GB2028937A - Shock Control Arrangement in Hydraulic Control System of Automatic Power Transmission - Google Patents
Shock Control Arrangement in Hydraulic Control System of Automatic Power Transmission Download PDFInfo
- Publication number
- GB2028937A GB2028937A GB7927404A GB7927404A GB2028937A GB 2028937 A GB2028937 A GB 2028937A GB 7927404 A GB7927404 A GB 7927404A GB 7927404 A GB7927404 A GB 7927404A GB 2028937 A GB2028937 A GB 2028937A
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- pressure acting
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/04—Smoothing ratio shift
- F16H61/06—Smoothing ratio shift by controlling rate of change of fluid pressure
- F16H61/065—Smoothing ratio shift by controlling rate of change of fluid pressure using fluid control means
- F16H61/067—Smoothing ratio shift by controlling rate of change of fluid pressure using fluid control means using an accumulator
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Control Of Transmission Device (AREA)
Abstract
In an automatic power transmission having a transmission mechanism including fluid operated frictional elements, a shock control arrangement provided in the hydraulic control system for the transmission mechanism, comprising a single pressure accumulator unit (20) which takes up the hydraulic pressure to be applied to any of the frictional elements during selection of the automatic forward drive range or reverse drive range or during upshifting between the higher and lower gear ratios in the automatic forward drive range, the level at which the pressure accumulator unit (20) is to commence taking up of the fluid pressure for one of the frictional elements being varied with engine load. The accumulator unit 20 includes a piston 23 biased by a spring 24 and three expansible fluid chambers 25, 26, 27 each of which can communicate with the actuator of a respective frictional element (clutch 1, servo unit 3 of a band brake clutch, 2). <IMAGE>
Description
SPECIFICATION
Shock Control Arrangement in Hydraulic
Control System of Automatic Power
Transmission
The present invention relates to an arrangement for reducing select shock and shift shock in an automatic transmission having a transmission mechanism including fluid operated frictional elements which are actuated to select automatic forward drive and reverse drive ranges and to make shifts between the predetermined higher and lower gear ratios in the automatic forward drive range.
In such a transmission, when the driver changes the manual valve from the neutral (N) range to the forward running (D) range, a rear clutch is supplied with a line pressure causing engagement thereof to permit the forward running of the vehicle. Further, when the manual valve is changed from the N range to the reverse (R) range, the line pressure is supplied to the front clutch and to the low-and-reverse brake actuating those frictional elements to permit the reverse running of the vehicle. During such a change of the manual valve from the N range to the D range or to the R range, when the pressure is supplied to the corresponding frictional elements too suddenly, the so-called select shock is produced.
In the automatic transmission, with the manual valve in the D range, when the vehicle after starting reaches a predetermined speed, the line pressure is additionally supplied from the manual valve and through a 1-2 shift valve responsive to a governor pressure corresponding to the vehicle speed to a servo apply chamber of a second brake to actuate the same so that an automatic upshifting from the first to the second speed is effected. In this case, when the servo apply chamber is supplied suddenly with the line pressure, the second brake is operated too quickly acompanying the so-called shift shock.
Various proposals have heretofore been made to reduce the select shock and the shift shock individually.
It is an object of the present invention to provide a shock reducing arrangement for an automatic transmission by which the abovementioned shocks can be reduced by means of a single accumulator only.
In order to ensure that the accumulator reduces the shift shock during the upshifting to the second speed, operation of the accumulator has to be initiated in such a manner that with the small throttle opening and hence with the small engine output, the accumulater operates even when the servo apply pressure of the second brake for selecting the second speed is relatively low, and that with the high throttle opening and hence with the high engine output, the accumulator operates only after the servo apply pressure becomes relatively high.On the contrary, if the operation of the accumulator is initiated at a constant pressure level independent of the throttle opening, the shift shock cannot be reduced at a low throttle opening since the threshold pressure level to initiate the operation of the accumulator in such a case becomes too high, and at a high throttle opening, the threshold pressure level becomes too low resulting in excessive slip of the second brake by which the life of this brake will be shortened.
According to the present invention, the line pressure during the upshifting is applied to the piston of the accumulator in opposition to the servo apply pressure. By this measure, since the line pressure is regulated by the throttle pressure corresponding to the throttle opening, the threshold pressure for operating the accumulator can be increased in proportion to the throttle opening.
The present invention will now be described in detail with reference to the preferred embodiments shown in the accompanied drawings, in which:
Fig. 1 is a schematic system diagram showing an embodiment of the transmission mechanism of an automatic transmission;
Fig. 2 is a diagram showing a hydraulic control circuit of the automatic transmission incorporating the shock reducing arrangement according to the present invention;
Fig. 3 is a diagram showing hydraulic circuit of the shock reducing arrangement according to one embodiment of the present invention;
Figs. 4 and 5 are diagrams corresponding to
Fig. 3 and showing two other embodiments of the present invention; and
Fig. 6 is a diagram showing the operational pressure characteristics of the accumulator with reference to the throttle opening.
Fig. 1 shows schematically the internal construction of a power transmission mechanism of an automatic transmission of the three forward speed and one reverse speed type. The mechanism comprises a crankshaft 100 driven by an engine, a torque converter 101, an input shaft 102, a front clutch 104, a rear clutch 105, a second brake 106, a low-and-reverse brake 107, a one-way clutch 108, an intermediate shaft 109, a first planetary gear group 110, a second planatary gear group 111, an output shaft 112, a first governor valve 1 13, a second governor valve 1 14, and an oil pump 115. The torque converter 101 comprises a pump impeller P, a turbine runner T, and a stator or reaction member S.The pump impeller P is driven by the crankshaft 100 to circulate the torque converter hydraulic oil contained therein and transfer the torque to the turbine runner T fixedly mounted on the input shaft 102. This torque is then transferred to a reduction gear train by the input shaft 102. The stator S is mounted on a sleeve 116 with a oneway clutch 103 positioned therebetween. This one-way clutch 103 ailows the stator S to rotate in a same direction with the rotation of the crankshaft 100, namely, in the direction shown by an arrow (hereinafter termed as the forward direction) but it does not allow rotation in the opposite direction (hereinafter termed as the opposite direction).The first planetary gear group 110 comprises an internal gear 11 7 fixed to the intermediate shaft 109, a sun gear 11 9 fixed to a hollow transmission shaft 11 8, two or more planet pinions 120 meshed with both the internal gear 11 7 and the sun gear 119 and rotatable about their own axes and at the same time able to revolve round the sun gear, and a front planet carrier 121 fixed to an output shaft 112 and carrying the planet pinions 120.The second planetary gear group 111 comprises an internal gear 122 fixed to the output shaft 112, a sun gear 123 fixed to a hollow transmission shaft 11 8, two or more planet pinions 124 meshed with both the internal gear 122 and the sun gear 123, respectively and being able to rotate about their own axes and at the same time to revolve round the sun gear, and a rear planet carrier 125 carrying said planet pinions 124. The front clutch 104 couples the input shaft 102 driven by the turbine runner T with the hollow transmission shaft 118 rotating jointly with the two sun gears 119 and 123. The rear clutch 105 couples the input shaft 102 with an internal gear 11 7 of the first planetary gear group 110 via the intermediate shaft 109.By operating the second brake 106 by tightly gripping the periphery of a drum 1 26 fixed on the hollow transmission shaft 118, the two sun gears 119 and 123 are fixed.
The low-and-reverse brake 107 fixes the rear planet carrier 125 of the second planetary gear group 111. The one-way clutch 108 allows the rear planet carrier 125 to rotate in the forward direction but does not allow rotation in the opposite direction. A first governor valve 11 3 and a second governor valve 114 are fixedly mounted on the output shaft 112 so as to produce a governor pressure responsive to the speed of the vehicle.
Hereinafter, operation of the power transmission mechanism with the select lever in "D" position (automatic power transmission forward drive) will be explained.
In this case, at first, only the rear clutch 105 is coupled, which is an input clutch for the forward drive running. The power from the engine, transmitted through the torque converter 101, is transferred to the internal gear 11 7 of the first planetary gear group 110 via the input shaft 102 and the rear clutch 105. The internal gear 11 7 forces the planetary gear 120 to revolve in the forward direction. Therefore, the sun gear 11 9 rotates in the opposite direction and this causes the jointly rotating sun gear 123 of the second planetary gear group 111 to rotate in the opposite direction and hence the planetary gear 124 of the second planetary gear group 111 to revolve in the forward direction.The one-way clutch 108 prevents the sun gear 123 allowing the rear planet carrier 125 to rotate in the opposite direction and acts as a forward reaction brake. By this arrangement, the internal gear 122 of the second planetary gear group 111 rotates in the forward direction. Accordingly, the output shaft 112 jointly rotating with the internal gear 122 also rotates in the forward direction so as to produce the forward first speed range reduction ratio. If the vehicle speed increases from this condition and if the second brake 106 is actuated, the power delivered through the input shaft 102 and the rear clutch 105 is transferred to the internal gear 11 7 just as in the case of the first speed range. The second brake 106 holds the drum 1 26 stationary and prevents rotation of the sun gear 119 so that it functions as a forward reaction brake.Accordingly, the planet pinion 120 rotates about its axis and revolves round the stationary sun gear 11 9. Therefore, the front planet carrier 121 and the output shaft 112 coupled thereto rotate forwardly at a reduced speed but higher than the first speed range so as to produce reduced ratio of the forward second speed range. If the vehicle speed increases further to release the second brake 106 and to couple the front clutch 104, the power transmitted to the input shaft 102 is on one hand transferred via the rear clutch 105 to the internal gear 11 7 and on the other hand transferred to the sun gear 11 9 via the front clutch 104.Accordingly, the internal gear 11 7 and the sun gear 119 are interlocked and together with the front planet carrier 121 and the output shaft 112 rotate forwardly. All these members rotate at the same speed to produce the forward third speed range. In this case, the front clutch 104 and the rear clutch 105 correspond to an input clutch and there is no reaction brake since an increase of the torque by the planetary gears is not effected.
Operation of the power transmission mechanism with the select lever placed at rhe "R" position (reverse running) will be explained.
In this case, the front clutch 104 and the lowand-reverse brake 107 are coupled. The power delivered from the engine and transmitted through the torque converter 101 is conveyed to the sun gears 11 9 and 123 via the input shaft 102, the front clutch 104 and the drum 126. In this case, since the rear planet carrier 125 is fixed by the low-and-reverse brake 1 07, the internal gear 122 rotates oppositely at a reduced speed according to the forward rotation of the sun gear 11 9. The output shaft 11 2 jointly rotating with said internal gear 122 also rotates in opposite direction and the reduced reverse running speed is delivered.
Fig. 2 shows a hydraulic control circuit of the automatic transmission of which shift a controlling portion is incorporated with the shock reducing device according to the present invention. The system comprises an oil pump 13, a pressure regulator valve 128, a pressure booster valve 129, a torque converter 101, a manual valve 130, a first governor valve 113, a second governor valve 114,a 1-2shiftvalve 131,a2- 3 shift valve 132, a throttle modulator valve 133, a pressure modifier valve 134, a second lock valve 135, a 2-3 timing valve 136, a solenoid downshift valve 137, a throttle back up valve 138, a vacuum throttle valve 139, a vacuum diaphragm 140, a front clutch 1, a rear clutch 2, a
second brake 4, a servo cylinder 3, a low-and
reverse brake 107, an accumulator 20 according
to the present invention and the hydraulic
pressure circuits coupling those frictional
elements. The oil pump 13 is driven by the engine
through the crankshaft 100 and the pump
impeller P of the torque converter 101 and
circulates the hydraulic oil continuously to a line
pressure circuit 144 during the operation of the
engine after pumping the oil from a reservoir 142 through a strainer 143 for removing any harmful dust.
The oil is adjusted to assume a predetermined pressure by a pressure regulator valve 128 and is passed to the torque converter 101 and the
manual valve 130. The pressure regulator valve
128 comprises a spool 172 and a spring 173. The spool 1 72 is biassed by the spring 173 and in addition to it the throttle pressure of a circuit 1 65 via a spool 1 74 of a pressure booster valve 129 and the line pressure of a circuit 13 are applied in a direction to counteract the line pressure from a circuit 144 being applied to upstream of the spool
172 through an orifice 1 75 and also a pressure being applied likewisely from a circuit 1 76.The operational hydraulic pressure of the torque converter 101 is fed to a circuit 145 via a pressure regulator valve 128 and is kept at a pressure higher than a certain value by a pressure keeping valve 146. If the abovementioned certain pressure is exceeded, the pressure keeping valve
146 opens and the hydraulic oil is passed to a rear lubricating portion of the power transmission system. If this lubricating oil pressure is too high, a relief valve 148 opens to decrease the pressure.
Whereas to the front lubricating portion of the power transmission system, the lubricating oil is supplied from the circuit 145 by opening a front lubrication valve 149. A manual valve 1 30 is provided which is a manual flow direction switching valve. This manual valve 130 comprises a spool 1 50 which is coupled to the select lever (not shown) via a linkage. By the respective selecting operation, the spool 1 50 is moved to switch the hydraulic pressure path of the line pressure circuit 144. The condition as indicated in
Fig. 2 is that the select lever is set in the neutral position (N), where the line pressure circuit 144 is opened to a port dand a port, respectively.The first governor valve 11 3 and the second governor valve 114 operate the 1-2 shift valve 131 and the 2-3 shift valve 1 32 by a governor pressure produced at the forward drive running so as to effect the automatic gear shifting function and also to control the line pressure. When the manual valve 130 is either in the D, II or I position, the hydraulic pressure is fed from the line pressure circuit 144 via a port c of the manual valve 1 30 to the second governor valve 114. If the vehicle runs, the governor pressure adjusted by the second governor valve 114 is passed to a circuit 1 57 and introduced into the first governor valve 113.When the vehicle speed reaches a certain value, the spool 1 77 of the first governor valve 11 3 moves to connect the circuit 1 57 with a circuit 1 58 and a governor pressure is produced.
This governor pressure fed through the circuit
158 acts against one end surface of the 1-2 shift valve 131, the 2-3 shift valve 132, and the pressure modifier valve 1 34 respectively, to balance with a respective bias force caused by respective spring and force caused by hydraulic pressure pressing each of the valves towards right. The 1-2 shift valve 131 and the second lock valve 135 are separately provided between the hydraulic oil circuit starting from the port c of the manual valve 130 and via the circuit 18, the circuit 161 and the circuit 11 and leading to a servo applying chamber 3b of a band servo 141 for applying the second brake 106. Further there is provided with a circuit 1 52 leading from the port b of the manual valve 130 to the second lock valve 135.
Accordingly, if the select lever is set at the D position, the spool 1 50 of the manual valve 130 is moved so that the line pressure circuit 144 is coupled to the ports a, b and c, respectively. From the port a, the hydraulic pressure passes through the circuit 151 and a part thereof acts at bottom side of the second lock valve 1 35. This pressure pushes up the second lock valve 1 35 in order that the circuit 161 now conducted to the circuit 11 will not be interrupted by the spool 1 78, which is biassed upwardly by a spring 1 79 and depressed downwardly by the hydraulic pressure applied through the port b. Another part of the hydraulic pressure coming from the port a reaches the 2-3 shift valve t32 via an orifice 1 66 and a circuit
1 67.Further from the port c, the pressure is applied through a circuit 1 8 to the second governor valve 114, rear clutch 2 and to the 1-2 shift valve 1 31 so that the automatic transmission system assumes the forward first speed drive condition. In this condition, if the vehicle speed reaches a certain value, by the governor pressure acting on the circuit 158, the spool 1 60 of the 1-2 shift valve 1 31, the spool
160, which is pressed towards right by the spring 1 tri9, is now moved leftwards so as to effect an automatic shift operation from the forward first speed range to the forward second speed range.
By the above movement, the circuit 1 8 is connected to the circuit 161 and the hydraulic pressure is fed through the second lock valve 135 and the circuit 11 to the servo applying chamber 3b of the servo cylinder 3 to apply the second brake 106 and the transmission system changes to a condition of forward second speed range.
When the vehicle speed further increases and it reaches a certain predetermined speed, the governor pressure of the circuit 1 58 overcomes the spring force of the spring 1 63 so the spool
164 of the 2-3 shift valve 132 is pressed Ieftwards and the circuit 1 67 is connected to the circuit 7. From the circuit 7, the hydraulic pressure is in one part delivered to the servo release chamber 3b of the servo cylinder 3 so as to release the second brake 106. The other part of the hydraulic pressure is delivered to the front clutch 1 so as to couple it so that the transmission system moves into the third speed condition.
When the select lever is set at the II position (forward second fixed speed), the spool 150 of the manual valve 130 is moved to couple the line pressure circuit 144 to the ports b, c and d. The hydraulic pressure is passed from the ports b andc just as in the case of the D position and the rear clutch 2 is coupled.On the other hand, since at the bottom side of the second lock valve 135 there is no hydraulic pressure in this II position, and since the spool 1 78 has wider land area at the bottom side compared with the land area of its upper side open to the circuit 1 52 and being applied with the hydraulic pressure, the spool 178 of the second lock valve 135 is pressed down against the force of the spring 1 79. By this, the circuit 1 52 is connected to the circuit 11 and the hydraulic oil pressure reaches the servo applying chamber 3b of the servo cylinder 3 so that the second brake 106 is applied and the transmission system now moves into the forward second speed range.The hydraulic oil pressure passes, from the port d, the circuit 154 and reaches the solenoid downshift valve 137 and the throttle back up valve 138. The port a of the manual valve 130 is isolated from the line pressure circuit 144. Also as the hydraulic oil pressure in the circuit 151 is not applied to the 2-3 shift valve 132, the release of the second brake 106 and coupling of the front clutch 1 are not effected. Thus the transmission system will not move into the forward third speed range. The second lock valve 135 has a function together with the manual valve 1 30 to maintain the transmission system in the forward second speed range.
When the select lever is set at the I position (forward fixed first speed), the line pressure circuit 144 is coupled to the ports c, d and e. The hydraulic pressure from the ports c and dare delivered to the same locations as in the case of the II position so the rear clutch 2 is coupled.
From the port e, the hydraulic oil pressure passes through the circuit 155, the 1-2 shift valve 131 and the circuit 19 and reaches on the one hand to the low-and-reverse brake 4 to apply this brake functioning as a forward reaction brake to put the transmission system in the forward first speed range, and on the other hand reaches the left hand side of 1-2 shift valve 131 and presses the spool 160 towards the right together with the spring 1 59 to maintain the forward first speed condition.
With the select lever in the R position (reverse running), the spool 150 is moved accordingly and the line pressure circuit 144 is connected to the ports d, e and f.
The hydraulic pressure from the port e passes through the circuit 1 55 and is delivered to the circuit 19 and acts to couple the low-and-reverse brake 4. Further the hydraulic pressure from the port fpasses through the 2-3 shift valve 132 to
reach the circuit 7 and eventually to the servo
release chamber 3a of the servo cylinder 3 and
acts to release the second brake 106 and also to couple the front clutch 1 to obtain the reverse running.
According to the present invention, a shock reducing arrangement to be described hereinafter with reference to Figs. 3 to 6 is incorporated in the controlling system to reduce the select shock at the time of changing the manual valve from the
N range to the D range or to the R range, as well as the shift shock at the time of the upshifting.
In these figures, reference numeral 1 denotes the front clutch, 2 the rear clutch, 3 the servo cylinder for causing engagement and disengagement of the second brake, and 4 the low-and-reverse brake. As in the conventional automatic transmission, the front clutch 1 is connected via a passage 6 having a restriction 5 therein, to a passage 7 which is connected at one end to a servo release chamber 3a of the servo cylinder 3 via a restriction 8, and at its other end to a corresponding port of the manual valve via the 2-3 shift valve. The servo apply chamber 3b of the servo cylinder 3 is connected, via a passage 11 including a check valve 9 and a restriction 10 connected in parallel to each other, and via the 1-2 shift valve, to the corresponding port of the manual valve.Within the passage 6 is disposed a shuttle valve 12 through which the passage 6 is connected to one end of the passage 13 whose other end, in turn, is connected, via a check valve 14 and a restriction which are connected in parallel to each other, to the corresponding port of the manual valve. The rear clutch 2 is connected, via a passage 18 including therein a check valve 16 and a restriction 17 which are connected in parallel to each other, to the corresponding port of the manual valve. The low-and-reverse brake 4 is connected, via the passage 19 to the corresponding port of the manual valve.
Reference numeral 20 denotes an accumulator to be used in conjunction with the device according to the invention, formed therein with a cylinder bore 21 having a small diameter and with a cylinder bore 22 having a large diameter and disposed in adjacent relationship with the bore 21. A stepped piston 23 slidably arranged within the bores 21, 22 is urged upwardly as viewed in the figure by means of a spring 24, and defines a chamber 25 to which faces the end surface of the small diameter portion 23a of the piston 23, a chamber 26 to which faces the end surface of the large diameter portion 23b, and a chamber 27 disposed between both portions 23a, 23b.
According to one embodiment of the present invention shown in Fig. 3, portion of the passage
13 between the shuttle valve 12 and the check valve 14 is connected, by means of a passage 28.
to the chamber 25, while the portion of the passage 11 between the servo apply chamber 3b and the check valve 9 is connected to the chamber 26, and the portion of the passage 18 between the rear clutch 2 and the check valve 16 is connected to the chamber 27.
Operation of the above described embodiment is as follows:
When a driver changes the manual valve from the N range to the D range by the control lever, the line pressure normally applied to the manual valve is supplied to the rear clutch 2 via the passage 1 8 and the restriction 1 7 therein at a speed dependant upon the area of the restriction 1 7 to cause engagement of the clutch 2. Thus, the vehicle is now allowed to run forwardly. At this time, the line pressure supplied to the rear clutch 2 reaches the chamber 27 of the accumulator 20 displacing the piston 23 downwardly against the spring 24 with a force which equals the value of the line pressure multiplied by the differential area of the upper surface of the large diameter portion 23b and the lower surface of the small diameter portion 23a of the piston.The line pressure to the rear clutch 2 being restricted by the restriction 1 7 is initially low, and gradually increases up to the normal line pressure. During this, when the pressure to the rear clutch 2 reaches a pre-determined value prevailing due to the force exerted by the spring 24, this pressure causes the piston 23 to displace downwardly against the spring 24. However, the pressure to the rear clutch 2 is kept in equilibrium with the upward force exerted by the spring 24.
Accordingly, during movement of the piston 23, the pressure to the rear clutch 2 increases at a relatively slow rate. In this manner, the accumulator 20 reduces the select shock which takes place when the manual valve is changed from the N range to the D range.
After starting the vehicle, when the speed thereof reaches a pre-determined value, the line pressure from the manual valve 130 is supplied, via the 1-2 shift valve 1 31 responsive to the governor pressure corresponding to the vehicle speed, and via the restriction 10 within the passage 11, to the servo apply chamber 3b of the servo cylinder 3 so as to actuate the second brake. Operation of this second brake, in conjunction with the engagement of the rear clutch 2 by holding the manual valve in the D range, results in an automatic upshift from the first speed range to the second speed range.
During this, the pressure supplied to the servo apply chamber 3b reaches the chamber 26 as well, acting on the lower end surface of the large diameter portion 23b of the piston 23 to displace the piston 23 upwardly from its lower position.
Since the line pressure is restricted by the restriction 10, the pressure supplied to the servo apply chamber 3b is initially low, and gradually increases up to the line pressure. When the pressure supplied to the servo apply chamber 3b reaches a pre-determined value such that the upwardly acting force resulting from this pressure acting on the lower end surface of the large diameter portion 23b and from the spring 24 cooperating therewith prevails the downwardly acting force by the line pressure acting on the differential area of the upper end surface of the large diameter portion 23b and the lower end surface of the small diameter portion 23a, the piston 23 which was lowered at the time of reducing the select shock as stated is now returned to its upper position.By this return movement, the accumulator 20 gradually increases the pressure supplied to.the servo apply chamber 3b so as to reduce the shift shock during the upshifting from the first speed to the second speed. Considering now the operational characteristics of the accumulator 20, the upward return movement of the piston 23 is effected against the line pressure supplied to the chamber 27 which line pressure increases proportionally to the throttle opening as being controlled by the throttle pressure corresponding to the throttle opening. Accordingly, the threshold value of the pressure in the chamber 26 (corresponding to the pressure supplied to the servo apply chamber 3b) to initiate operation or upward movement of the piston 23 of the accumulator 20 can be increased in proportion to the throttle opening as shown in
Fig. 6 by line a-b.In this manner, according to the present embodiment, the shift shock during upshifting from the first to the second speed can be positively reduced irrespective of the throttle opening and without accompanying slip in the second brake or sudden engagement thereof.
Upon a further increase of the vehicle speed, the passage 7 is supplied with the line pressure from the manual valve through the 2-3 shift valve responsive to the governor pressure corresponding to this speed. The line pressure is further supplied on one hand to the front clutch 1 through the restriction 5 and the shuttle valve 12, and on the other hand to the servo release chamber 3a through the orifice 8. The line pressure after the restriction 5 urges the valve element or ball 1 2a of the shuttle valve 12 to the position in which the passage 1 3 is disconnected from the passage 6. Thus the passage 6 is now supplied with the line pressure so that the front clutch 1 is positively engaged.Further, the line pressure supplied to the clutch release chamber 3a acts on the differential area of the servo piston for the servo cylinder 3 and in conjunction with the force of the associated return spring displaces the servo piston to its non-operative position so as to disengage the second brake. By the engagement of the front clutch 1 in conjunction with the disengagement of the second brake, the transmission is automatically upshifted from the second to the third speed since, as stated above, the rear clutch 2 is kept in engagement. Although the shock reducing arrangement according to the invention is not operative during this upshifting, undesirable shift shock is practically not produced as the reduction ratio for the third speed, i.e., the shaft torque is small.
When the driver changes the manual valve from the N range to the R range, the line pressure normally supplied to the manual valve is delivered through the restriction 15, the passage 13 and the shuttle valve 12 to the front clutch 1. The line pressure supplied to the passage 1 3 displaces the ball 1 2a of the shuttle valve 12 towards the left to close the passage 6, so that the line pressure is supplied positively to the front clutch 1 to cause engagement thereof. At the same time, the line pressure from the manual valve is supplied via the passage 1 9 to the low-and-reverse brake 4 to make the same operative. Accordingly, with the front clutch 1 in engagement and the low-andreverse brake 4 in operation, the automatic transmission now moves the vehicle in reverse.In this condition, the pressure supplied to the front clutch 1 is delivered via the passage 28 to the chamber 25 and acts on the upper end surface of the small diameter portion 23a of the piston 23 tending to displace the piston 23 downwardly against the spring 24. However, since the pressure supplied to the front clutch 1 is the line pressure restricted by the restriction 15, the pressure has initially the low value, and then increases gradually up to the unrestricted line pressure level. Only after the pressure to the front clutch 1 reaches a pre-determined value by which the pressure prevails the spring 24, the pressure is then kept in equilibrium with the upwardly acting force of the spring 24 so that the pressure increases at a relatively slow rate during the displacement of the piston 23.By this displacement of the piston 23, the accumulator 20 causes the pressure to the front clutch 1 to increase gradually so that the select shock during the change of the manual valve from the N range to the R range is reduced.
Fig. 4 shows another embodiment of the invention wherein the portion of the passage 1 3 between the shuttle valve 12 and the check valve
14 is not directly connected to the chamber 25, but firstly to the rear clutch 2 through the passage 29 which is branched to the passage 30 connected to the chamber 25. Further, at the junction of the passages 29, 30 is disposed a shuttle valve 31 which acts such that when the line pressure is delivered to the passage 13, the pressure urges the ball 31 a to connect the passages 13 and 30 with each other, whereas when the line pressure is delivered to the passage
18, this pressure urges the ball 31 a to connect the passages 18 and 30 with each other.
With this arrangement, select shock during the change of the manual valve from the N range to the D range can be reduced as in the previous
embodiment. Further, when the manual valve is
changed from the N range to the R range, the line
pressure is delivered to the passage 1 3 urging the
ball 31 a of the shuttle valve 31 upward and
reaches the chamber 25 through the passage 30
so that in this case, too, the select shock is
reduced. During the automatic upshifting from the
first to the second speed, however, the line
pressure acting in the passage 1 8 urges the ball
31 a downward and is delivered through the
passage 30 to the chamber 25.Accordingly, the
line pressure supplied to the chamber 25 acts on the upper end surface of the small diameter
portion 23a generating a force which displaces
the piston 23 downwardly against the spring 24.
This force is added to the downward force acting
on the piston 23 by the line pressure applied to
the chamber 27 as in the previous embodiment.
In this manner, during the upshifting from the first to the second speed, the threshold value of the pressure to initiate operation of the accumulator 20 (that value of the servo apply pressure supplied to the chamber 26 by which the servo apply pressure begins to return the piston 23) can be increased as shown in Fig. 6 by the line c-d in comparison to the value according to the previous embodiment. In this case, too, the pressure supplied to the chambers 25, 27 is the line pressure which increases as the throttle opening increases Accordingly, the threshold pressure value of the accumulator increases in proportion to the throttle opening permitting reduction of the shift shock.
Fig. 5 shows a further embodiment of the invention wherein provision is made of a valve 32 for changing connection of the passages. This valve 32 comprises a spool 33 having one end surface on which acts the pressure within the passage 1 3 and supplied through the passage 34 in conjunction with the spring 35, and the other end surface on which acts the throttle pressure from the throttle valve and supplied through the passage 36. The spool 33 in the lower position shown connects the ports 37 and 38 with each other, and in the upper position connects the ports 37 and 39 with each other. The ports 37, 38, 39 are connected to the chamber 25 and to the passages 1 8, 1 9, respectively.
With this arrangement, when the manual valve is changed from the N range to the D range, the throttle pressure supplied through the passage 36 and acting on one of the end surfaces of the spool
is zero since the accelator pedal is not depressed.
Accordingly, the spool 33 is kept by the spring 35
in its lower position shown closing the port 39 while connecting the ports 37, 38 with each other Thus, the pressure from the passage 1 8 reaches the port 39 and is blocked here, and since the passage 13 communicates with the chamber 25 via the ports 38, 37 and the passage 13 is
drained in the D range, the chamber 25 is drained.
When the manual valve is changed from the N
range to the R range, the pressure generated in
the passage 13 is delivered through the passage
34 and acts on the upper end surface of the spool
33 to keep the spool 33 in its lower position
shown in conjunction with the spring, thereby
closing the port 39 and connecting the ports 37,
38 with each other. Accordingly, the pressure in
the passage 13 is supplied via the ports 38, 37 to
the chamber 25 so that the select shock during
the change of the manual valve from the N range
to the R range is reduced in the same manner as
stated with reference to the embodiment of Fig. 3.
On the other hand, the shift shock during the
sutomatic upshifting from the first to the second
speed is reduced in the following manner.
Namely, when the throttle opening is small during
this upshifting, the throttle pressure from the
passage 36 acting on the end surface of the spool
33 is not sufficiently high to cause the upward
movement of the spool 33 to establish
connection between the ports 37 and 39 so that
the port 37 is kept in communication with the port 38. Thus, the hydraulic circuit similar to that shown in Fig. 3 is formed, and the operational characteristic of the accumulator will be as shown in Fig. 6 by the line a-c, with the throttle opening no less than a predetermined value f (Fig. 6) during this upshifting, a correspondingly high throttle pressure is supplied via the passage 36 and acts on the end surface of the spool 33 to upwardly displace the spool. The port 37 is then disconnected from the port 38 and connected to the port 39.Thus, as long as the manual valve is kept in the D range, the line pressure to the rear clutch 2 and generated in the passage 1 8 is supplied via the ports 39, 37 to the chamber 25 so that a hydraulic circuit is formed which is similar to that shown in Fig. 4, and the operational characteristic will be as shown in Fig. 6 by the line g-d. This means that the characteristic of the threshold pressure for the accumulator will be the line a-e-g-d as shown in Fig. 6, and the shift shock can be positively reduced by varying the threshold pressure between the low throttle opening and the high throttle opening.
According to the present invention, a single accumulator serves to reduce the select shock during the change of the manual valve from the N range to the D range or to the R range, and the shift shock during the automatic upshifting from the first to the second speed. Furthermore, the threshold pressure to initiate the operation of the accumulator can be increased in proportion to the throttle opening so that irrespective of the throttle opening, the shift shock is reduced without accompanying undesirable slip of the second brake.
Claims (23)
1. An automatic power transmission having an automatic forward drive range condition, a reverse drive gear condition and at least two gear ratios in the automatic forward drive range condition and including a transmission mechanism having incorporated therein a fluid operated first frictional unit contributive to the selection of said reverse drive gear position, a fluid operated second frictional unit contributive to shifting from one of said gear ratios to the other and a fluid operated third frictional unit contributive to the selection of said automatic forward range condition, and a hydraulic control system including first control pressure generating means for producing a first control fluid pressure variable with engine load and second control pressure generating means for producing a second control fluid pressure variable with and not lower than said first control fluid pressure, a shock control arrangement for reducing shocks to be produced during selection of any of said automatic forward drive range conditions and said reverse drive range condition or during shifting between said gear ratios, wherein the arrangement comprises: a pressure accumulator unit operatively positioned between said second control pressure generating means and each of the first, second and third frictional units and including a fluid operated piston having a first pressure acting area to be acted upon by a fluid pressure and to urge the piston to move in a first direction when said first frictional unit is to be actuated, a second pressure acting area to be acted upon by a fluid pressure and to urge the piston to move in a second direction opposite to said first direction when said second frictional unit is to be actuated and a third pressure acting area to be acted upon by a fluid pressure for urging the piston to move in said first direction when said third frictional unit is to be actuated, and resilient biasing means for urging said piston to move in said second direction; and hydraulic fluid circuit means for directing said second control fluid pressure selectively to said first, second and third frictional units.
2. A shock control arrangement as claimed in claim 1, wherein said circuit means comprises first passageway means communicable with said first frictional unit and constantly open to said first pressure acting area, second passageway means constantly communicating with said second frictional unit and constantly open to said second pressure acting area and third passageway means constantly communicating with said third frictional unit and constantly open to said third pressure acting area.
3. A shock control arrangement as claimed in claim 1, wherein said circuit means comprises first passageway means communicable with said first frictional unit, second passageway means constantly communicating with said second frictional unit and constantly open to said second pressure acting area, third passageway means constantly communicating with said third frictional unit and constantly open to said third pressure acting area, and means, provided between the first and third passageway means and constantly open to said first pressure acting area, for opening said first passageway means to said first pressure acting area in the presence of a fluid pressure in the first passageway means and for opening said third passageway means to said first pressure acting area in the presence of a fluid pressure in the third passageway means so that said third passageway means is open to not only said third pressure acting area but said first pressure acting area in the presence of a fluid pressure in the third passageway means.
4. A shock control arrangement as claimed in claim 1, wherein said circuit means comprises first passageway means communicable with said first frictional unit, second passageway means constantly communicating with said second frictional unit and constantly open to said second pressure acting area, third passageway means constantly communicating with said third frictional unit and constantly open to said third pressure acting area, and means, provided between the first and third passageway means and constantly open to said first pressure acting area, for opening said first passageway means to said first pressure acting area through said opening means when said first control fluid pressure is lower than a- predetermined value and for opening said first pressure acting area through said opening means when said first control fluid pressure is higher than said predetermined value so that said third passageway means is open to not only said third pressure acting area but to said first pressure acting area when the first control fluid pressure is higher than said predetermined value, said first control fluid pressure means being coupled for communication with said opening means.
5. A shock control arrangement as claimed in claim 4, wherein said opening means comprises a valve element having a first pressure acting area to be acted upon by a fluid pressure in said first passageway means for urging the valve element to move in a first direction and permitting said first passageway means to be open to said first pressure acting area of said pressure accumulator unit and a second pressure acting area to be acted upon by said first control fluid pressure for urging said valve element to move in a second direction opposite to said first direction and permitting said third passageway means to be open to said first pressure acting area of said pressure accumulator unit through said opening means, and resilient biasing means urging said valve element to move in said first direction thereof with a substantially constant force which is to be overcome by the force resulting from the first control fluid pressure acting on said second pressure acting area of said valve element when the first control fluid pressure is higher than said predetermined value.
6. A shock control arrangement as claimed in any one of claims 2 to 5, wherein said circuit means further comprises one-way flow restriction means in at least one of the first, second and third passageway means, said restriction means being arranged operatively between said pressure accumulator unit and said first control pressure operating means.
7. An automatic transmission for an automotive vehicle, the transmission comprising:
a first frictional unit;
a second frictional unit:
a third frictional unit;
a source of first fluid pressure variable with an operating condition of the vehicle;
a source of second fluid pressure, which is not lower than said first pressure, for actuating said first, second and third frictional units;
a pressure accumulator unit including a cavity, a fluid operated piston movable within said cavity, said cavity and piston defining a first expansible chamber, a second expansible chamber and a third expansible chamber, said piston being movable in response to pressurization of one of said first, second or third chambers, in such a manner as to increase the volume of said one chamber;
a first passageway extending between said source of second pressure and said first frictional unit;;
a second passageway extending between said source of second pressure and said second frictional unit;
a third passageway extending between said source of second pressure and said third frictional unit;
means for establishing communication between said first chamber of said pressure accumulator unit and said first passageway, for establishing communication between said second chamber of said pressure accumulator unit and said second passageway, and for establishing communication between said third chamber of said pressure accumulator unit and said third passageway.
8. An automatic power transmission as claimed in claim 7, wherein said piston is urged in a first direction when said first and/or said third chamber is pressurized and wherein said pressure accumulator unit includes a spring, coupled with said piston, for biasing said piston in a second direction opposite to said first direction.
9. An automatic transmission as claimed in claim 8, wherein said piston is urged in said second direction when said second chambers pressurized.
10. An automatic power transmission as claimed in claim 7, wherein said establishing means includes a means for switching communication between, on the one hand, said first chamber of said pressure accumulator unit and said first passageway and, on the other hand, said first chamber of said pressure accumulator unit and said third passageway.
11. An automatic power transmission as claimed in claim 10, wherein said switching means establishes communication between said first chamber of said pressure accumulator unit and said first passageway when said first passageway is pressurized, and said switching means establishes communication between said first chamber of said pressure accumulator unit and said third passageway when said third passageway is pressurized.
12. An automatic power transmission as claimed in claim 10, wherein said switching means is coupled for communication with said source of first pressure, said switching means including a valve with a movable valve element having a pressure acting area on which said first fluid pressure acts to move said valve element to establish communication between said first chamber of said pressure accumulator unit and said first passageway when said first fluid pressure is lower than a predetermined value and to establish communication between said first chamber of said pressure accumulator unit and said third passageway when said first fluid pressure is higher than said pre-determined value.
13. An automatic transmission having an automatic forward drive range condition, a reverse drive gear condition and at least two gear ratios in the automatic forward drive range condition, the transmission comprising:
a fluid operated first frictional unit;
a fluid operated second frictional unit;
a fluid operated third frictional unit;
a source of fluid pressure;
a manual selector communicating with said source of fluid pressure;
a first conduit structure connecting said first frictional unit to said manual selector;
a second conduit structure connecting said second frictional unit to said manual selector;
a shift valve partly defining said second conduit structure;
a third conduit structure connecting said third frictional unit to said manual selector;;
a pressure accumulator unit including a fluid operated piston which includes a first pressure acting area communicating with said second conduit structure at a location between said shift valve and said second frictional unit, and a third pressure acting area communicating with said third conduit structure; said pressure accumulator unit including resilient biasing means acting on said fluid operated piston.
14. An automatic transmission as claimed in claim 13, wherein said second pressure acting area of said fluid operated piston is larger than said first pressure acting area and larger than said third pressure acting area.
1 5. An automatic transmission as claimed in claim 14, wherein said second pressure acting area and said resilient biasing means are mutually so disposed that the force acting on said piston at said second pressure acting area is directed in a direction assisting the force of said resilient biasing means, and wherein said first and third pressure acting areas are so disposed with respect to each other and with respect to said second pressure acting area and said resilient biasing means that the force acting on said piston at said first and third pressure acting areas is directed oppositely to the force of said resilient biasing means.
1 6. A shock control arrangement in a hydraulic control system for an automatic transmission having a plurality of frictional units operated by fluid actuators for effecting shifting between gear ratios and operational modes of the transmission, the transmission including a source of pressurized fluid which supplies pressurized fluid to the fluid actuators to operate the friction units, the shock control arrangement comprising::
a single unitary hydraulic accumulator having first, second and third expansible fluid chambers therewithin;
first means, coupled with said accumulator and communicating with said first expansible chamber thereof, for effecting communication both with the pressure source and with the fluid actuator of one of the frictional units;
second means, coupled with said accumulator and communicating with said second expansible chamber thereof, for effecting communication both with the pressure source and with the actuator of another frictional unit;
third means, coupled with said hydraulic accumulator and communicating with said third expansible chamber thereof, for effecting communication with said fluid source and with the actuator of a frictional unit different from both the one and the other frictional units;;
whereby the unitary accumulator reduces shocks during shifting actions effected by three separate frictional units of the transmission by expansion of each chamber at the time of shifting of its associated frictional unit to temporarily reduce the pressure of the fluid fed to the actuator of the associated frictional unit.
1 7. A shock control arrangement as claimed in claim 16, wherein said accumulator includes a wall portion defining an interior cavity and a single, unitary, movable piston within said cavity, said piston and said wall portion together defining said first, second and third expansible chambers, said piston being movable in a first direction in response to pressurization of said first and/or third expansible chambers and in a second direction, opposite to said first direction, in response to pressurization of said second expansible chamber.
18. A shock control arrangement as claimed in claim 17, further including means for maintaining pressurization of said third expansible chamber when said expansible chamber is pressurized, said maintaining means including said third communication effecting means.
19. A shock control arrangement as claimed in claim 18, wherein said accumulator includes means for resisting movement of said piston in said first direction and means for resisting movement of said piston in said second direction, said first direction resisting means including a compression spring between said piston and said wall portion of said accumulator, said second direction resisting means including said third pressure acting area of said piston and said maintaining means.
20. A shock control arrangement as claimed in claim 17, wherein said piston includes a body portion with a central axis, a first flange extending outwardly from said body portion and a second flange axially spaced from said first flange to define a segment of said body portion extending between said first and second flanges, said second flange also extending outwardly from said body portion, said second flange being disposed a greater distance outwardly from the axis of the body portion than said first flange;
said cavity having an axis corresponding generally with the axis of said body portion of said piston, said cavity including a first portion and a second portion, said second portion extending outwardly of said first portion;;
said first chamber being at least partially defined by said first flange and said first cavity portion, said second expansible chamber being at least partially defined by said second cavity portion and said second flange, said third chamber being defined by said first or second chamber portions or both, depending on the position of the piston, by said first and second flanges, and by said segment of said body portion extending between the space between the first and second flanges, said segment partially de limiting said second expansible chamber in all positions of the piston.
21. A shock control arrangement as claimed in claim 20, wherein said first flange has a seal therein which engages said first cavity portion and circumscribes an area, and wherein said second flange has a second seal therein which engages said second cavity portion and circumscribes another area.
22. A shock control arrangement as claimed in claim 21, wherein said piston includes a first pressure acting area adjacent one end of the piston and partially defined by said first flange, a second pressure acting area adjacent the other end of the piston, said second pressure acting area being at least partially defined by said second flange, and a third effective pressure acting area intermediate the ends of the piston, said third pressure acting area being defined by the difference between the area circumscribed by the first seal and the area circumscribed by the second seal, said second pressure acting area being greater than said first pressure acting area, said second pressure acting area also being greater than said third pressure acting area.
23. A shock control arrangement as claimed in claim 20, wherein said body portion of said piston has a frusto-conical configuration in which the body portion diverges outwardly from its axis in a direction from said first flange toward said second flange.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9591978A JPS5945862B2 (en) | 1978-08-07 | 1978-08-07 | Automatic transmission shock reduction device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2028937A true GB2028937A (en) | 1980-03-12 |
| GB2028937B GB2028937B (en) | 1983-02-16 |
Family
ID=14150677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7927404A Expired GB2028937B (en) | 1978-08-07 | 1979-08-07 | Shock control arrangement in hydraulic control system of automatic power transmission |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5945862B2 (en) |
| DE (1) | DE2931828C2 (en) |
| FR (1) | FR2433138A1 (en) |
| GB (1) | GB2028937B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0118003A2 (en) * | 1983-02-02 | 1984-09-12 | Nissan Motor Co., Ltd. | Transmission control system including select shock suppressing arrangement |
| EP0133184A1 (en) * | 1983-07-29 | 1985-02-20 | Nissan Motor Co., Ltd. | Hydraulic control system for automatic transmission |
| US4539870A (en) * | 1983-07-29 | 1985-09-10 | Nissan Motor Co., Ltd. | Hydraulic control system for automatic transmission |
| EP0190556A2 (en) * | 1985-01-09 | 1986-08-13 | Nissan Motor Co., Ltd. | Shift shock suppression arrangement for automotive automatic transmission |
| EP0307511A1 (en) * | 1982-08-20 | 1989-03-22 | Nissan Motor Co., Ltd. | Automatic transmission |
| EP0564363A1 (en) * | 1992-04-03 | 1993-10-06 | Regie Nationale Des Usines Renault S.A. | Universal control device for consumers in automatic gearboxes |
| EP0629797A1 (en) * | 1993-06-21 | 1994-12-21 | General Motors Corporation | Hydraulic control system for a transmission |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5948902B2 (en) * | 1978-08-30 | 1984-11-29 | 日産自動車株式会社 | Automatic transmission shock reduction device |
| JPS59166750A (en) * | 1983-03-11 | 1984-09-20 | Honda Motor Co Ltd | Control unit of hydraulic operating type transmission for vehicle |
| JPH0674846B2 (en) * | 1983-12-30 | 1994-09-21 | アイシン・エィ・ダブリュ株式会社 | Control device for automatic transmission for vehicle |
| JPS60143253A (en) * | 1983-12-30 | 1985-07-29 | Aisin Warner Ltd | Controller for automatic transmission gear for vehicle |
| JPS60146947A (en) * | 1983-12-30 | 1985-08-02 | Aisin Warner Ltd | Control device of automatic speed change gear for car |
| JPS60143254A (en) * | 1983-12-30 | 1985-07-29 | Aisin Warner Ltd | Controller for automatic transmission gear for vehicle |
| JPS60143259A (en) * | 1983-12-30 | 1985-07-29 | Aisin Warner Ltd | Controller for automatic transmission gear for vehicle |
| JPS60143261A (en) * | 1983-12-30 | 1985-07-29 | Aisin Warner Ltd | Controller for automatic transmission gear for vehicle |
| JPS60146950A (en) * | 1983-12-30 | 1985-08-02 | Aisin Warner Ltd | Controller for automatic speed changer of car |
| JPS60146946A (en) * | 1983-12-30 | 1985-08-02 | Aisin Warner Ltd | Control unit of automatic speed change gear for car |
| JPS60143262A (en) * | 1983-12-30 | 1985-07-29 | Aisin Warner Ltd | Controller for automatic transmission gear for vehicle |
| DE3712547A1 (en) * | 1986-04-22 | 1987-10-29 | Volkswagen Ag | Hydraulic control device |
| JP2759945B2 (en) * | 1987-10-16 | 1998-05-28 | 日産自動車株式会社 | Selective shock reduction device for automatic transmission |
| JP2767366B2 (en) * | 1993-08-30 | 1998-06-18 | 本田技研工業株式会社 | Control device for hydraulically operated transmission for vehicles |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB937699A (en) * | 1961-02-20 | 1963-09-25 | Gen Motors Corp | Control system for a motor vehicle change-speed transmission |
| US3631744A (en) * | 1969-12-22 | 1972-01-04 | Chrysler Corp | Hydrodynamic transmission |
| JPS4820654B1 (en) * | 1970-02-12 | 1973-06-22 | ||
| US3714849A (en) * | 1970-12-21 | 1973-02-06 | Borg Warner | Automotive transmission |
| US3799308A (en) * | 1972-10-20 | 1974-03-26 | Int Harvester Co | Transmission clutches with feedback controlled pressure modulator |
| DE2334195C2 (en) * | 1973-07-05 | 1983-03-24 | Gebr.Claas Maschinenfabrik GmbH, 4834 Harsewinkel | Control device for transmissions of self-propelled machines, in particular combine harvesters |
| DD114930A1 (en) * | 1974-08-26 | 1975-09-05 | ||
| JPS5174168A (en) * | 1974-12-23 | 1976-06-26 | Toyota Motor Co Ltd | Jidohensokukino yuatsuseigyosochi |
| US3988951A (en) * | 1975-03-12 | 1976-11-02 | General Motors Corporation | Four wheel drive transmission |
| US3995727A (en) * | 1975-07-14 | 1976-12-07 | Borg-Warner Corporation | Automatic lubricant flow increase valve |
-
1978
- 1978-08-07 JP JP9591978A patent/JPS5945862B2/en not_active Expired
-
1979
- 1979-08-06 FR FR7920099A patent/FR2433138A1/en active Granted
- 1979-08-06 DE DE19792931828 patent/DE2931828C2/en not_active Expired
- 1979-08-07 GB GB7927404A patent/GB2028937B/en not_active Expired
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0307511A1 (en) * | 1982-08-20 | 1989-03-22 | Nissan Motor Co., Ltd. | Automatic transmission |
| EP0118003A2 (en) * | 1983-02-02 | 1984-09-12 | Nissan Motor Co., Ltd. | Transmission control system including select shock suppressing arrangement |
| EP0118003A3 (en) * | 1983-02-02 | 1985-08-28 | Nissan Motor Co., Ltd. | Transmission control system including select shock suppressing arrangement |
| EP0133184A1 (en) * | 1983-07-29 | 1985-02-20 | Nissan Motor Co., Ltd. | Hydraulic control system for automatic transmission |
| US4539870A (en) * | 1983-07-29 | 1985-09-10 | Nissan Motor Co., Ltd. | Hydraulic control system for automatic transmission |
| EP0190556A2 (en) * | 1985-01-09 | 1986-08-13 | Nissan Motor Co., Ltd. | Shift shock suppression arrangement for automotive automatic transmission |
| EP0190556A3 (en) * | 1985-01-09 | 1987-03-11 | Nissan Motor Co., Ltd. | Shift shock suppression arrangement for automotive automatic transmission |
| US4729265A (en) * | 1985-01-09 | 1988-03-08 | Nissan Motor Co., Ltd. | Shift shock suppression arrangement for automotive automatic transmission |
| EP0564363A1 (en) * | 1992-04-03 | 1993-10-06 | Regie Nationale Des Usines Renault S.A. | Universal control device for consumers in automatic gearboxes |
| FR2689595A1 (en) * | 1992-04-03 | 1993-10-08 | Renault | Universal automatic receiver receiver control device. |
| EP0629797A1 (en) * | 1993-06-21 | 1994-12-21 | General Motors Corporation | Hydraulic control system for a transmission |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2931828A1 (en) | 1980-03-06 |
| JPS5945862B2 (en) | 1984-11-09 |
| DE2931828C2 (en) | 1985-08-14 |
| GB2028937B (en) | 1983-02-16 |
| JPS5524222A (en) | 1980-02-21 |
| FR2433138A1 (en) | 1980-03-07 |
| FR2433138B1 (en) | 1984-04-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19920807 |