Patent GB-1383103-A (GB)
Title: Gear-shift arrangements
IPC: F16H61/28
Filed: 1972-05-12
Abstract: 1383103 Change-speed control ROBERT BOSCH GmbH 12 May 1972 [18 May 1971] 22306/72 Heading F2D  In an air or liquid pressure operated gear shift on a motor vehicle having a selecting motor 7 and a gear-establishing motor 8 working in planes at right angles, the selector motor 7 is a doubleacting cylinder with a pressure supply 11, 12 to both ends through a two-way check-valve 13, and outlets 14 ... 17 arranged along the length of the cylinder for stepwise control by the piston 9, the outlets being selectively connected to exhaust 4 through respective solenoid valves 18 ... 21, the gear-establishing motor 8 being a three-position double-acting piston motor. Six embodiments are described, the selecting motor and its control being the same in all eases. Control may be manual or automatic by electronic means, not described, with consequential disengagement of the main clutch and synchronizing, and manual operating levers may be fitted directly to both piston-rods. Gear selecting motor.-Action of the selecting motor 7 is as follows. To move the selector piston 9 e.g. one step left from the position shown, the solenoid valve 19 is energized to exhaust the port 15 and hence the left end of the cylinder, whilst the two-way check valve 13 maintains pressure at its right end, so that the piston 9 moves left until it covers the exhausted outlet 15, whereupon pressure is applied through the two-way valve 13 equally to both ends of the cylinder and the piston 9 stops in the selected position. In Fig. 1 the selector piston-rod 9<SP>1</SP> has keys 26 which selectively engage splines in pivoted gear-shifters 22 ... 25, gear establishment being produced by the motor 8 turning the rod 9<SP>1</SP> through a splined arm 28. In Fig. 2,not shown, Fig. 3, and Figs. 4 to 6, not shown, the selector piston-rod 9<SP>1</SP> has rack teeth (41) rocking an axially movable and rotatable toothed sector (42), having a finger (43) selectively engaging gear shifters (22<SP>11</SP> ... 25<SP>11</SP>) grouped arcuately around the rod, the toothed sector (42) being secured to the piston-rod (29<SP>1</SP>) of the gear establishing motor 8 for axial movement to operate the selected shifter. Gear establishing motor.-In Fig. 1, neutral and two gear establishing positions of the motor 8 are determined by its piston 29 covering outlets 34, 36, connected selectively to exhaust by solenoid valves 37, 39, the two sides of the piston 29 being supplied with pressure through a twoway check-valve 33 as for the selecting motor above described. Fig. 2, not shown, is similar but here the three solenoid valves (44, 46) act as pilots to ball valves controlling the cylinder ports. The pressure supply 5, 6 to both the selecting and establishing motors also have separate shut-off solenoid valves (57, 58). In Fig. 3, the three-position gear on establishing motor 68 has a piston 69 with a central enlargement 71 forming a stop for sliding sealed rings 73, the cylinder also having a central stop shoulder 72 which locates the neutral position when pressure 76, 77 is applied to both ends of the cylinder, gear establishing positions being assumed when pressure is applied singly to either appropriate end. Solenoid valves 78, 79 act as pilots to respective ball valves 80, 81, energization of a solenoid valve 78 or 79 directing pressure 6 to the left end of a piston 86 which lifts the spring-loaded ball 90 off its seat to supply pressure 6 to the appropriate line 76 or 77. At the end of a gear establishing movement pressure equalizes on both sides of the piston 86 which then returns to the position shown, allowing the ball 90 to re-seat. Fig. 4, not shown, uses a gear establishing piston with a central enlargement (109) and a single sliding ring (112) on a spigot (111) at one side of the enlargement, control being as in Fig. 3. In Fig. 5, not shown, the toothed sector which meshes the selector sack is arranged between two double-acting cylinders (120, 120<SP>1</SP>) each containing a piston on the common rod, each piston having a ring (125, 125<SP>1</SP>) slidable between stops on the piston. The inner sides of both pistons are exhausted, and the outer sides receive pressure selectively through a control as in Fig. 3. In Fig. 6, not shown, the gear establishing piston-rod (140) is slidable between one end of the cylinder and a central stop (144) therein, pressure being applied to opposite sides of a piston (139) thereon for full gear establishing travel. Neutral is established by applying pressure to one end (146) of this piston (139) and to the remote face of a separate piston (142) having a stem (143) abutting the first piston (139). Control is by three solenoid pilot valves (148, 150, 152) operating ball valves (149, 151, 153) as in Fig.3. One, (148), of these solenoid valves is open when de-energized, whilst the other two (150, 152) are closed when de-energized, so that only one needs to be energized for a gear establishing movement in either direction or for neutral.  Rotary pistons may replace the linear ones shown.