Hydraulic control device of a dual-clutch transmission

Abstract

Hydraulic control device (1) of a dual-clutch transmission, comprising at least one pressure control valve (3), several gear selector valves (4), and two clutch selector valves (6, 7), wherein the gear selector valves (4) can be supplied via the at least one pressure control valve (3), wherein in the event of a failure of the at least one pressure control valve (3), the gear selector valves (4) and at least one of the clutch selector valves (6, 7) can be supplied, characterized in that two safety valves (S1, S2) associated with the clutch selector valves (6, 7) are provided, wherein at least one of the safety valves (S1) is functionally connected to the gear selector valves (4) via a bypass line (8), wherein in a bypass valve position of the safety valve (S1) the pressure control valve (3) can be bypassed by means of the bypass line (8), wherein the two safety valves (S1,S2) and the pressure regulating valve (3) are connected to a system pressure line (2), wherein the two safety valves (S1, S2) are connected to an oil sump (9) and to one of the two clutch actuator valves (6, 7).

Description

[0001] The invention relates to a hydraulic control device for a dual-clutch transmission according to the preamble of claim 1.

[0002] From DE 102 43 282 A1, a hydraulic control device for a dual-clutch transmission is known. The hydraulic control device has a pressure supply unit and two identical control branches, which are connected to each other via a system pressure line and an oil sump line. The pressure supply unit provides system pressure in the system pressure line. The control branches are each assigned to one of two sub-transmissions of a dual-clutch transmission with two friction clutches. Two pressure control valves are provided, with one pressure control valve assigned to each of the control branches. Each of the control branches has two gear selector valves and one clutch selector valve. The corresponding pressure control valve is located upstream of the two gear selector valves and the clutch selector valve.The two pressure regulating valves are designed as 3 / 3-way proportional valves with three ports. The first port is connected to the system pressure line, the second to the oil sump line, and the third to the two gear selector valves and the clutch selector valve via a branched supply line. A single-acting actuator is used as the clutch selector. Double-acting differential actuators are used as the gear selectors.

[0003] From EP 1 635 091 A1, a hydraulic control device for a dual-clutch transmission is known. The control device comprises a first pressure control valve and a second pressure control valve. On the input side, the two pressure control valves are connected to a system pressure line, which carries a system pressure. A first changeover valve is located downstream of the first pressure control valve, and a second changeover valve is located downstream of the second pressure control valve. The first changeover valve allows the first pressure control valve to be connected either to a first clutch actuator valve or to a pressure switch. The pressure switch is connected via a line to a shift system. The shift system includes the corresponding gear actuator valves. By means of the second changeover valve, a regulated pressure from the second pressure control valve can be switched either to the pressure switch or to a second clutch actuator valve.The control device is characterized by the fact that the first switching valve, in a first position A1, connects the first pressure regulating valve to the first friction clutch and disconnects it from the shifting system, and in a position B1, connects the first pressure regulating valve to the shifting system and disconnects it from the first friction clutch; and that the second switching valve, in a position A2, connects the second pressure regulating valve to the second friction clutch and disconnects it from the shifting system, and in a position B2, connects the second pressure regulating valve to the shifting system and disconnects it from the second clutch. This design of the switching valves and the arrangement of the pressure regulating valves allows the shifting system to be connected to both pressure regulating valves for gear selection via the corresponding positions B1 and B2.In position B1 of the first changeover valve and in position B2 of the second changeover valve, the first pressure control valve is connected to the second friction clutch, and the second pressure control valve is connected to the first friction clutch. This allows at least one of the two friction clutches to be actuated even if one of the pressure control valves has failed. This enables either the first or the second pressure control valve to provide a regulated pressure or flow rate for the shifting system, i.e., for gear selection. This control device thus allows gears to be shifted regardless of which of the two pressure control valves fails. If one of the two pressure control valves fails, shifting without interruption of traction is no longer possible. However, the dual-clutch transmission can still be shifted into any gear and operated in that gear.For example, if the first pressure regulating valve fails, the first coupling can be actuated via the second pressure regulating valve as soon as both the first and second changeover valves are in positions B1 and B2, respectively. The second coupling can also be actuated by the second pressure regulating valve when it is switched to position A2.

[0004] From EP 1 767 825 A1, a hydraulic control device for an automated dual-clutch transmission is known, comprising two pressure control valves, namely a first pressure control valve and a second pressure control valve, as well as a gearshift system and two clutch actuator valves, namely a first clutch actuator valve and a second clutch actuator valve. The gearshift system is supplied via the two pressure control valves. The two clutch actuator valves serve to control two friction clutches of the dual-clutch transmission.

[0005] From EP 1 950 463 A1, a hydraulic control device for controlling a dual-clutch transmission is known, comprising two pressure control valves, two downstream changeover valves, and a changeover switch. In position A1, the first changeover valve connects the first pressure control valve to a first friction clutch, thereby disconnecting the first pressure control valve from a shift system with multiple gear selector valves. In position B1, the first changeover valve connects the first pressure control valve to the shift system, thereby disconnecting the first pressure control valve from the first friction clutch. In position A2, the second changeover valve connects the second pressure control valve to a second friction clutch, thereby disconnecting the second pressure control valve from the shift system. In position B2, the second changeover valve connects the second control valve to the shift system, thereby disconnecting the second pressure control valve from the second friction clutch.A changeover switch is provided between the first or second changeover valve and the shifting system. This switch ensures that the shifting system is supplied with either the pressure / volume flow of the first pressure control valve or the pressure / volume flow of the second pressure control valve. In position B1 of the first changeover valve and position B2 of the second changeover valve, a connection is established between the second pressure control valve and the first friction clutch, and the second friction clutch is essentially depressurized. The sub-transmission associated with the first friction clutch has several forward gears and one reverse gear. If one of the pressure control valves fails while in an open position, the changeover valves are positioned in positions B1 and B2. This is intended to provide an emergency driving function in the event of a pressure control valve failure.This control device prioritizes the first friction clutch, accepting the consequence that the second friction clutch will prevent the vehicle from being driven in emergency mode. This control device is not yet optimally designed. It requires a number of valves and an additional switch to provide an emergency driving function in the event of a failure of at least one pressure regulating valve.

[0006] The invention is therefore based on the objective of providing an emergency driving function in a cost-effective and simple manner in the event of the failure of at least one pressure regulating valve.

[0007] The problem underlying the invention is now solved by a hydraulic control device with the features of claim 1. Two safety valves are provided, each associated with a clutch actuator valve. At least one of the safety valves is functionally connected to the gear actuator valves via a bypass line. In a bypass position of the safety valve, the pressure regulating valve can be bypassed by means of the bypass line. In the bypass position, the associated downstream clutch actuator valve is no longer supplied with pressure, but the gear actuator valves are supplied with system pressure via the bypass line. The other clutch actuator valve is still supplied with pressure via the corresponding other safety valve. This allows, in particular, the second friction clutch to be opened and closed.This allows driving in all gears assigned to this friction clutch, particularly the gears assigned to the second friction clutch. The second friction clutch is preferably assigned a second forward gear and a reverse gear. The effort required to provide this safety function is minimal. In the event of a malfunction of the central pressure regulating valve, the safety valve assigned to the first friction clutch can be positioned in the bypass valve position, so that the bypass line and the downstream gear selector valves are supplied with pressure. The other, second friction clutch is supplied with a pressure / volume flow via the corresponding second safety valve and the second clutch selector valve, and can thus be opened and closed.While this eliminates the possibility of load-shifting operations, it allows the vehicle to be driven and maneuvered by engaging and disengaging the gears assigned to the second friction clutch. Preferably, only a single, common pressure regulating valve is provided, which is located upstream of the gear actuator valves. This central pressure regulating valve supplies all gear actuator valves, thus reducing the number of valves required. If the central pressure regulating valve should malfunction and fail, the gear actuator valves are supplied via one of the safety valves through the bypass line. The bypass line connects a port of this first safety valve to a correspondingly branched supply line for the gear actuator valves. The two safety valves and the pressure regulating valve are connected to a system pressure line.The two safety valves are also connected to an oil sump and to one of the two clutch actuator valves. The supply line to the gear actuator valves can be connected to the oil sump via the bypass line and the associated safety valve. In the bypass position of the safety valve, a connection is provided between the system pressure line and the bypass line, and the connection between the system pressure line and the associated clutch actuator valve is blocked. The friction clutches are open in their normal position. When the clutch actuator valves are depressurized by the safety valves, the friction clutches are open. Both safety valves also provide a safety shutdown function for the downstream friction clutches.The safety valve providing the bypass valve position is preferably assigned to the first friction clutch, which is assigned at least one forward gear and one reverse gear. Dual-clutch transmissions are also known in the prior art in which one friction clutch is open in its home position ("normally open") and the other friction clutch is closed in its home position ("normally closed"). The control device can also be used in this dual-clutch transmission, with the safety valve providing the bypass valve position advantageously assigned to the "normally open" friction clutch. This ensures that, in the event of a failure of the pressure control valve, the sub-drive train or sub-transmission to which the safety valve providing the bypass valve position is assigned is most easily opened.It is also conceivable that the safety valve with the bypass valve position is also assigned to the "normally closed" friction clutch. However, in this case, it must be switched to neutral in this sub-transmission if the pressure regulating valve fails, in order to disconnect the sub-drivetrain. Under such conditions, the control device can then also be used in a dual-clutch transmission with both "normally closed" friction clutches. The disadvantages mentioned at the beginning are therefore avoided, and corresponding advantages are achieved.

[0008] There are now numerous possibilities for advantageously designing and further developing the aforementioned control device. For this purpose, reference may first be made to the claims subordinate to claim 1. In the following, a preferred embodiment of the invention will be explained in more detail with reference to the drawing and the accompanying description.

[0009] The drawing shows: Fig. 1 in a schematic representation a part of a hydraulic control device according to the invention with a central pressure regulating valve, with two coupling actuator valves and with two safety valves upstream of the coupling actuator valves as well as with a bypass line, Fig. 2 in a schematic representation a detail of the hydraulic control device Fig. 1, namely the pressure regulating valve and the safety valve in a first valve position, and Fig. 3 in a schematic representation the detail of the hydraulic control device according to Fig. 2, wherein the first safety valve is switched in a bypass valve position.

[0010] In Fig. Figure 1 shows a hydraulic control device 1 for a dual-clutch transmission (not shown), at least partially illustrated. The hydraulic control device 1 includes, in particular, a supply system (not shown). The supply system includes a fluid pump, corresponding filter devices, and the like. The supply system provides a system pressure PH at a system pressure line 2.

[0011] The hydraulic control device 1 preferably comprises exactly one pressure regulating valve 3 and several downstream gear actuator valves 4. The gear actuator valves 4 are supplied with a pressure / volume flow via the common pressure regulating valve 3. The pressure regulating valve 3 is located upstream of all gear actuator valves 4. The gear actuator valves 4 are supplied with a regulated pressure / volume flow via the pressure regulating valve 3. Only one gear actuator valve 4 is shown, but several gear actuator valves 4 are provided. The gear actuator valves 4 actuate corresponding, in particular double-acting, actuator cylinders 5 with two pressure chambers A, B. The other gear actuator valves (not shown) are supplied with pressure via a branched supply line 19.

[0012] The hydraulic control device 1 further comprises two clutch actuator valves 6, 7, wherein the clutch actuator valves 6, 7 are each assigned to one of the two friction clutches K1, K2. (The friction clutches K1 and K2 are not shown, however, the reference numerals K1 and K2 in Fig. 1, Fig. 2 to Fig. 3 (the assignment of the components to the friction clutches K1 and K2 is indicated.) The clutch actuator valve 6 is assigned to a first friction clutch K1 and the second clutch actuator valve 7 is assigned to a second friction clutch K2.

[0013] In the event of a failure of the pressure regulating valve 3, the gear actuator valves 4 and one of the clutch actuator valves 6, 7 can be supplied with a pressure / volume flow.

[0014] Each of the clutch actuator valves 6, 7 is preceded by a safety valve S1, S2, wherein at least one of the safety valves S1 is functionally connected to the gear actuator valves 4 via a bypass line 8, wherein in a bypass valve position of the safety valve S1 the pressure control valve 3 can be bypassed by means of the bypass line 8.

[0015] This has the advantage that gears can still be engaged and disengaged even if the central pressure control valve 3 fails. The safety valve S1 ensures the supply to the gear selector valves 4 in the event of a fault. The safety valves S1 and S2 provide a safety shutdown function for the downstream friction clutches K1 and K2, which are open in their normal position. For example, in the Fig. In position 1 shown, the safety valve S2 connects the system pressure line 2 to the second clutch actuator valve 7.

[0016] The two safety valves S1 and S2 and the pressure regulating valve 3 are connected to the system pressure line 2. The two safety valves S1 and S2 are also connected to an oil sump 9 and to one of the two clutch actuator valves 6 and 7.

[0017] The first safety valve S1 offers the bypass valve position, which the second safety valve S2 preferably does not have. However, it is conceivable that both safety valves S1 and S2 offer a corresponding bypass valve position and that a correspondingly branched bypass line is provided (not shown). In the bypass valve position, the bypass line 8 is connected to the system pressure line 2 via the safety valve S1 (see figure). Fig. 3) The first clutch actuator valve 6 is specifically depressurized, so that the first friction clutch K1 is open. The second friction clutch K2, however, can be opened and closed, so that the corresponding gears, in particular a second, fourth, and sixth forward gear as well as a reverse gear, can be shifted by means of the associated gear actuator valves 4. This provides a simple emergency driving mode. This design can be implemented with minimal construction effort. Although the gears can no longer be shifted under load, the dual-clutch transmission can be operated with the functioning friction clutch K2 in the manner of an automated manual transmission.

[0018] The bypass line 8 branches from the safety valve S1 into a first bypass line branch 10 and a second bypass line branch 11. The bypass line branch 10 connects the bypass line 8 to an unspecified port of the pressure regulating valve 3. A check valve 12 is arranged in the bypass line branch 11. The bypass line branch 11 is functionally connected to a working port of the pressure regulating valve 3.

[0019] The pressure regulating valve 3 has three ports. The first port is connected to the system pressure line 2. The second port is connected to the bypass line branch 10. The third port, or working port, is functionally connected to the supply line to the variable speed control valves 4 and the bypass line branch 11. In the normal position of the pressure regulating valve 3, the first port is closed, and the second and third ports are connected to each other. This connects the supply line 19 to the variable speed control valves 4 to the bypass line branch 10. In a neutral position, all three ports are closed. In a working position of the pressure regulating valve 3, the system pressure line 2 is connected to the supply line 19, and the bypass line branch 10 is closed. The check valve 12 in the bypass line branch 11 closes the bypass line branch 11 due to the system pressure PH applied to the check valve 12.

[0020] The safety valve S1 has four ports, with a first port being connected to the system pressure line 2 and a second port being connected to the oil sump 9. A third port is connected to the bypass line 8 and a fourth port is functionally connected to a corresponding supply line (not further specified) of the first clutch actuator valve 6.

[0021] In the Fig. In the basic position of the spring-loaded first safety valve S1 shown in Figure 1, the first connection, i.e., the system pressure line 2, is closed, and the third and fourth connections – with the bypass line 8 and with the supply line to the coupling actuator valve 6 – are connected to the second connection, i.e., the oil sump 9. In a middle position of the safety valve S1 (see Figure 1), the first connection is closed. Fig. 2) The bypass line 8 is connected to the oil sump 9 and the system pressure line 2 to the clutch actuator valve 6. In the bypass valve position (see Fig. 3) of the first safety valve S1, the second and fourth ports are blocked and the system pressure line 2 is connected to that of the bypass line 8.

[0022] The second safety valve S2 is designed as a 3 / 2-way valve and has three ports, the first port being connected to the system pressure line 2 and the second port to the oil sump 9. The third port of the safety valve S2 is connected to the clutch actuator valve 7 via a corresponding supply line. In the Fig.In the basic position of the second safety valve shown in Figure 1, the second clutch actuator valve 7 is depressurized and connected to the oil sump 9. In the other position of the second safety valve S2, the second clutch actuator valve 7 is connected to the system pressure line 2.

[0023] The clutch actuator valves 6, 7 have three ports. The first port is connected to the safety valves S1 and S2, respectively, as described above, and the second port is connected to the oil sump 9. The third port is connected to the corresponding actuator cylinders 14, 15. The clutch actuator valves 6, 7 are electrically actuated and spring-loaded. A single-acting actuator cylinder 14, 15 is provided for actuating the respective friction clutch K1, K2.

[0024] A measuring orifice 16 is arranged on the outlet side of each pressure regulating valve 3 and each of the coupling actuator valves 6, 7. A check valve 12 is arranged parallel to each coupling valve 6 and its associated measuring orifice 16. A pressure gauge 17 is arranged downstream of each coupling actuator valve 6, 7. The pressure gauge 17 measures the pressure between the measuring orifice 16 and the respective actuator cylinder 14, 15.

[0025] Filter elements 13 are arranged between the system pressure line 2 and the pressure regulating valve 3 as well as the safety valves S1, S2. Further filter elements 13 are preferably assigned to the connections of the gear selector valves 4 and the clutch selector valves 6, 7.

[0026] A spring accumulator 18 is also arranged downstream of the pressure regulating valve 3. The spring accumulator 18 serves to compensate for pressure fluctuations in the supply line 19 of the gear selector valves 4. Reference symbol list 1 hydraulic control device 2 System pressure line 3 Pressure regulating valve 4 gear selector valve 5 actuator cylinders 6 Clutch control valve 7 Clutch control valve 8 Bridging line 9 Oil sump 10 Bridging line branch 11 Bridging line branch 12 Check valve 13 Filter element 14 actuator cylinders 15 actuator cylinders 16 measuring aperture 17 pressure gauges 18 spring accumulators 19 Supply line PH system pressure A pressure chamber B Pressure chamber S1 safety valve S2 safety valve K1 friction clutch K2 friction clutch

Claims

[1] Hydraulic control device (1) of a dual-clutch transmission, comprising at least one pressure control valve (3), several gear actuator valves (4), and two clutch actuator valves (6, 7), wherein the gear actuator valves (4) can be supplied via the at least one pressure control valve (3), wherein in the event of a failure of the at least one pressure control valve (3) the gear actuator valves (4) and at least one of the clutch actuator valves (6, 7) can be supplied, characterized by, that two safety valves (S1, S2) are provided for the clutch actuator valves (6, 7), wherein at least one of the safety valves (S1) is functionally connected to the gear actuator valves (4) via a bypass line (8), wherein in a bypass valve position of the safety valve (S1) the pressure control valve (3) can be bypassed by means of the bypass line (8), wherein the two safety valves (S1, S2) and the pressure control valve (3) are connected to a system pressure line (2), wherein the two safety valves (S1, S2) are connected to an oil sump (9) and to one of the two clutch actuator valves (6, 7). [2] Control device according to claim 1, characterized by , that exactly one common pressure control valve (3) is provided, wherein all gear actuator valves (4) can be supplied via the common pressure control valve (3). [3] Control device according to one of the preceding claims, characterized by, that in the bypass valve position the safety valve (S1) provides a connection between the system pressure line (2) and the bypass line (8) and a connection between the system pressure line (2) and the associated coupling actuator valve (6) is blocked. [4] Control device according to one of the preceding claims, characterized by, that the bypass line (8) is connected to an outlet of the associated safety valve (S1), wherein the bypass line (8) has two bypass line branches (10, 11), wherein the pressure control valve (3) is designed as a 3 / 3-way valve, wherein a first port of the pressure control valve (3) is connected to the system pressure line (2) and a second port of the pressure control valve (3) is connected to one of the bypass line branches (10), wherein the third port of the pressure control valve (3) is connected to the other bypass line branch (11) and to the gear selector valves (4), wherein this other bypass line branch (11) has a check valve (12). [5] Control device according to one of the preceding claims, characterized by, that the safety valve (S1) providing the bypass valve position is assigned to the first friction clutch, wherein the second friction clutch is assigned at least one forward gear, in particular a second forward gear, and one reverse gear. [6] Control device according to one of the preceding claims, characterized by , that the safety valve (S1) providing the bypass valve position is assigned to the first friction clutch, wherein the first friction clutch is designed as "normally open" and the second as "normally closed". [7] Dual-clutch transmission characterized by a control device according to one of the preceding claims.

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