| 摘要 |
970,218. Change-speed control. CENTRE DE RECHERCHES DE PONT-A-MOUSSON. Feb. 1, 1963 [Feb. 13, 1962], No. 4170/63. Heading F2D. [Also in Division G1] In a vehicle change-speed gear providing four forward ratios and reverse, shifts between the second ratio and the upper ratios are effected automatically under the control of an outputspeed responsive hydraulic governor. As shown a gear-box B is controlled by the application of band brakes which are engaged by hydraulic jacks V AR , V 1 -V 4 which are controlled by valves D 1 -D 4 which are arranged in series and supplied by a pump 2. The pump 2 also supplies liquid to a valve P which controls servomotors S 3 , S 4 which control the valves D 3 , D 4 . The hydraulic governor comprises a bladed rotor 19 connected by gears E to the output shaft N of the gear-box B, the rotor 19 being rotatably mounted within a stationary cylindrical casing 11 to the centre of which liquid is supplied at a given head through a line 15 from a tank 16. The centrifugal pressure created by the rotation of the rotor 19 is communicated through a port 17 in the periphery of the casing 11 and a line 18 to a jack T having a flexible diaphragm 23 which actuates the valve P against the loading of a spring r 5 . A restriction 18‹ in the line 18 delays the response of the jack T to changes in pressure produced in the governor R to avoid hunting. In operation the valves D 1 , D 2 are actuated manually, the valve D 1 being operable against the pressure of a spring r 1 to a position pressurizing the jack V AR , and biased by the spring to a position in which the jack is opened to exhaust and pressure is supplied to the following valve D 2 . Valve D 2 has three positions, a central position b 2 (shown) in which the jacks V 1 -V 4 are opened to exhaust to give neutral, a position a 2 to which it is biased by a spring r 2 in which the jack V 1 is opened to exhaust and liquid is supplied to the following valve D 3 , and a position c 2 in which liquid is supplied to the jack V 1 to give a first ratio. The valve D 3 has a position b 3 in which liquid is supplied to a jack V 2 for the second ratio and is moved to a position a 3 by the servomotor S 3 to admit liquid to the valve D 4 , which is biased by its spring r 4 to a position a 4 in which liquid is supplied to the jack V 3 for third: ratio, and is displaceable by the servomotor S 4 to a position b 4 in which liquid is supplied to the jack V 4 for the fourth ratio. The valve P is biased by the spring r 5 to the position shown in which the servomotors S 3 , S 4 are open to exhaust, so that with the manually controlled valves D 1 , D 2 in the appropriate positions the second gear ratio is obtained. With increasing pressure in the jack T the valve P is moved to a central position in which liquid from the pump 2 is supplied through a line 26a and the valve P to the servomotor S 3 to give the third ratio, and finally as the pressure in the servomotor T increases the valve P is moved to a third position in which liquid is supplied to both servomotors S 3 , S 4 to give the fourth ratio. An engine M drives the input shaft A of the gear-box V through an hydraulic coupling C. The loading of the spring r 5 may be varied in accordance with the position of the accelerator pedal. In a modification the valves D 3 , D 4 are actuated by electromagnets under the control of the jack T which engages contacts in the circuits of the electromagnets. |
