DE3339880A1 - Hydraulic control device for the shift elements of power shift transmissions - Google Patents

Abstract

The invention relates to a hydraulic control device for power shift transmissions, especially for automatic transmissions of motor vehicles. A pressure line can be connected by way of a selector slide valve (23) to a main pressure line in which a pressure medium source (17) delivers pressure medium for the actuation of shift elements, such as clutches A to D or the like. Two pressure control valves (31, 32) with proportional pressure characteristic are connected to the main pressure line (36) by way of a shuttle valve (28) for shifting of the gears. In addition two solenoid valves (67, 71) are provided, which together with a reversing valve (65) undertake the actuation of three shift valves (34, 40, 73) for determining the individual gears. With the two pressure control valves the individual shifts can be undertaken with overlap control and the one-way clutches in the transmission can be omitted without thereby having to sacrifice the greatest possible degree of safety. Constant engaging of a plurality of gears or a gear shift in which the shift element to be released remains under full system pressure is not possible. <IMAGE>

Description

Hydraulic control device for the switching

elements of powershift transmissions State of the art The invention works from a Regeieeinriflhtung according to the genre of the main claim. With such a known control device can each of the five switching elements of a three-speed Automatic transmission acted upon with its own electromagnetic pressure regulator will. In this case, emergency operation is activated if the electronic control system fails by an additional, manually operated control of the pressure regulator or via allows two additional solenoid valves. A hydraulic lock against incorrect control of pressure regulators, what. 3. to block the transmission can lead, is not provided (DE-08 29 01 051), 3s is still named at such a control device with only one pressure valve during a shift down-control a switching element to be released or a switching element to be applied to drive up. Here is controlled by two solenoid valves Shift valves have a hydraulic lock between the three forward gears forming switching elements achieved.

Due to the total locking and the fact that only one pressure regulator is used, however, no overlapping control of switching elements is possible be made, i.e. the control is on the two freewheels in the gearbox instructed (DE-OS 29 47 897).

Advantages of the Invention The control device according to the invention with the Characteristic features of the main claim has the advantage of having two pressure regulating valves the various circuits with overlap control to run and using the example of a four-speed transmission that is common today, the three Saving freewheels in the transmission without sacrificing the greatest possible safety.

An absolute lock in the hydraulic control against simultaneous Engaging several gears can not be in favor of the overlap control can be realized, but the present four-speed only allows incorrect overlaps to. A constant engagement of several gears or a gear change in which the one to be released Switching element remains under full contact pressure is not possible.

It is particularly advantageous that the freewheels are no longer available the usually split clutches u combined into a common clutch can be.

The intervention in the gear mechanism offers the possibility of the freed Use installation space for the design for higher performance. The control is like this executed, that with the help of the planetary gear set for the fourth Gear (overdrive - translation) can form a second reverse gear after through the omitted freewheel a reverse direction of rotation is possible. This is general also possible while maintaining the freewheel if the planetary gear set is for the fourth Gear is arranged in front of the other two planetary gear sets.

Drawing An embodiment of the invention is i the drawing and explained in more detail in the following description. It show figure 1 shows a schematic drawing of a four-speed automatic transmission, FIG. 2 shows a shift pattern, FIG. 3 shows part of the control device, FIG. 4 shows a hydraulic switching device in a schematic representation.

Description of the exemplary embodiment Tn Figure 1 is 10 with a Converter clutch designated with 11, 12, 13 the three planetary sets of a four-speed automatic transmission and with A, B, C, D, E and F the shifting elements or clutches of the powershift transmission; this does not require any freewheels. The couplings are made according to the respective Drive level and the required gear one after the other in different combinations actuated, i.e. switched on or released, the hydraulic control device has a pressure medium source 15 in the form of a collecting container to actuate the couplings on - see Figure 3 - from which br a suction line 16 by means of a pressure medium pump 1 pressure medium promoted in a main pressure line 18 wirc The pressure in the main pressure line 18 is controlled by a main pressure valve 19 depending on the load. A converter feed line 29 leads from the main pressure valve via a pressure control valve 21 to a hydrodynamic torque converter 22, from which the pressure medium is fed to the lubrication system of the gearbox. Structure and mode of operation of the above described part of the hydraulic control device are known and z. 3. in DE-AS 26 58 195 set out in detail, so that this is not the case at this point needs to be discussed in more detail.

There is a manually operated hydraulic line on the main pressure line Selector slide 23 connected for preselecting different speed levels. The selector slide has a known way a P-, an R-, an N-, a D-, a 3-, a 2- and a 1 position on. P stands for parking, R for reverse gear, N for neutral position, D for the drive gear, in which the powershift transmission automaviscn into the different gear number steps is switched, 3 stands for a speed step with blocked fourth gear, 2 stands for a gear with blocked third and fourth gear and 1 for a drive position with blocked second, third and fourth gear.

Three services 25, 26 and 36 go from the selector slide 23 - see now figure # - - which lead into the actual hydraulic control device. from the line 26 branches off a line 27 in which a changeover check valve 28 is arranged, a second connection 27 'on the changeover check valve 23 is on line 36 connected, which leads to clutch A at the same time. From the non-return valve 23 leads out a line 29 which opens into a line 30 in which two pressure regulating valves 31, 32 arranged are. A line leads from the pressure control valve 31 33 to a switching valve 34, from which it continues to a reversing valve 35 for reverse gear.

on the line 25 branches off a line 38, which has a changeover check valve 39 leads to a safety valve 48. A line goes from the pressure control valve 32 41, which leads to a switching valve 140 and continues from there to the reversing valve 35.

From the line 26 also branches off a line 42, which has a Alternating check valve 43 leads to switching valve 40. The second feed line to the shuttle check valve 43 is on the one hand with a safety valve 5, on the other hand with the clutch B. tied together. 7on the pressure line 25 branches off a line 47, which leads to a second Safety valve 48 leads. From this a line 65 branches off to the safety valve 45 from. A line 50 leads from the safety valve 43 to clutch D, from the safety valve 45 another line 49 to coupling C.

Two control valves 52, 53 are connected in parallel to line 26, with a line 54 emanating from the control valve 52, which opens into a line 55, in which an alternating check valve 56 is arranged. The control valve 52 is from acted upon on one side via a line 57 which is connected to the line 55 is, from the other side via a line 58 which leads to reversing valve 35. The control valve 53 is controlled from one side via a line 59, which emanates from a line o0, in which a changeover check valve 61 is arranged is. The pressure ifl acts on the control valve 53 against the pressure in the line 59 a line 62, which is also to the reversing valve 35 leads. A line 63 extends from the control valve 53 and opens into the line 60. The second Connections of the changeover check valves 56 and 61 are connected to the reversing valve 35 connected, the outputs each lead to the switching valve 73.

In the control circuit there is also a reversing valve e5, to which one Line 66 leads up, which emanates from a solenoid valve 67. The reversing valve 65 is controlled from one side via a line 68 which is connected to the line 38 is connected, from the other side via a line 69 which is connected to a line 70 is connected, which extends from a second solenoid valve 71. The line 70 leads to one side of the switching valve 314, to the other Side a line 72 2 opens, which is connected to the line 26 The line 25 leads to a third switching valve 73, on one end of which there is a line 74 is connected, which comes from the Jmsteuerventil 65 here. From the switching valve 73 leads a line 76 to clutch 3, a line 77 to clutch B and a line 78 to a safety valve 79. A line opens out at one end face 80, which emanates from the line 25, opens a line at its other end face 81, which is connected to line 76.

The activation of the clutches with the two pressure control valves 31, 32 enables optimal overlap control, which can be adapted in any way is and does not require freewheels. Despite the omission of the freewheels, it is the same as usual usual, purely hydraulically controlled gears with z. B. only a missing freewheel no complex hydraulic control necessary. Furthermore allows the present control by the additional planetary gear set for the fourth gear an arbitrarily switchable second reverse gear, which does not have any control-related Requires additional effort. This is the case when the line 26 is under pressure. All forward gears can be shifted via line 36. The solenoid valves 67, 71 are used to control the switching valves 3V, 40, = 3.

In the event of failure of the ones required to control the solenoid valves electronic control is in emergency mode depending on the position of the selector slide 23 the third forward gear or the first reverse gear engaged.

The solenoid valves 7, 71 take over together with the control valve 65 the control of the three switching valves 34, 40, 73 and determine the one to be inserted Corridor. NS; the reverse gear lock (switching the selector lever at high forward speed) no separate solenoid valve is required, as this is the task for the first reverse gear from pressure control valve 32 and for the second reverse gear from pressure control valve 31 is perceived.

Control device or the control concept is built so that only an erroneous overlap is left. Constantly engaging several gears as well as a gear change in which both clutches to be controlled in the overlapping phase Receiving maximum pressure is not possible. This is done by the safety valves 5, 48, 79 (one achieved per gear change at which the pressure is to be controlled Coupling is compared with the constant main pressure. If the pressure is applied by a Pressure regulator in preparation for a switch below a predetermined threshold value lowered, the valve recognizes the functionality, so to speak of the pressure regulator and releases the feed channel to the other coupling. Persist the pressure regulator at maximum pressure (e.g. cable break), the second to be controlled Clutch cannot be activated because the safety valve in question does not switch. For gear changes between first and second gear and between second and the third gear is the higher, between the third and fourth gear against it the lower gear is preferred. This has the advantage that in emergency operation third gear (direct gear) or reverse gear is available.

Since the concept for the overlap control has two pressure regulators are available, an R 1 2 32 or R2 - R 1 gearshift can also be used in reverse be carried out in push or pull.

The interlocking of the switching and safety valves is designed in such a way that that after taking out the gear jer der. Selector lever and then reselect the position D while driving the direct and regulated insertion of the driving state corresponding Ganges is possible. The taking out of the Jangen remains unconvincing, because the relevant couplings are emptied manually using the wiper slide.

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Claims (3)

Claims (1.) Hydraulic control device for powershift transmissions, in particular for automatic transmissions in motor vehicles, in which from a pressure medium source Pressure means for actuating switching elements, in particular clutches, in a Main pressure line is conveyed, with a connected to the main pressure line, manually operated hydraulic selector slide for preselecting an age level, with a pressure line that can be connected to the main pressure line via the selector slide and with switching valves connected to the switching elements and actuating them, characterized in that to the main pressure line (26, 36) via a shuttle valve (28) two pressure control valves (31, 32) with a proportional pressure curve for the circuit of the gears are connected, and that two solenoid valves (67, 71) are provided, which, together with a reversing valve (65), controls three switching valves (34, 40, 73) to determine the individual courses. 2. Device according to claim 1, characterized in that there are three safety valves (45, 43, 79) are provided, to which the pressure of a clutch to be controlled with is compared to the constant main pressure. 3. Device according to claim 1 and / or 2, for a transmission with four Planetary sets, characterized in that this results in an arbitrarily switchable second Reverse gear can be represented.