Patent GB-846091-A (GB)
Title: Improvements in or relating to hydro-kinetic and clutch transmission apparatus for vehicles
Inventor: GATISS ALBERT LESLIE
IPC: F16H45/00
Filed: 1956-01-06
Abstract: 846,091. Friction clutches; gearing for stopping and starting machinery; change-speed gear. BROCKHOUSE ENGINEERING Ltd. Jan. 7, 1957 [Jan. 6, 1956; Jan. 8, 1956], Nos. 489/56 and 17733/56. Class 80 (2). The turbine of a fluid coupling or torque converter for motor vehicles is in series with an hydraulically-engaged friction clutch connecting it to its driven member, the hydraulic circuit by which the clutch is engaged including the working fluid in the coupling or converter. As shown, an engine flywheel 40, Fig. 2, carries the impeller 36 of a torque converter having a reaction element 38, connected by a one-way brake 42 to a stationary casing sleeve 43, and a turbine 37. A friction clutch disc 59 is splined to rotate with but slide axially upon a driven sleeve 32. The impeller 36 drives through a gear 47 to a pump 46 which draws in oil from a surrounding casing 41, and supplies it to a valve 65 which can be so conditioned that the oil then passes through a shaft passage 48 to the torque converter 30. As the impeller 36 rotates, some of the oil passes through a gap 57 between the turbine 37 and the driving flywheel 40 to a space 58 between the end face of the flywheel and a clutch engaging piston 52. The piston 52 is thus forced rightwards of Fig. 2 to engage the clutch disc 53 with the turbine 37, to transmit drive to the sleeve 32. The clutch-engaging piston 52 is splined at its periphery 54 to a ring 55 fast with the turbine 37. The turbine 37 is itself capable of limited axial movement leftwards of Fig. 2, so that with increasing centrifugal force acting on the working oil within the torque converter, movement of the impeller increases the frictional force engaging the clutch disc 59. To disengage the clutch, the valve 65 is actuated to discontinue the supply of oil under pressure to the torque converter, and simultaneously supplies oil under pressure through a shaft duct (not shown) and a radial port 61 to spaces 50 on either side of the clutch disc 59, so that the clutch engaging piston 52 is moved leftwards away from the clutch disc. Holes 59a in the clutch disc interconnect the opposite sides thereof. The valve 65, Fig. 4, alternatively connecting the spaces 50, 58 to the supply of oil under pressure, comprises two piston-shaped parts 71, 72 connected by a port 66 to the oil pump 46. A port 67 leads to the clutchengaging space 58, and a port 68 leads to the clutch disengaging space 50. In the position shown, the port 68 is open to atmospheric pressure within the casing 41 so that the disengaging space 50 is free of pressure, and the pump 46 supplies oil through the ports 66, 67 and the passage 48 to the torque converter 30 and clutch-engaging space 58. The valve piston 65 is slidden axially to connect the port 68, &c., to the port 66 and pump 46, and thus disengage the clutch, by turning a shaft 76 carrying a lever 77. The shaft 76 may be turned by depressing the clutch pedal of a vehicle containing the torque converter &c., or alternatively the shaft 76 may be turned by speed and/or torque responsive mechanism. When the lever 77 has moved sufficiently to disengage the clutch 50, it abuts the end 79 of a plunger 80, Fig. 2, which, on further movement of the shaft and lever 76, 77, engages a brake disc 88 fast with the driven sleeve 32. Following disengagement of the clutch disc 59, the drive sleeve 32 can accordingly be braked to rest. In a modification, Fig. 9 (not shown), an hydraulically-operated brake replaces the mechanically-operated brake 80, the valve 65 being modified so that movement beyond the clutch disengaging position opens an additional port through which oil is supplied to cause brake engagement. So that excessive pressure shall not build-up in the clutch disengaging space 50, a pressure release valve 92, Fig. 2, is provided between the ports 68, 61. A further by-pass friction clutch may be provided in parallel with the torque converter 30, to connect the driving flywheel 40, Fig. 14, to the turbine 37. A friction clutch ring 101 is splined at 102 for rotation with the turbine 37 and engages a shell 99 fast with the flywheel 40. A clutch-engaging piston 104 can be biased by the admission of oil under pressure through a port 108 and a shaft duct 106 to a space 109 to engage with the clutch ring 101. The clutch piston 104 is splined at 105 to engage with the flywheel 40. To engage the direct drive clutch 101 while the series clutch 59 is simultaneously engaged, the pressure in the space 109 must be greater than the pressure in the space 58 which is acting upon the piston 52 to engage the series clutch 59. To achieve this, a pressure reducing valve 110, Fig. 16, is placed between the port 66a to which oil is supplied from the pump 46 and the port 66 leading to the valve 65. As before, the valve 65 controls the supply of oil under pressure to the ports 67, 68 causing engagement and disengagement, respectively, of the series clutch 59. The pressure relief valve 110 comprises a negative feedback passage 110b through which pressure acts to assist a spring 110c tending to move the pressure reducing valve piston 110a to a position in which it closes the port 66. Thus the pressure supplied through the port 66 to the valve 65 is always less than the pressure of the oil supplied by the pump to the port 66a. The pump 46 simultaneously supplies oil under full pressure through a pipe 117 to a valve 115 controlling the engagement and disengagement of the by pass clutch 101. The valve 115 is formed with piston parts 120, 121 which either direct oil through the port 108 and a conduit 118 to the clutch engaging space 109, or alternatively connects the space 109 through the port 108 to a port 119 leading back to the storage space within the surrounding casing 41. The two valves 65, 115 may be interconnected m such a way as to ensure that the valve 115 is only moved to a position causing the direct drive by-pass clutch 101 to be engaged after the valve 65 has been conditioned to engage the series clutch 59. The valve 115 may be operated manually or automatically in response speed or torque characteristics. The control valve 65 described as controlling the series clutch arrangement of Fig. 2 may be modified to contain a pressure relief valve, replacing the pressure relief valve 92. In this form, the valve 65, Fig. 21, again has an inlet port 66 and ports 67a, 68a leading to the clutch engaging and disengaging spaces 58, 50. A pressure reducing valve piston 128 is biased rightwards of the Figure by a spring (not shown) and has a stem 129 of reduced crosssection. When the valve 65 is conditioned to connect the clutch disengaging port 68a to the pressure inlet port 66, oil pressure acts upon the head of the piston 128 to move it leftwards to the position shown against the bias of its spring. A parallel passage 125 is thus opened, so that oil is supplied round the stem 129 of the valve piston to the port 67a and the clutchengaging space 58. The pressure of the oil supplied to the valve stem 129, &c. acts upon the base of the valve piston 128 to assist its spring in moving it towards a closed position, the valve piston 128 eventually taking up an equilibrium position with the pressure in the passage 125 and the port 67a less than that supplied from the pump 46. Thus oil is retained in clutch-engaging space 58 at a pressure lower than that in the clutch-disengaging space 50, and shock to or distortion of the clutch piston 52 when the series clutch 59 is disengaged is avoided. In Fig. 22, the torque converter 30, the series clutch 59, and the direct drive by-pass clutch 1.01 are shown incorporated with a motor vehicle change-speed gear transmission. The turbine 37 and the series clutch 59 drive through the sleeve 32 to a gear 137 meshing a gear 139 connected through a one-way clutch 142 to a countershaft 141. The direct drive by-pass clutch 101 when engaged connects the flywheel 40 to a shaft 135 carrying a gear 138 meshing a gear 140 fast on the countershaft 141. A gear 145 fast on the countershaft meshes a gear 144 selectively clutched by conventional synchromesh mechanism 143 to a final output shaft 35. The synchromesh mechanism 143 is selectively operable to connect the gear 138 and the direct drive shaft 135 directly to the output shaft 35. A gear 147 can be slidden axially on the output shaft 35 either to engage with a gear 148 on the countershaft 141 for a low-forward ratio, or alternatively to mesh with an idler 149 meshing a gear 155 on the countershaft for reverse. The synchromesh mechanism 143 and the gear 147 are actuated to establish the various ratios by. conventional selector rods moved by a manually-operated lever 146. A trigger 182 on a handle 146 is connected to the valve 65 controlling the series clutch 59. On grasping the handle 146 to engage one or other of the ratios, the valve 65 is operated to disengage the series clutch 50, so that transmission of drive through the torque converter 30 is interrupted. The direct drive clutch 101 is engaged and disengaged under the joint control of output speed and accelerator pedal setting. A centrifugal governor 134, Fig. 23, is driven from a gear 152, Fig. 22, at a speed proportional to the speed of the output shaft 35. Increasing speed of the centrifugal governor tends to move a shaft 159 axially against the bias of a spring 165 to turn a lever 160 about its pivot point 161 and close a switch 169. Movement of the shaft 159 leftwards of Fig. 23 is opposed by depression of the vehicle accelerator pedal 167 to increase the compression of the spring 165. Closing the switch 169 energizes a solenoid 170, Fig. 22, which conditions the valve 115 to engage the direct drive clutch 101. Specifications 639,675 and 702,840 are referred to.