Transmission element for a motor vehicle, in particular for a motor car

Abstract

Transmission element for a motor vehicle, comprising at least one hydraulic actuating element (12) which is hydraulically movable at least from a first position to a second position, and comprising an electric pump (14) by means of which a hydraulic fluid is conveyed to the actuating element (12) and thereby the actuating element (12) is hydraulically movable from the first position to the second position, wherein the electric pump (14) is operable in a first operating state in which the hydraulic fluid is conveyed by means of the pump (14) in a first direction and thereby towards the actuating element (12), whereby the actuating element (12), which is movable relative to a housing (18) of the actuating element (12) between the positions, is hydraulically movable from the first position to the second position;- the electric pump (14) is operable in a second operating state in which the hydraulic fluid is to be conveyed by means of the pump (14) in a second direction opposite to the first direction and thereby away from the actuating element (12) and from a reservoir (20) and towards at least one consumer (24) provided in addition to the actuating element (12), whereby the consumer (24) can be supplied with the hydraulic fluid; - the actuating element (12) has a first sealing surface (38);and the housing (18) of the actuating element (12) has a second sealing surface (40) corresponding to the first sealing surface (38), with which the first sealing surface (38) can be moved into a sealing position by the second operating state, whereby the actuating element (12) can be sealed directly against the housing (18), characterized in that the actuating element (12) has its first sealing surface (38) on an end face (34) of the actuating element (12), wherein the first sealing surface (38) is a guide-direction oriented sealing surface.

Description

The invention relates to a transmission element for a motor vehicle, in particular for a motor car, according to the preamble of claim 1. In DE 10 2012 010 172 A1, an actuator arrangement for a drive train with a clutch hydraulic cylinder is disclosed, which is directly connected to a pump connection of an electrically driven pump for actuating a friction clutch. German patent DE 10 2012 016 235 A1 discloses an actuator arrangement for a drive train as known. The actuator arrangement comprises an electrically driven actuator pump and a clutch actuator for actuating a friction clutch, which is connected to a pressure port of the actuator pump. In DE 10 2017 008 562 A1 a hydraulic valve, in particular for a hydraulic parking lock system, as well as a hydraulic parking lock system with the hydraulic valve is disclosed. German patent DE 10 2011 105 068 A1 discloses a transmission element designed as a parking lock for a motor vehicle, in particular for a car. The parking lock has at least one hydraulic actuating element, which can be moved hydraulically from a first position to a second position. Furthermore, a pump is provided by means of which hydraulic fluid is supplied to the actuating element, thereby enabling the actuating element to be moved hydraulically from the first position to the second position. The object of the present invention is to improve a transmission element of the type mentioned above, so that a particularly advantageous operation of the transmission element can be realized. This problem is solved by a transmission element with the features of claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims. To improve a transmission element of the type specified in the preamble of claim 1, the pump is designed according to the invention as an electric pump, i.e., as an electrically operated pump. Furthermore, the pump is reversible with respect to its delivery direction, in which the hydraulic fluid, for example oil, is delivered or is to be delivered by the pump. This means that the pump can be operated in a first operating state and in a second operating state. In the first operating state, the hydraulic fluid is delivered or is delivered by the pump in a first direction. In the second operating state, the hydraulic fluid is delivered or is delivered by the pump in a second direction, the second direction being opposite to the first. The respective direction is also referred to as the delivery direction or oil delivery direction.By operating the pump in the first operating state, and thus by pumping the hydraulic fluid in the first delivery direction, the hydraulic fluid is conveyed by the pump to the actuating element, thereby moving the actuating element, which is movable between positions relative to a housing of the actuating element, particularly translationally, hydraulically from the first position to the second position. Within the scope of the invention, it is conceivable that the housing of the actuating element and the actuating element are essentially integrated into an electro-hydraulic control unit and, in particular, are spatially spaced apart and / or not arranged directly in a transmission element housing. By operating the pump in the second operating state, and thus by means of the pump conveying the hydraulic fluid in the second conveying direction, the hydraulic fluid is conveyed away from the actuating element, and the hydraulic fluid is conveyed from a reservoir to at least one additional consumer provided besides the actuating element, thereby supplying the consumer with the hydraulic fluid. For example, the pump is fluidically or hydraulically connected via a connecting line to a receiving chamber, also referred to as an oil chamber, which is, for example, partially bounded by the actuating element and, in particular, partially bounded by the housing, preferably directly.When the pump is operated in the first operating state, it pumps hydraulic fluid through the connecting line, towards the actuating element, and into the oil chamber, thereby moving the actuating element from the first to the second position. When the pump is operated in the second operating state, it creates a vacuum in the connecting line and, via the connecting line, in the oil chamber. Alternatively, it pumps hydraulic fluid remaining in or absorbed from the oil chamber through the connecting line, specifically by suction. This causes, or at least allows, the actuating element to move from the second to the first position.Furthermore, in the second operating state, the oil is pumped from the reservoir, which may be designed as a tank or referred to as a tank, in such a way that the hydraulic fluid is pumped from the reservoir and especially from the oil chamber to the consumer. The consumer is, for example, a control system, particularly an electro-hydraulic one, or a component of such a control system, particularly for actuating and / or shifting a transmission. Furthermore, according to the invention, the actuating element has a first sealing surface, and the housing has a second sealing surface corresponding to the first sealing surface. In the second operating state, the first sealing surface is movable in, in particular, direct sealing contact with the second sealing surface, whereby the actuating element can be sealed directly against the housing. In other words, if the pump is operated in the second operating state such that a movement of the actuating element from the second position to the first position is effected or permitted, and it is particularly provided that the actuating element is drawn from the second position to the first position by the aforementioned negative pressure, the actuating element moves relative to the housing from the second position to the first position, thereby bringing the sealing surfaces into direct, mutual contact.This means the actuating element rests directly against the housing, thus sealing it directly against the housing without the need for an additional, separately designed sealing element. This prevents the pump from drawing in air in the second operating state, for example, from an area located downstream of the housing's sealing surface in relation to the first flow direction. For example, the actuating element has its first sealing surface on an end face of the actuating element, wherein the first sealing surface is preferably a guide-direction-oriented sealing surface. For example, the actuating element is guided in the housing. The second sealing surface is a contact surface of the housing. The aforementioned oil chamber adjoins, for example, the end face of the actuating element. The positions of the actuating element are also referred to as switching positions. By operating the pump, also known as an oil pump, in its first operating state, pressure can be generated in the receiving chamber (oil chamber). This pressure in the oil chamber can exert or generate a force acting on the front face, particularly on an end face located on the front face, which allows the hydraulic actuating element to be moved or moved into the second position. In one embodiment of the invention, the first delivery direction is achieved by moving, and in particular rotating, a delivery element for conveying the hydraulic fluid relative to a pump housing of the pump in a first direction of movement, in particular a direction of rotation, in the first operating state. The second delivery direction is achieved, in particular, by moving, and in particular rotating, the delivery element relative to the pump housing in a second delivery direction, and in particular a second direction of rotation, which is opposite to the first direction of movement, and in particular a second direction of rotation, in the second operating state. The second direction of movement, and in particular the second direction of rotation, is also referred to, for example, as the normal direction of movement, and in particular as the normal direction of rotation, since in the second operating state the consumer is supplied with the hydraulic fluid by means of the pump.With this embodiment of the invention, the first and second operating states can be represented in a particularly simple technical manner. In one embodiment of the invention, the gear element is designed as a parking lock. For a gear element designed as a parking lock according to the invention, it is particularly advantageous in the first operating state of the pump to essentially not supply the at least one consumer provided in addition to the actuating element, thus allowing the consumer to be supplied with hydraulic fluid, so that the functions of the at least one consumer remain essentially unaffected by the first operating state of the pump. In a further embodiment of the invention, by moving the actuating element into the second position, a locking element of the parking lock and / or a locking element of a parking lock piston can advantageously be moved into a first position in which the locking element unlocks the parking lock and / or the parking lock piston, in particular by positive locking. This releases the locking element that secures the parking lock and / or the parking lock piston against movement. The locking element is, for example, a detent element that engages in a piston rod connected to the parking lock piston or in the parking lock piston itself and thereby interacts positively with the piston rod or with the parking lock piston. In the second operating state, that is, by operating the pump in this state, the actuating element can be moved or brought into the first position. In the first position, the first sealing surface rests, in particular directly, against the corresponding second sealing surface of the housing. By moving the actuating element into this position, the locking element can be moved into a second position, in which it locks the parking lock piston. Thus, for example, in the second position, the parking lock piston is locked, rendering it immobile. The parking lock piston can be used to actuate a pawl of the parking lock. Specifically, moving the parking lock piston can cause movement of the pawl.When the parking lock piston is locked, it is secured against unwanted movement, thus preventing unintended actuation of the pawl by the parking lock piston. To actuate, i.e., move, the pawl using the parking lock piston, the parking lock piston is unlocked. The parking lock piston can then be moved to actuate the pawl. By actuating the pawl, the parking lock can be engaged and / or disengaged. In other words, by moving the parking lock piston, the parking lock, i.e., the pawl, can be engaged and / or disengaged. In particular, the sealing surfaces each have the contour of a dome, especially a spherical cap. In other words, it is conceivable that the sealing surfaces are each curved, especially spherical. In a further embodiment of the invention, it is possible for the sealing surfaces to be conically shaped. In other words, it is conceivable that each sealing surface has a conical contour. As previously mentioned, the pump can be operated in two directions of rotation. This means that the pumping element can be rotated in two opposite directions to achieve the different pumping directions. Furthermore, it is conceivable that the hydraulic actuating element is connected to a suction line of the pump, whereby the pump draws the hydraulic fluid from the reservoir through the suction line to provide the hydraulic fluid to the consumer. The following describes the engagement process of the parking lock: The driver of the vehicle, for example, operates a control device, thereby indicating "P". This means, for example, that the driver moves a control element into a parking lock position marked "P". Subsequently, the pump is switched off. This means, in particular, that the pump's operation in the second operating state, also known as the normal operating state, is terminated, and the pump no longer draws oil from the reservoir. The pump's direction of rotation then reverses. In other words, the pump's operating state changes, as the second operating state is first terminated and then the pump operates in the first operating state. This unlocks the parking lock piston, which was initially in its non-parking position.The parking lock piston is then moved from its non-parking position to its parking position, in particular by means of the aforementioned control system, thereby engaging the parking lock or pawl. Once the parking lock or pawl is engaged, the pump, in particular its first operating state, is stopped. A spring element associated with the actuating element moves, in particular pushes, the actuating element into its locking position, thereby locking the parking lock piston in its parking position. For example, operating the pump in the first operating state is only intended or necessary briefly to move the parking lock piston, or to allow movement or displacement of the parking lock piston. A quantity of hydraulic fluid, also referred to as oil quantity, that remains in the control system after the pump is switched off is sufficient to move the actuating element, also referred to as or designed as an actuating slide, in particular to displace it, especially into the second position.The invention is particularly intended for functions or situations that are required or occur at a time when all other functions, especially those of the control system, are not needed, because then the degree of freedom to operate the pump with reverse rotation, and particularly in the first operating state, can be used to implement a control function without conflicting with other functions. This is particularly relevant for functions of a transmission element designed as a parking lock according to the invention. According to the invention, the pump is decoupled from the drive motor for propelling the motor vehicle and can therefore be operated even after the drive motor has been switched off.Furthermore, the invention can be used very advantageously in systems with two electric pumps, in which a degree of freedom to operate one of the two pumps with a reversal of the direction of rotation in order to represent a control function could be given in principle or theoretically at least for selected situations. Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the single figure alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention. The drawing shows in the single figure a partial schematic representation of a transmission element designed as a parking lock for a motor vehicle, in particular for a car. The single figure shows a schematic representation of a partial view of a transmission element according to the invention, designed as a parking lock 10, for a motor vehicle, in particular for a motor vehicle preferably designed as a passenger car. The parking lock 10 has at least one hydraulic actuating element 12, which can be moved hydraulically, i.e., by means of a hydraulic fluid, for example, oil, from a first position to a second position. The parking lock 10 also includes a pump 14, by means of which the oil is pumped to the actuating element 12, thereby allowing the actuating element 12 to be moved hydraulically from the first position to the second position. As shown in the figure.As illustrated by a double arrow 16, the actuating element 12 can be moved translationally between the first position and the second position relative to a housing 18 of the actuating element 12, i.e., moved back and forth. The actuating element 12 is, for example, at least partially enclosed in the housing 18. Furthermore, a reservoir 20, also referred to as a tank, is provided in which the hydraulic fluid (oil) can be received or is contained. As illustrated by a double arrow 22 in the figure, the pump 14, designed as an electric pump, can be operated in a first operating state and a second operating state. The pump 14 is a reversible pump. When the pump 14 is operated in the first operating state, the hydraulic fluid is conveyed by the pump 14 in a first direction, also referred to as the first conveying direction, and thus towards the actuating element 12, thereby hydraulically moving the actuating element 12 relative to the housing 18 from the first position to the second position. When the pump 14 is operated in the second operating state, the hydraulic fluid is conveyed by the pump 14 in a second direction, opposite to the first, and thus from the reservoir 20 away from the actuating element 12 and towards at least one additional actuator provided in the figure.Consumer 24, shown in a particularly schematic way, is supplied with hydraulic fluid (oil). The figure shows that the actuating element 12 is fluidically and thus hydraulically connected to the pump 14 via a connecting line 26. A double arrow 28 in the figure illustrates that the hydraulic fluid can flow through the connecting line 26 in the first direction and in the opposite direction, also referred to as the second delivery direction, i.e., it can be pumped through the connecting line 26 by means of the pump 14. In the first operating state, the oil is pumped through the connecting line 26 in the first delivery direction by means of the pump 14, and in the second operating state, the oil is pumped through the connecting line 26 in the second delivery direction by means of the pump 14.It can be seen that the hydraulic fluid from the reservoir 20 can flow to the pump 14 via a filter 30 and a check valve 32, with the check valve 32 opening towards the pump 14 and closing in the opposite direction, and thus towards the reservoir 20. In the second operating state, the pump 14 creates a vacuum in the connecting line 26. In other words, in the second operating state, the pump 14 draws any oil that may have been absorbed in the connecting line 26 out of the connecting line 26. The housing 18 and the actuating element 12, in particular an end face 34 of the actuating element 12, each partially and directly define a receiving space, also referred to as an oil chamber 36.In the first operating state, for example, the pump 14 delivers the oil via the connecting line 26 into the oil chamber 36, thereby directly supplying the end face 34 with oil and moving the actuating element 12 from the first position to the second position. In the second operating state, however, the pump 14 delivers any oil that may have been absorbed into the oil chamber 36 out of the oil chamber 36 via the connecting line 26. In other words, in the second operating state, the pump 14 creates a vacuum in the oil chamber 36. This allows or causes the actuating element 12 to move from the second position to the first position. In particular, in the second operating state, the actuating element 12 is drawn from the second position to the first position. To achieve particularly advantageous operation, the actuating element 12 has a first sealing surface 38, especially on its end face 34, and the housing 18 has a second sealing surface 40 corresponding to the first sealing surface 38, which is also referred to as the contact surface. In the first position, the sealing surface 38 rests directly against the sealing surface 40, thereby sealing the actuating element 12 directly against the housing 18. In other words, in the second operating state, the first sealing surface 38 can be moved into direct, sealing contact with the second sealing surface 40, thus sealing the actuating element 12 directly against the housing 18. This prevents the pump 14 from drawing in air in the second operating state, i.e., from drawing air between the actuating element 12 and the housing 18.Thus, air intake can be avoided when the pump 14 is operated in both directions of rotation or when its direction of rotation is reversed. Due to the geometric design of the actuating element 12, which is intended to create the sealing surface 38, the actuating function is at least almost hermetically sealed, particularly when the pump 14 is operated in the second operating state, i.e., in normal operation, where the actuating element 12 is not actuated (i.e., when no actuating function for the actuating element 12 is used). This means that the actuating element 12 is sealed against the housing 18 by means of the sealing surfaces 38 and 40, without the need for any additional sealing elements. Air intake is also prevented by any wear of the guide for the actuating element 12, which is guided within the housing 18.In particular, the connecting line 26, which functions or is designed as a suction line in the second operating state, can be hermetically sealed without the need for any additional sealing elements. Thus, a hydraulic check valve is integrated into the actuating element 12. In other words, the sealing surfaces 38 and 40, and therefore the actuating element 12 and the housing 18, function as a check valve which, particularly in the second operating state, blocks flow towards the pump 14 and opens in the opposite direction, i.e., towards the actuating element 12, and particularly in the first operating state. Furthermore, a mechanical stop in an actuating geometry, particularly of the actuating element 12, is designated 42 in the figure. The respective sealing surfaces 38 and 40 can have different contours. In other words, different contours for the respective sealing surfaces 38 and 40 are conceivable. Reference symbol list 10 Parking lock 12 Actuating element 14 Pump 16 Double arrow 18 Housing 20 Reservoir 22 Double arrow 24 Consumer 26 Connecting line 28 Double arrow 30 Filter 32 Check valve 34 End face 36 Oil chamber 38 First sealing surface 40 Second sealing surface 42 Mechanical stop

Claims

Transmission element for a motor vehicle, comprising at least one hydraulic actuating element (12) which is hydraulically movable at least from a first position to a second position, and comprising an electric pump (14) by means of which a hydraulic fluid is conveyed to the actuating element (12) and thereby the actuating element (12) is hydraulically movable from the first position to the second position, wherein the electric pump (14) is operable in a first operating state in which the hydraulic fluid is conveyed by means of the pump (14) in a first direction and thereby to the actuating element (12), whereby the actuating element (12), which is movable relative to a housing (18) of the actuating element (12) between the positions, is hydraulically movable from the first position to the second position;- the electric pump (14) is operable in a second operating state in which the hydraulic fluid is to be conveyed by means of the pump (14) in a second direction opposite to the first direction and thereby away from the actuating element (12) and from a reservoir (20) and towards at least one consumer (24) provided in addition to the actuating element (12), whereby the consumer (24) can be supplied with the hydraulic fluid; - the actuating element (12) has a first sealing surface (38);and the housing (18) of the actuating element (12) has a second sealing surface (40) corresponding to the first sealing surface (38), with which the first sealing surface (38) can be moved into a sealing position by the second operating state, whereby the actuating element (12) can be sealed directly against the housing (18), characterized in that the actuating element (12) has its first sealing surface (38) on an end face (34) of the actuating element (12), wherein the first sealing surface (38) is a guide-direction oriented sealing surface. Gear element according to claim 1, characterized in that the electric pump (14) can be operated in a first direction of rotation in the first operating state and in a second direction of rotation opposite to the first direction of rotation in the second operating state. Gear element according to one of the preceding claims, characterized in that the gear element is designed as a parking lock (10). Gear element according to claim 3, characterized in that by moving the actuating element (12) into the second position a locking element for a positive locking of the gear element designed as a parking lock (10) can be brought into a first position in which the locking element is unlocked. Gear element according to one of the preceding claims, characterized in that the sealing surfaces (38, 40) are each curved, in particular spherically shaped. Gear element according to one of the preceding claims, characterized in that the sealing surfaces (38, 40) are each conically shaped.

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