Patent GB-1167564-A (GB)
Title: Improvements relating to Gear Boxes
IPC: F16H61/32
Filed: 1966-10-26
Abstract: 1,167,564. Change speed control. ROBERT BOSCH G.m.b.H. 26 Oct., 1966 [29 Oct., 1965], No. 47948/66. Addition to 1,112,195. Heading F2D. [Also in Division H2] In a control for a motor vehicle four-forward speed and one reverse change-speed gear, wherein gear-shift is effected by a crank member 14 rotated by an electric motor 17, the crank member having one half of a revolution for each shift step, the electric motor 17 is controlled, via a rotary follower switch 22 and transistorized voltage-dependent motor-direction-determining switches 23, 24, by transistor switches T4-T1 respectively successively conductive to provide first-fourth gears and responsive to vehicle travelling conditions, e.g. travelling speed and accelerator-pedal position, the follower switch 22 having an arm 40 which is connected by a line 39 to the switches 23, 24, has switching positions r, 1, 2, 3, 4 corresponding to the gear positions, and is driven by the crank member 14 through means (Fig. 5 or Fig. 6, not shown) ensuring a well-defined correlation between the arm switching positions and the gear positions. In Reverse, none of the transistors T4-T1 is conductive. The motor 17 drives the crank member 14 through reducing gears (16), (30). The usual cross-shift and gear-establishing movements of a gear shift lever 12 are respectively effected by a connecting rod 13, connected to the shift lever and the crank driving pin 15, and a longitudinally slotted, transversely movable, shift lever guide 20 connected by a lever 32 to a follower 28 guided in a cam groove 31 in the crank member. The transistors T4-T1 have their bases respectively connected to terminals 38-35 of an electronic circuit (not shown) controlling the transistors T4-T1 in dependence on vehicle travelling conditions, their emitters connected to the circuit positive line (0 V.), and their collectors respectively connected to the circuit negative line (-6 V.) through low-resistance resistors 63-60 and to alternate junctions of higher and equal resistance resistors 59-50 forming a voltage divider. The other alternate junctions of the resistors 59-50 are connected to the fixed contacts r, 1, 2, 3, 4, of the rotary follower switch 22. The circumferential extent of the switching arm 40 almost corresponds to the path over three adjacent contacts. The voltage dependent, motor-direction-determining switches 23, 24 comprise respectively a PNP transistor T6, controlling, via amplifying transistors T7, T8, a relay 41 operating contacts 42 for anti-clockwise motor rotation, and an NPN transistor T9 controlling, via amplifying transistors T10, T11, a relay 44 operating contacts 45 for clockwise motor rotation. The transistors T6, T9 have their bases connected via the line 39 to the switching arm 40, their collectors respectively connected to the bases of the amplifying transistors T7, T10 and their emitters so respectively connected to the junctions of resistors 46, 47 and 47, 48 of a voltage divider that their potentials stand at approximately -3À5 V. and -2À5 V In the on" " and "off" positions of the switches 23, 24, the contacts 42, 45 respectively connected the armature 43 of the motor to the positive line and, through the field winding, the negative line. On return of the switches to " off," a time device (not shown) is triggered to close a switch 49 for 2 milliseconds to effect, with the short circuiting of the armature coil, sharp braking of the armature to prevent its overrunning. In Fig. 5 (not shown), the contacts r, 1, 2, 3, 4 are disposed in one plane. The arm 40 is connected to a Geneva star wheel (7) which is driven by pins (8), (9) disposed at 180 degrees on the crank member 14. In Fig. 6 (not shown), the arm 40 is partly let into an insulating body (19) rotatably fast with but axially slidable on a spindle (5) fast with the crank member 14, the arm having a projecting portion forming the slider which is helical and extends almost a full revolution of the body (19). The arm 40 is also connected to a helical contact (21) which has several turns about the body and slides in a fixed contact (25) connected to the line 39. The contacts r, 1, 2, 3, 4 are axially staggered and disposed in two diametrically opposite lines. Operation.-As shown, Second gear is engaged. The transistors T1, T2 are blocked and the transistors T3, T4 conductive, so that the junction of the resistors 55, 56 is at 0 V., the junction between 53, 54 is almost at - 6 V. and therefore the junction between 54, 55, the contact 2 and the bases of the transistors T6, T9 are at - 3 V. In consequence, T6, T9 are blocked and the motor 17 is switched off. In, e.g., shift to Third gear, T2 is also made conductive so that the 54, 55 junction jumps to 0 V. and the 52, 53 junction is at - 3 V. T9 becomes conductive and actuates the contacts 45 to rotate the crank member 14 in the direction shown by the arrow (Fig. 2). During the first quarter turn the shift lever 12 is moved to the centre of the guide 20 whereupon a rise portion of the cam groove 31 radially outwardly moves the follower 28 to cross-shift the guide 20 to the III-IV shift plane, the shift lever then being moved to the III position during the second quarter turn. Simultaneously the switching arm 40 is moved from the contact 2 to the contact 3. After approximately one sixth of this distance the contact 3 is engaged by the slider of the arm 40 so that the contacts 2, 3 are bridged, whereby T9 receives a base potential of -1À5 V. and remains conductive. Shortly before the arm 40 reaches its third gear position the connection with contact 2 is broken so that T9 jumps to - 3 V. and the motor 17 is switched off. If, as a consequence of possible overrunning during 2-3 shift, the contact 4 is touched, T6 becomes conductive and reverses the motor 17 to break this contact. The contacts r, 1, 2, 3, 4 and (25) may be gas protected contacts with the arm 40 provided with contact-actuating permanent magnets; or the switch 22 may be provided with gold contacts with the arm constructed as an actuating cam.