinder, a second electro-magnetically actuated control valve responsive to said sequence control means and in a conduit which extends between the first control valve and between the pistons in the cylinder, a third electro-magnetically actuated control valve responsive to said sequence control means and in the conduit which extends between the first control valve and between the second piston and the end of the cylinder, means for flow of fluid from the valves to the accumulator, a first by-pass conduit between said accumulator and said second and third control valves by-passing said first control valve, means comprising a throttle for restricting the rate of flow of fluid through the said by-pass conduit, means downstream of the said throttle for restricting the pressure in said by-pass conduit, and a second by-pass conduit connected to said first by-pass conduit and extending from upstream of said throttle to downstream of the pressure restricting means for flow of fluid around said throttle at a predetermined fluid pressure downstream of the throttle.

Claim 12

The device of claim 9 wherein the system has a second throttle in the conduit between the pressure-restricting means and the second and third valves and the second by-pass extends from downstream of the first tHrottle to upstream of the second throttle and downstream of the pressure-restricting means.