Locking valve for operating a gearbox control unit

Abstract

Snap-action valve (10) with: a sliding piston (82) which is movable in a chamber and which has a first and second web surface (84; 86); a first connection (90) which is opened and closed by the first web surface (84) which is designed to receive a line pressure; a second connection (96) which is opened and closed by the second web surface (86) and which is designed to receive a control pressure; a third connection (92) located between the first (90) and second (96) connections, which alternately connects the first (90) and second (96) connections through the chamber to a transmission control element (94); a fourth port (98) which is designed to receive the control pressure and which, when pressurized, is designed to close the second port (96) and to open the first port (90) against the resistance of a spring force, wherein the second (96) and fourth port (98) are connected to a control pressure source which is generated by a control valve; a second sliding piston (14) which is movable along the chamber; and a magnetic coil component (26) which has a pin (24) for moving the second sliding piston (14).

Description

[0001] This invention generally relates to a regulator sliding piston valve controlled by a direct-acting solenoid coil with a multiplex latching valve and arranged in a machine-made control body of an automatic transmission.

[0002] In particular, the invention relates to a latching valve according to claim 1.

[0003] An automatic transmission incorporates a hydraulic system for regulating fluid pressure and flow in the various lines connected to the transmission components. The system includes a regulating spool valve housed within a control body, which is machined in a transmission manufacturing plant. This body, preferably made of an aluminum alloy, is commonly referred to as a valve body. The system components are assembled within the valve body and have transmission functions that are factory-machined.

[0004] A solenoid-operated control valve regulates the pressure that is transferred from the valve to a clutch or brake, whose engagement and disengagement state determines the gear in which the transmission operates.

[0005] Transmission clutch regulators require a method to supply hydraulic pressure to the clutches and brakes under high-torque operating conditions, such that the required pressure can be generated independently of the control pressure range suitable for displacement control. Separating the static performance (high torque) and dynamic control pressure ranges is achieved through the use of detent valves.

[0006] The typical latching valve works by overriding the clutch regulator's control by reducing the return pressure at the sliding piston. This causes the sliding piston to lose its force equilibrium, resulting in it moving to its limit and thus opening the unrestricted transmission between the supply and control pressure ports. The subsequent siphoning of pressure at the return port and the subsequent valve movement lead to a considerable delay and a drop in clutch control pressure when transitioning back to the dynamic pressure control state.

[0007] From DE 10 2005 032 103 A1 a hydraulic piston directional control valve for preferred use in a vehicle transmission with three ports and two piston sections is known, in which electromagnetic actuation can be carried out via a fourth port.

[0008] The invention is based on the objective of providing a latching valve which is formed in a valve body and which operates with a regulating valve in such a way that the displacement control of a transmission control element can be isolated from the high pressure which is used to provide the performance of the control element when transmitting a large torque when the element is engaged, which will remedy the deficiencies associated with a changing regulator feedback pressure, and which can be used in conjunction with separate devices, such as the direct acting solenoid coils.

[0009] The aforementioned problem is solved by means of a latching valve with the features of claim 1.

[0010] Advantageous embodiments of the invention are described in the dependent patent claims.

[0011] A latching valve has a first port to receive line pressure, a second port to receive control pressure, a third port located between the first and second ports which alternately connects the first and second ports to a transmission control element, and a fourth port to receive control pressure which is designed to close the second port and open the first port against the resistance of a spring force.

[0012] A method for operating the latching valve includes: supplying a line pressure to a first port, supplying a control pressure to a second port, alternately connecting the first and second ports to a transmission control element via a third port situated between the first and second ports, controlling the valve using the control pressure directed to close the second port and open the first port against the resistance of a spring force, and latching the valve when the first port opens and the second port closes.

[0013] A multiplex latching valve, which can continue its movement across the pressure range of the governor valve, has a dual function as a source of elasticity to stabilize the governor valve when the transmission control element is not connected to the governor valve. This combination keeps the governor valve in a pressure state with normal feedback, even when the control element is latched at line pressure.

[0014] The latching valve is actuated by the regulator control pressure to selectively apply either the regulator control pressure or the line pressure to the control element.

[0015] The multiplex architecture can be applied either to coupling systems consisting of a control valve with an adjustable solenoid outlet (VBS) or to direct-acting solenoid systems. For the direct-acting solenoid system, latching occurs without the addition of another solenoid, either by supplementing the force of the primary solenoid or as an on / off control of a similar multiplex latching valve.

[0016] The latching valve provides a circuit elasticity to stabilize the regulator valve after it is disconnected from the coupling, thus eliminating the need for a separate pressure accumulator part.

[0017] The scope of application of the preferred embodiment will become apparent from the following detailed description, the claims, and the drawings. It should be understood that the description and the specific examples serve only for illustration, although they characterize preferred embodiments of the invention. Persons skilled in the art will recognize various modifications and variations from the described embodiments and examples.

[0018] The invention will be easier to understand by referring to the following description, which is accompanied by the drawings, in which: Fig. 1 is a cross-section of a direct-acting solenoid control valve and a latching valve integrated in a base body; Fig. 2 a cross-section of a modified version of the valve of Fig. 1 is, where the sliding piston is removed from the valve chamber; Fig. 3 is a cross-section of a direct-acting solenoid control valve integrated in a base body, showing the sliding piston located in the valve chamber; Fig. 4 a graphical representation of the control element pressure and the solenoid coil current during the control element's engagement; and Fig. 5 graphical representations of the release pressure and the position of the control slide piston when the detent valve is released are shown.

[0019] The direct-acting solenoid-coil hydraulic valve 10, integrated into a base body, which is in Fig. 1 and Fig. Figure 2 shows a valve body 12 made of cast metal, preferably an aluminum alloy. The valve body 12 includes a valve slide piston 14 provided with web surfaces 16-19; a compression spring 20 that pushes the slide piston to the right; an adapter 22; an armature pin 24 that extends through the adapter and contacts the slide piston; an electromagnetic coil 26 that drives the pin to move to the left when the solenoid coil is energized and allows movement of the slide piston to the right when the solenoid coil is de-energized; and a second compression spring 28 to keep the pin in contact with the slide piston.

[0020] Preferably, the spring 20 has a relatively small spring constant, so that the control pressure generated by the valve 10 is essentially zero when no electric current is supplied to excite the solenoid coil 26.

[0021] The valve body 12 is equipped with: control ports 30, 42, through which the control pressure is transmitted to the chamber 32, which contains the sliding piston 14; a line pressure port 34, through which the line pressure is transmitted to the chamber; a sump port 36, through which the hydraulic fluid flows from the chamber into a low-pressure sump; and suction ports 38, 40, through which the chamber 32 is connected to a low-pressure suction system.

[0022] The elastic force generated by a spring clip 44, which is attached to the outer surface of a housing 45 surrounding the magnetic coil 26, keeps an adapter 22 in constant contact with an installation reference plane or reference surface 46 formed in the sump connection 36.

[0023] In operation, the valve 10 regulates the control pressure at port 30 and the return pressure at port 42 by generating a first sum of the force of spring 20 and the total force directed to the right due to the control pressure at port 42, which acts on the differential areas of the web surfaces 16 and 17. The balancing of this first sum of forces is a second sum of forces directed to the left, comprising the force of the pin 24 driven by a solenoid coil and the force of spring 28. As the force of pin 24 increases, the valve 10 opens a connection via the control edge 49 between the line pressure at port 34 and the control pressure at ports 30 and 42. When the control edge 49 opens, the control pressure increases.When the control pressure increases sufficiently for the current position of the pin 24, the differential feedback control pressure at the web surfaces 16, 17 causes the control edge 49 to close a connection between the control pressure port 30 and the low-pressure extraction through the chamber 32, the extraction port 38 and the passage 72, and causes the control edge 48 to open this connection.

[0024] Both the control edges 48, 49 and the installation reference plane or reference surface 46 in the valve body are simultaneously machined by a single impact-tooth milling tool. The solenoid coil assembly 50 comprises the adapter 22, the solenoid coil 26, the housing 45, and the spring 28.

[0025] All edges requiring precise relative positioning are milled in a single operation due to improved tolerances and manufacturing efficiency. Because of the improved edge quality, positional accuracy, and the elimination of post-processing, the control edges are precision-milled instead of cast. The high-precision tolerances allow for accurate flow control and pressure regulation. These tight tolerances also enable flow control using a short-stroke magnetic section 50.

[0026] Without changing the tolerances, a single measuring control pressure connection 30 (metered inlet - metered outlet, as in Fig. 1 shown) or on the control surface 52 a double measuring control pressure connection 30, 38 (metered flow - metered flow, as in Fig. (as shown in section 3). A clear classification of tolerance commitment has been established for the two production groups.

[0027] The in the Fig. The valves shown in 1-3 allow for standard central control designs (multi-hole including worm path), while the magnetic interface tolerances are provided.

[0028] A control pressure relief port 38 provides the sliding piston position control and stability. The absence of a dead zone improves the tracking response. It also prevents low-frequency oscillation across the dead zone.

[0029] The high precision of machine manufacturing allows for a minimum reduction in overlapping, which reduces the insensitivity range.

[0030] In Fig. 2. The diameter of the control rib surface 17 is larger than the diameter of the rib surface 16 of the valve 10'. The large diameter of the rib surface 16 of the valve 10' defines a sliding piston end damper 60 with a large diameter to increase stability, which allows the use of a contamination-resistant damper connection 62 with a relatively large diameter. The damper 60 is designed for minimal rebound delay and improved stability outside the rebound path 64. The diameter of the damper 60 is large in relation to the difference in diameters of the rib surfaces 16 and 17.

[0031] Combined with flow notches, the large diameter of the sliding piston web surface 16 and the damper 60 enables a high flow rate with the short-stroke magnet as well as a impact tooth milling manufacturing process.

[0032] The axial surface 68 of the adapter 22 is positioned in the chamber 32 due to its contact with the reference surface 46. This ensures that when the solenoid coil 26 is de-energized and the sliding piston 14 moves to the right within the chamber, the web surface 19 contacts the surface 68 before the armature pin 24 contacts a stop surface 70 in the solenoid coil component. This prevents the spring 28 from being fully compressed due to contact between its coils. In this way, the sliding piston end feature provides a clear stop to protect the solenoid coil component 50 against forced excessive travel.

[0033] The damping chamber 60 is equipped with an oil reservoir, using a higher-level vent opening 66, which is fed from the control pressure drain port 42.

[0034] The direct-acting solenoid hydraulic valves 10, 10" integrated in the base body each contain a detent valve 80 formed in the cast metal valve body 12. The valve 80 has: a sliding piston 82 formed with web surfaces 84, 86; a compression spring 87 that pushes the sliding piston 82 to the right; the suction port 88; the line port 90, which is connected to a source of line pressure of substantially constant magnitude; an outlet port 92, through which a clutch or brake 94 of the transmission is actuated; a control port 96, which is connected via the passage 64 to the control pressure ports 30, 42 of the governor valve 10; and a control pressure return port 98, which is also connected via the passage 64 to the control pressure ports 30, 42 of the governor valve 10. The connection is established.

[0035] In the operating state, the valve 80 supplies the actuation pressure via line 100 to the cylinder 102 of a hydraulic servo unit, which actuates the transmission control element 94. If the force generated by the control pressure is less than the load applied by the spring, the spring 87 pushes the sliding piston 82 towards the right end of the chamber, thereby closing the line port 90, opening the control port 96, and transferring the fluid at the control pressure via the outlet port 92 and line 100 to the control element 94. If the control pressure increases, the sliding piston 82 moves axially to the left along the valve chamber as a result of a force generated by the control pressure in the return port 98, which opposes the force of the spring 87.Once the coupling is fully engaged and the control pressure continues to increase, the web surface 86 gradually closes the port 96, and the web surface 84 keeps the line port 90 closed. With a further increase in control pressure, the web surface 86 closes the control port 96, and the web surface 84 opens a connection between the line port 90 and the outlet port 92, bypassing the valve 80 and pressurizing the control element 94 using the line pressure, which relies on the static capacity of the couplings. If the control pressure continues to rise after the valve 80 engages, the line pressure alone is used to bring the control element 94 into full engagement. The sliding piston 14 of the control valve 10 remains in its regulating position as long as the valve 80 is engaged.

[0036] The valve 80 is disengaged by reducing the control pressure, which causes the web surface 84 to close the line connection 90 and the web surface 86 to reopen a connection between the control connection 96 and the transmission control element 94 via the outlet connection 92 and the line 100.

[0037] Fig. Figure 4 shows the change in outlet pressure at port 92 in response to the current in the solenoid coil 26. The first part of the dependency occurs when the control pressure increases, while the control port 96 is connected to the outlet port 92 and the line port is closed. The second part, 106, occurs after point 108, where the control port 96 closes and the constant line pressure opens the outlet port 92 via port 90, bringing the control element to full power at 110. The two parts enable increased pressure-current resolution (reduced gain) while maintaining the overall achievable pressure range, as can be seen by comparing the system change without a latching feature.

[0038] The return chamber 102 of valve 80 is not emptied when valve 80 is locked, thus preventing air from entering the line feed control element 94. Since the return chamber 102 of valve 80 is not emptied when valve 80 is locked, these lines do not need to be refilled when valve 80 is unlocked.

[0039] Together, the control valve 10 and the latching valve 80 provide functional advantages in the transition states of the clutch control by performing the latching transition while maintaining the control operation. How Fig.Figure 5 shows that when the valve 80 disengages, the position 112 of the sliding piston 14 of the regulator valve 10 remains in a control measuring position, since its sliding piston has adjusted itself to the idle flow 96 and the compliance volume 98 during engagement, and provides a better transition to controlling the line 100 and the control element 94 when switching compared to a VBS regulator latching valve system 114.

[0040] In a VBS regulator latching valve system, pressure drops 116 usually occur below the desired release pressure 118, whereas the release pressure transition 120, which is generated by the combination of valves 10, 80, follows the desired release pressure 118 exactly, with practically no drop.

[0041] The latching valve can be used in both VBS / VFS actuated sliding piston valves and direct acting solenoid-controlled systems. Reference symbol list 10.10' Solenoid coil hydraulic valve 12 valve bodies 14 valve sliding pistons 16-19 walkway surfaces 20 compression springs 22 adapters 24 Anchor pin 26 Magnetic coil 28 second compression spring 30 control connection 32nd Chamber 34 Line pressure connection 36 sump connection 38 Extraction port 40 Extraction port 42 Control connection transfer 44 spring clips 45 cases 46 Installation reference level, reference area 48 Control edge 49 Control edge 50 magnetic coil components 52 Control surface 60 sliding piston end dampers 62 Contamination-resistant damper connection 64 passage 68 axial surface of the adapter 70 Stop area 72 Passage 80 Snap-in valve 82 sliding pistons 84, 86 web surfaces 87 Compression spring 88 Extraction port 90 Line connection, first connection 92 Outlet connection, third connection 94 Clutch or brake 96 Control connection, second connection 98 Control pressure return connection, fourth connection 100 lines 102 cylinders, recirculation chamber 104 first part in the diagram 106 second part in the diagram 108 points in the diagram 110 points in the diagram 112 Position of the sliding piston 114 VBS regulator snap-in valve system 116 pressure drops 118 Release pressure 120 Release pressure transition

Claims

[1] Snap-action valve (10) with: a sliding piston (82) which is movable in a chamber and which has a first and second web surface (84; 86); a first connection (90) which is opened and closed by the first web surface (84) which is designed to receive a line pressure; a second connection (96) which is opened and closed by the second web surface (86) and which is designed to receive a control pressure; a third connection (92) located between the first (90) and second (96) connections, which alternately connects the first (90) and second (96) connections through the chamber to a transmission control element (94); a fourth port (98) which is designed to receive the control pressure and which, when pressurized, is designed to close the second port (96) and to open the first port (90) against the resistance of a spring force, wherein the second (96) and fourth port (98) are connected to a control pressure source which is generated by a control valve; a second sliding piston (14) which is movable along the chamber; and a magnetic coil component (26) which has a pin (24) for moving the second sliding piston (14). [2] Snap-in valve (10) according to claim 1, wherein the chamber is able to alternately connect to the first (90) and second port (96), and the chamber is constantly connected to the third port (92). [3] Snap-action valve (10) according to claim 1, wherein: the chamber is constantly connected to the third connection (92); the first web surface (84) opens a connection between the first connection (90) and the third connection (92) through the chamber when the second web surface (86) closes the second connection (96); and the second web surface (86) opens a connection between the second connection (96) and the third connection (92) through the chamber when the first web surface (84) closes the first connection (90). [4] Snap-action valve (10) according to claim 1, wherein: the Chamber is able to connect alternately with the first (90) and second (96) connection; the chamber is constantly in contact with the transmission control element (94) and the fourth connection (98); the sliding piston (82) is displaceable in the chamber by a force generated by a spring (87) and a force generated by the control pressure in the fourth port (98). [5] Snap-action valve (10) according to claim 1, wherein the first web surface (84) has a first surface located at an inner axial end of the first web surface, the first surface having a first region; and the second web surface (86) has a second surface located at an inner axial end of the second web surface, the second surface having a second area which is substantially the same as the first area. [6] Snap-in valve (10) according to claim 5, wherein the second web surface (86) has a third surface located at an outer axial end of the second web surface, wherein the third surface has a region which is substantially the same as the second region. [7] Snap-action valve (10) according to claim 1, further comprising: a metal cast valve body (12) having a chamber and a control pressure port; Control edges that are machine-made in the valve body (12) at the control pressure port; and a reference surface (46) which is machine-made in the valve body (12), wherein the pin (24) of the solenoid coil component (26) is in contact with the reference surface (46) in the chamber.

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