Actuating device for a switching element and transmission

Abstract

Actuating device (25) for actuating at least one switching element (A, B, C) of a vehicle, with at least one hydraulic switching cylinder arranged inside a transmission shaft (1), - with which at least one sliding sleeve (2, 3) can be selected and actuated to actuate at least one of the switching elements (A, B, C), - wherein each switching element (A, B, C) is connected to the transmission shaft (1) in a rotationally fixed manner, wherein the switching cylinder is mounted on the housing side with at least one piston rod (4) and the at least one associated sliding sleeve (2, 3) independently of the transmission shaft (1), and - wherein the piston rod (4) of the switching cylinder is rotatable for selecting the respective sliding sleeve (2, 3) and axially movable for actuating the sliding sleeve (2, 3).

Description

[0001] The present invention relates to an actuating device for actuating at least one shifting element of a vehicle and to a transmission with an actuating device.

[0002] For example, from the publication DE 37 11 490 A1, a gearshift device for a synchronizer-free step-change transmission of vehicles is known. The step-change transmission comprises a transmission shaft on which several rotatably mounted gear wheels are provided. For shifting the gear wheels, an axially displaceable shifting claw is provided, which is connected to the transmission shaft. To shift the gear wheels, the shifting claw is displaced axially in order to connect the associated gear wheel to the transmission shaft in a rotationally fixed manner. The axial displacement of the shifting claw is effected by a hydraulic adjustment device arranged within the transmission shaft.The adjustment device comprises an actuating piston assembly consisting of two individual pistons, which is axially displaceably mounted in a central cylinder bore of the transmission shaft and has pressurization chambers on its opposite end faces, which can be pressurized with pressurized fluid via pressure fluid supply lines. The actuating piston assembly is connected to the shift claw via a connecting bolt that penetrates the transmission shaft diametrically and is held in a radial bore of the shift claw. Thus, both the shift claw or sliding sleeve and the actuating piston assembly rotate at the transmission shaft speed. A disadvantage of this type of actuation is that a rotary transmission for the pressure fluid supply is required. This is structurally complex and cost-intensive.

[0003] Document DE 10 2006 049 278 A1 discloses another method for actuating a switching element or connecting device, by means of which a transmission shaft can be connected in a rotationally fixed manner to a gearwheel mounted rotatably on the transmission shaft. The actuating force of the actuator, designed as an electric motor, can be transmitted within the transmission shaft via a mechanical transmission device from the actuator to the connecting device. A selection device is assigned to the transmission device, by means of which a connection can be established between the transmission device and a selected connecting device.

[0004] DE 10 2016 201 719 A1 discloses a shifting device for a multi-stage manual transmission with a shift shaft that is arranged coaxially within a locking shaft designed as a hollow shaft, in a rotationally fixed and axially displaceable manner. The shift shaft has a servo-assistance device inside it that amplifies the manually applied shifting force.

[0005] DE 10 2006 049 281 A1 presents a device for actuating a gear wheel of a transmission device designed as a loose wheel, which is rotatably mounted and has an actuator arranged at least partially in the interior of the shaft and operable via a fluid pressure medium.

[0006] The present invention is based on the object of proposing an actuating device for at least one shifting element of a vehicle and a transmission with an actuating device which realizes a hydraulic axial movement of several shifting elements as cost-effectively and structurally simply as possible.

[0007] This object is achieved according to the invention by the features of patent claim 1 and 13, respectively, wherein advantageous and claimed embodiments result from the subclaims and the description as well as the drawings.

[0008] Accordingly, an actuating device for actuating at least one shifting element of a vehicle is proposed, in which at least one hydraulic shifting cylinder is arranged inside a transmission shaft, with which at least one sliding sleeve or the like can be selected and actuated for actuating at least one shifting element. The shifting element is connected to the transmission shaft in a rotationally fixed manner. The shifting cylinder is mounted on the housing side with at least one piston rod and the at least one associated sliding sleeve, independently of the transmission shaft. Furthermore, the piston rod of the shifting cylinder is rotatable for selecting the respective sliding sleeve and axially movable for actuating the sliding sleeve.

[0009] The actuating device according to the invention can therefore easily actuate one or more shift claws or synchronizers as shift elements on a transmission shaft from the interior of the shaft with the simplest possible design and minimal installation space requirements. Hydraulic actuation offers the advantage that the medium or pressure medium present in the transmission can be used for this purpose. Consequently, no additional electric motor is required to generate the axial movement of the piston rod. In contrast to the known hydraulic actuation, the key advantage is that the hydraulic shift cylinder is mounted on the housing side inside the transmission shaft, independently of the transmission shaft. This significantly reduces the hydraulic effort.A further difference is that the sliding sleeve, which is otherwise encompassed by the switching element and rotates at the speed of the transmission shaft, is part of the switching cylinder in the actuating device according to the invention and is therefore also mounted on the housing side and is non-rotatable.

[0010] According to an advantageous development of the invention, the piston rod can each have at least one actuating element for selecting and actuating the associated sliding sleeve, and the respective sliding sleeve has a corresponding link contour for the associated actuating element, so that the selection movement of the piston rod initially selects a sliding sleeve to be actuated, and the axial movement of the piston rod can actuate the associated switching element. The actuating element is structurally simple, for example, as cam elements which protrude from the circumference of the piston rod and, when aligned congruently, can penetrate axially through the link contour or, in the simplest case, through a passage opening in the non-selected sliding sleeve, so that only the selected sliding sleeve is actuated.In this way, the proposed actuating device enables the control of as many switching elements as possible with the piston rod per axial movement direction of the piston rod.

[0011] To further minimize hydraulic effort, a further development of the invention can provide for each sliding sleeve to be assigned at least one guide sleeve for axially and radially guiding the sliding sleeve inside the transmission shaft, with the sliding sleeve and the guide sleeve being arranged coaxially with the piston rod in a rotationally fixed manner. The guide sleeves serve not only for axial support but also as a switching cylinder housing for the at least one piston provided on the piston rod.

[0012] In order to transmit the movement of the sliding sleeves to the at least one associated shifting element, an advantageous embodiment of the present invention provides that each sliding sleeve mounted on the housing side is assigned a guide groove or the like running around its outer diameter for guiding at least one driver or the like of the shifting element to be actuated, rotating at the transmission shaft speed. Actuation of the shifting element is achieved by axial movement of the sliding sleeve. In this way, the axial movement is transmitted to the driver, which in turn is part of the shifting element.

[0013] The actuating device according to the invention is particularly suitable for actuating shifting elements in dual-clutch transmissions, in which the shifting elements, such as claw clutches or synchronizers of a sub-transmission, are each located on a separate shaft. However, use in a manual transmission or other automatic transmissions is also possible. Accordingly, a transmission with the actuating device according to the invention is also claimed.

[0014] The present invention is further explained below with reference to the drawings. They show: Fig. 1 a sectional view of a possible embodiment of an actuating device according to the invention on a transmission shaft with several switching elements; Fig. 2 a three-dimensional view of the actuating device with a hydraulic switching cylinder; Fig. 3 an enlarged detail according to Fig. 2; Fig. 4 a cross-section through the switching cylinder of the actuating device in the area of ​​a non-selected sliding sleeve of the switching cylinder; Fig. 5 a cross-section through the switching cylinder of the actuating device in the area of ​​a selected sliding sleeve; Fig. 6 a three-dimensional view of the sliding sleeve; Fig. 7 a front view of the sliding sleeve; Fig. 8 a side view of the sliding sleeve; Fig. 9 a three-dimensional view of a guide sleeve of the switching cylinder; Fig. 10 a side view of the guide sleeve; Fig. 11 a front view of the guide sleeve; Fig. 12 a three-dimensional schematic view of the piston rod; and Fig. 13 a schematically indicated gear with the schematically indicated actuating device.

[0015] In the Fig. 1 to 12 show various views of a possible embodiment variant of an actuating device 25 for actuating at least one switching element A, B, C of a vehicle by way of example, wherein the transmission components known per se to the person skilled in the art are not further designated. Fig. 13 shows an embodiment in which any gear 26 includes the actuating device 25.

[0016] The actuating device 25 comprises at least one hydraulic shift cylinder arranged inside a transmission shaft 1, with which at least one sliding sleeve 2, 3 can be selected and actuated for actuating at least one shift element A, B, C. The shift element A, B, C is connected in a rotationally fixed manner to the transmission shaft 1 in order to connect an associated gear wheel in a rotationally fixed manner to the transmission shaft 1 when the shift element A, B, C is engaged. The shift cylinder is mounted on the housing side with a piston rod 4 and the two sliding sleeves 2, 3 provided, for example, in the exemplary embodiment shown, independently of the transmission shaft 1. The piston rod 4 of the shift cylinder is rotatable for selecting the respective sliding sleeves 2, 3 and axially movable for actuating the selected sliding sleeve 2, 3.

[0017] In Fig. 1 shows a sectional view of the actuating device 25 according to the invention on a transmission shaft 1 of the transmission 26 of a vehicle for the exemplary actuation of three switching elements A, B, C. The piston rod 4 of the switching cylinder has for selecting or preselecting and axially moving the first and second sliding sleeves 2, 3, as can be seen from the individual part view according to Fig. 12, two pairs of cam elements 5, 6; 7, 8 each serve as actuating elements for each sliding sleeve 2, 3. Each pair of cam elements 5, 6; 7, 8 comprises two cam elements arranged at an identical angle, e.g., 180 degrees, on the circumference of the piston rod 4. The pairs of cam elements 5, 6 of the first sliding sleeve 2 and the pairs of cam elements 7, 8 of the second sliding sleeve 3 are offset from one another in the circumferential direction on the piston rod 4 at a predetermined angle, so that the rotational movement of the piston rod 4 allows separate selection of the sliding sleeves 2, 3.

[0018] This is achieved in particular in that the cam element pairs 5, 6; 7, 8 of the non-selected sliding sleeve 2, 3 axially penetrate through a corresponding passage opening 14 on the first sliding sleeve 2 or through a corresponding passage opening 15 on the second sliding sleeve 3 as a link contour on the non-selected sliding sleeve 2, 3, while the cam element pairs 5, 6; 7, 8 of the selected sliding sleeve 2, 3 axially bear against the sliding sleeve 2, 3 and carry it axially through the axial movement of the piston rod 4.

[0019] In Fig. 4, for example, shows the penetration of the non-selected sliding sleeve 2, 3 of the cam element pairs 5, 6; 7, 8, while in Fig. 5 the engagement of the cam element pairs 5, 6; 7, 8 on the selected sliding sleeve 2, 3 is shown.

[0020] To ensure the axial movement of the sliding sleeves 2, 3, each sliding sleeve 2, 3 is assigned a guide sleeve 9, 10 for axial guidance and for a rotationally fixed arrangement inside the transmission shaft 1. The sliding sleeves 2, 3 and the associated guide sleeves 9, 10 are arranged coaxially to the piston rod 4 in a rotationally fixed manner. Consequently, the guide sleeves 9, 10 are fixed to the housing, while the sliding sleeves 2, 3 are guided axially in the guide sleeves 9, 10.

[0021] The transmission shaft 1 rotates at the corresponding transmission shaft speed, with the shifting elements A, B, and C, exemplified here as shifting dogs 11, 20 with corresponding drivers 18, 19, also being connected to the transmission shaft 1 and rotating at the transmission shaft speed. Thus, the first shifting element A comprises the shifting dog 11, to which the driver 18 is assigned, and the second and third shifting elements B, C comprise the common shifting dog 20, to which the driver 19 is assigned.

[0022] As an operative connection between the sliding sleeves 2, 3 and the switching elements A, B, C, each sliding sleeve 2, 3 has a guide groove 16, 17 running around its diameter for guiding the associated rotating drivers 18, 19 of the switching element A, B, C to be actuated. A pin with a circular, square, or similar cross-section, or even a fork or the like, can be provided as the driver 18, 19.

[0023] In this embodiment shown, the shift claw 11 of the first shift element A is associated with the driver 18 of the first sliding sleeve 2, while the shift claw 20 of the second and third shift elements B, C is associated, as a quasi-double shift element, with the associated driver 19 of the second sliding sleeve 3. In this way, three shift elements A, B, C can be actuated with the actuating device 25.

[0024] To move the piston rod 4 axially, this illustrated embodiment provides, by way of example, that each end of the piston rod 4 is assigned a piston 12, 13, which can be pressurized with a medium, for axially actuating the piston rod 4 in one direction each. It would also be conceivable for a double-acting piston to be assigned to one end of the piston rod 4 for axial movement in both axial directions.

[0025] Because the piston rod 4 is assigned the first piston 12 for axial actuation of the piston rod 4, the piston rod 4 can be moved in the plane of the drawing at Fig. 1 can be moved axially to the right when pressure is applied, while the piston rod 4 can be moved axially to the right when pressure is applied to the second piston 13 in the plane of the drawing according to Fig. 1 can be moved to the left.

[0026] By appropriate preselection, i.e., by appropriate rotation of the piston rod 4 and the resulting rotation of the cam element pairs 5, 6, the first sliding sleeve 2 is preselected, for example, by the first cam element pair 5 abutting the first sliding sleeve 2. If the piston rod 4 is now moved to the right by appropriate pressure being applied to the first piston 12, the sliding sleeve 2 is also moved to the right and is thereby moved by the driver 18 and the associated switching claw 11, so that the first switching element A is opened.When the cam element pair 6 comes into contact with the first sliding sleeve 2 through appropriate preselection via the piston rod 4 and the second piston 13 is pressurized so that the piston rod 4 moves to the left, the selected sliding sleeve 2 is also moved to the left, so that the driver 18 with the switching claw 11 of the first switching element A is also moved to the left, whereby the first switching element A is closed and comes into positive engagement with the associated gear wheel, so that this is connected in a rotationally fixed manner to the transmission shaft 1. The actuation of the second and third switching elements B, C works in the same way via the associated switching claw 20 with the driver 19, in which the cam element pair 7, 8 is brought into contact with the second sliding sleeve 3.Because the cam element pairs 5, 6 of the first sliding sleeve 2 and the cam element pairs 7, 8 of the second sliding sleeve 3 are offset from one another on the circumference of the piston rod 4, i.e. are not arranged congruently, when the second sliding sleeve 3 is selected, the cam element pairs 5, 6 of the first sliding sleeve 2 pass through the passage opening 14 of the first sliding sleeve 2, while the cam element pairs 7, 8 of the second sliding sleeve 3 are in contact with the second sliding sleeve 3 in order to realize only the axial movement of the selected second sliding sleeve 3.

[0027] In this way, several switching elements A, B, C can be actuated in the simplest way with the proposed actuating device 25, in that the cam element pairs 5, 6; 7, 8 of the provided sliding sleeves 2, 3 are each offset from one another on the circumference of the piston rod 4 in a predetermined manner, i.e. at a predetermined angle to one another.

[0028] As can be seen in particular from the Fig. 2 to 8, each sliding sleeve 2, 3 has a plurality of axial recesses 21, 22 as longitudinal grooves on the circumference, into which corresponding axial projections 23, 24 of the Fig. 9 to 11, can be inserted in a form-fitting or axial manner, thus ensuring anti-rotation protection. This also has the advantage that radial guidance of the sliding sleeves 2, 3 among themselves and in the guide sleeves 8, 9 is achieved through the interlocking of the axial recesses 21, 22 and the axial projections 23, 24. This creates a centering effect, ensuring the necessary radial clearance between the sliding sleeves 2, 3 and the guide sleeves 9, 10 on the one hand, and the rotating gear shaft 1 on the other.

[0029] An anti-rotation lock of the sliding sleeves 2, 3 by the guide sleeves 9, 10 can also be realized, for example, by means of a profile toothing or the like.

[0030] Furthermore, in particular Fig. 8 shows the guide groove 16 of the first sliding sleeve 2 for the associated driver 18 of the shift claw 11 of the first shifting element A or the guide groove 17 of the second sliding sleeve 3 for the associated driver 19 of the shift claw 20 of the second and third shifting elements B, C. The guide groove 16, 17 is a groove running around the outer circumference.

[0031] The selection movement or rotation of the piston rod 4 can be realized by a hydraulic or electromechanical actuator. If necessary, the rotation of the piston rod 4 can be realized by an actuator present in the transmission 26, for example, a clutch actuator or the like. Reference symbol 1 gear shaft 2 first sliding sleeve 3 second sliding sleeve 4 piston rod 5, 6 Cam element pair of the first sliding sleeve 7, 8 Cam element pair of the second sliding sleeve 9 first guide sleeve 10 second guide sleeve 11 Switching claw of the first switching element 12 first piston 13 second piston 14 Passage opening of the first sliding sleeve 15 Passage opening of the second sliding sleeve 16 Guide groove of the first sliding sleeve 17 Guide groove of the second sliding sleeve 18 Driver or driver pin of a first switching element 19 Driver or driver pin of a second and third switching element 20 Switching claw of the second and third switching element 21 axial recesses of the first sliding sleeve 22 axial recesses of the second sliding sleeve 23 axial projections of the first guide sleeve 24 axial projections of the second guide sleeve 25 Actuating device 26 gearboxes A first switching element B second switching element C third switching element

Claims

[1] Actuating device (25) for actuating at least one switching element (A, B, C) of a vehicle, with at least one hydraulic switching cylinder arranged inside a transmission shaft (1), - with which at least one sliding sleeve (2, 3) can be selected and actuated to actuate at least one of the switching elements (A, B, C), - wherein each switching element (A, B, C) is connected to the transmission shaft (1) in a rotationally fixed manner, wherein the switching cylinder is mounted on the housing side with at least one piston rod (4) and the at least one associated sliding sleeve (2, 3) independently of the transmission shaft (1), and - wherein the piston rod (4) of the switching cylinder is rotatable for selecting the respective sliding sleeve (2, 3) and axially movable for actuating the sliding sleeve (2, 3). [2] Actuating device (25) according to claim 1, characterized bythat the piston rod (4) has at least one actuating element (27) for selecting and actuating the associated sliding sleeves (2, 3) and that each sliding sleeve (2, 3) has a link contour corresponding to the sliding sleeves (2, 3) for the associated actuating element (27). [3] Actuating device (25) according to claim 2, characterized by that each sliding sleeve (2, 3) is assigned two pairs of cam elements (5, 6; 7, 8) arranged congruently to one another on the piston rod (4) at an axial distance as an actuating element (27), wherein each pair of cam elements (5, 6; 7, 8) has opposite cam elements (28) on the circumferential region of the piston rod (4). [4] Actuating device (25) according to claim 3, characterized bythat the respective cam element pairs (5, 6; 7, 8) of the piston rod (4) bear against the selected sliding sleeve (2, 3) for axial displacement, while the cam element pairs (5, 6; 7, 8) of the non-selected sliding sleeve (2, 3) are arranged offset in the circumferential direction of the piston rod (4) in such a way that these cam element pairs (5, 6; 7, 8) axially penetrate through a passage opening (14, 15) as a link contour on the non-selected sliding sleeve (2, 3). [5] Actuating device (25) according to one of the preceding claims, characterized by that each sliding sleeve (2, 3) is assigned at least one guide sleeve (9, 10) for axially guiding the sliding sleeve (2, 3) in the interior of the transmission shaft (1), wherein the sliding sleeve (2, 3) and the guide sleeve (9, 10) are arranged coaxially to the piston rod (4) in a rotationally fixed manner. [6] Actuating device (25) according to claim 5, characterized bythat each sliding sleeve (2, 3) has a plurality of axial recesses (21, 22) on the circumference, into which corresponding axial projections (23, 24) of the guide sleeves (9, 10) can be axially inserted. [7] Actuating device (25) according to one of the preceding claims, characterized by that each sliding sleeve (2, 3) is assigned a guide groove (16, 17) running around the outer diameter for guiding at least one driver (18, 19) of the at least one switching element (A, B, C) to be actuated, said driver rotating at the speed of the transmission shaft, wherein an associated gear wheel can be connected in a rotationally fixed manner to the transmission shaft (1) by axial movement of the sliding sleeve (2, 3) and the associated axial movement of the driver (18, 19) of the switching element (A, B, C). [8] Actuating device (25) according to one of the preceding claims, characterized bythat each end of the piston rod (4) is assigned a piston (12, 13) which can be pressurized with pressure medium for axially moving the piston rod (4) in one direction each. [9] Actuating device (25) according to one of claims 1 to 7, characterized by that a double-acting piston (12, 13) for axially moving the piston rod (4) in both directions is assigned to one end of the piston rod (4). [10] Actuating device (25) according to claim 8 or 9, characterized by that each guide sleeve (9, 10) is designed as a switching cylinder housing for axially guiding the associated piston (12, 13). [11] Actuating device (25) according to one of the preceding claims, characterized by that a hydraulic or electromechanical actuator is provided for rotating the piston rod (4). [12] Actuating device (25) according to one of the preceding claims, characterized by , that the piston rod (4) is assigned a first piston (12) for axially moving the piston rod (4) in a first axial direction, wherein the first piston (12) is assigned a first guide sleeve (9), wherein the first guide sleeve (9) is positively connected to a first sliding sleeve (2) for axially guiding the first sliding sleeve, with which a first switching element (A) can be actuated, wherein a second sliding sleeve (3) for actuating a second and a third switching element (B, C) is arranged on a side of the first sliding sleeve (2) facing away from the first guide sleeve (9) depending on the axial direction of movement of the piston rod (4), wherein the second sliding sleeve (3) which is axially movable via the piston rod (4) is positively connected to the first sliding sleeve (2), wherein a second guide sleeve (10) is arranged on a side of the second sliding sleeve (3) facing away from the first sliding sleeve (2), which second guide sleeve is positively connected to the second sliding sleeve (3), and wherein within the second guide sleeve (10) a second piston (13) is assigned to the piston rod (4) for axially moving the piston rod (4) in a second axial direction. [13] Gearbox (26) for a motor vehicle, characterized by an actuating device (25) according to one of claims 1 to 12.

Images