System for operating a gearbox for a motor vehicle

Abstract

The invention relates to a system (1) for operating a gearbox (100), comprising: a first shaft (2) having a first longitudinal axis (X2); a first actuator assembly (4) operatively connected to the first shaft (2); a second shaft (6) having a second longitudinal axis (X6); a second actuator assembly (8) operatively connected to the second shaft (6); and a plurality of engagement elements (10, 12, 14) rotationally connected to the second shaft (6); the first shaft (2) is hollow, mounted on the second shaft (6) and axially movable relative to the second shaft (6), and the plurality of engagement elements (10, 12, 14) are further translationally connected to the first shaft (2) and axially movable with the first shaft along the first longitudinal axis (X2) and relative to the second axis (X6). The first shaft and the second shaft can be operated independently of each other to perform the movement of selecting and engaging the gear of the gearbox (100).

Description

Technical Field

[0001] The present invention relates to a system for operating a gearbox, in particular an automatic gearbox for selecting and engaging a gear. Background Art

[0002] Current control solutions for operating gearboxes with XY-type movements (i.e. in which the operating system affects the selection and engagement of movements along the same movement coordinates as characterize the movements in a completely manually operated system) are characterized by the presence of a kinematic chain that is very cumbersome and, in particular, makes its installation in a three-shaft gearbox (e.g. a dual-clutch gearbox with two layshafts) very problematic.

[0003] Furthermore, the presence of linear or rotary actuators coupled to the operating system or the housing of the gearbox makes hybridization of the transmission by adding an electric motor engaged with the main shaft extremely problematic, if not impossible. Summary of the Invention

[0004] The object of the present invention is to provide a system for operating a gearbox with XY type movement which will be very compact and easy to install and will enable the installation of other accessories on the transmission, such as an electric motor for mild hybridization of the vehicle.

[0005] The objects of the invention are achieved by an operating system and a gearbox having the features forming the subject matter of the subsequent claims, which form an integral part of the technical teaching provided herein in relation to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention will now be described with reference to the accompanying drawings, which are provided by way of non-limiting example only, and in which:

[0007] - Figure 1 is a perspective view of an operating system according to the present invention;

[0008] - Figure 2 and Figure 1 Similar, but with some of the components removed for clarity;

[0009] - Figure 3 is a longitudinal sectional view of an operating system according to the present invention;

[0010] - Figure 4 is an overall view of a gearbox according to the present invention with some components removed; and

[0011] - Figure 5 is a detailed view of the functional coupling between the operating system according to the invention and the gearbox itself. DETAILED DESCRIPTION

[0012] See Figures 1 to 3 , numeral 1 generally designates a system for operating a transmission. The operating system 1 is configured for selecting and engaging forward and reverse gears of the transmission and can optionally be configured (as will be described later) for controlling a mechanism for locking the transmission, which mechanism achieves a park position of the transmission itself.

[0013] The system 1 includes a first shaft 2 or outer shaft having a first longitudinal axis X2, and a first actuator assembly 4 operatively connected to the first shaft 2. The system 1 further includes a second shaft 6 or inner shaft having a second longitudinal axis X6, and a second actuator assembly 8 operatively connected to the shaft 6. The operating system 1 further includes a plurality of engagement elements 10, 12, 14 rotationally connected to the second shaft 6 and configured for engagement with a drive element of the gearbox.

[0014] The first shaft 2 is a hollow shaft and is preferably mounted on the second shaft 6 in such a way that the respective axes X2 and X6 coincide with each other.

[0015] Furthermore, the inner shaft 6 is preferably shaped to have a non-completely circular cross-section (eg, shaped like a D) so as to be configured for positive coupling with the engagement elements 10 , 12 , 14 .

[0016] In the preferred embodiment shown in the figures, each element 10, 12, 14 is provided as a bushing element comprising a collar 10R, 12R, 14R with a central hole having the same shape as the cross section of the shaft 6 (here shaped like D) for torsionally connecting by form fit, and radial engagement fingers 10F, 12F, 14F provided integrally with the collar itself. The form fit between the engagement elements 10, 12, 14 is axially slidable.

[0017] See especially Figure 3 The above solution results in an outer shaft 2 having a structure formed of segments. In particular, in this embodiment, the outer shaft 2 comprises a first segment 18 and a second segment 20 - both provided in the form of tubular elements - which are coupled to the coupling elements 10, 12, 14 and are particularly joined together by means of the coupling element 12. The coupling is preferably provided by an interference fit between the collars 10R, 12R, 14R and the corresponding segments 18, 20.

[0018] The structure of the actuator assemblies 4, 8 and the manner in which they impart motion to the shafts 2, 6 will now be described in detail. Figure 2 and 3The first actuator assembly 4 comprises a first rotary actuator 22 having an output shaft 24 rotatable about a rotation axis Y24 orthogonal to the axes X2, X6. A pinion 26 is mounted on the output shaft 24, or provided integrally therewith, or otherwise rotationally connected thereto, and meshes with a rack 28, which is axially movable in a direction parallel to the axes X2, X6.

[0019] The rack 28 is connected to the shaft 2 in axial translation along the axes X2, X6 (i.e., it translates with the shaft 2) and is coupled thereto in particular by means of a first shoulder ring 30 and a second shoulder ring 32, which are provided integrally with the rack 28 and are supported on the coupling element 12. The shoulder rings are mounted with a certain play relative to the sectors 18, 20 of the shaft 2 in such a way that the shaft can rotate freely relative to the shoulder rings (and is thus supported).

[0020] Optionally, a third ring 34 is provided which has the function of further rotational support for the shaft 2. The shaft 2 is thus fixed in translation along the axes X2, X6 relative to the rack 28, but free to rotate about the axis itself relative to the rack 28 itself, and in particular relative to the rings 30, 32, 34.

[0021] The second actuator assembly 8, in turn, includes a second rotary actuator 36 having an output shaft 38 rotatable about an axis X38 orthogonal to an axis Y24 parallel to axes X2, X6. A pinion 40 is mounted on, integrally provided with, or otherwise rotationally connected to the output shaft 38, providing an input element of a transmission (particularly a gear train transmission) that transmits motion from the actuator 36 to the shaft 6. The pinion 40 meshes with a first gear wheel 42, in particular with a first toothing 44 of the first gear wheel having a first diameter. The toothing 44 may extend along an arc that does not cover the entire circumference around the respective axis of rotation X42 (due to the limited angular range covered by the toothing 44 during operation), or along the entire circumference. A second toothing 46 of the gear wheel 42, coaxial with the toothing 44, in turn, meshes with a toothed sector 48 that defines the output element of the transmission in question. The toothed sector 48 is rotationally connected to the shaft 6 by means of a hub 50 which has a coupling bore with the same cross section as the shaft 6 and thus provides a form fit therewith.

[0022] According to an advantageous aspect of the invention, the second actuator assembly 8 is carried by a mounting flange 52 comprising a seat 54 for housing the rotary actuator 36 and an extension 56 integral with the flange 52 itself. The extension 56 carries a bushing 57 which itself serves as a rotary bearing for the output shaft 24 of the actuator assembly 4. The mounting flange 52 also comprises an annular extension 58 which fits around the shaft 6 and is able to accommodate the axial travel of the outer shaft 2.

[0023] In various possible embodiments of the present invention, the rotary actuators 22 and 36 are preferably provided as rotary motors.

[0024] See Figure 4 , numeral 100 denotes a gearbox according to the present invention as a whole. Gearbox 100 itself may be of known type, but—according to the present invention—in any case incorporates an operating system 1. Gearbox 100 comprises a main shaft 102, rotatable about an axis Y102 and carrying a plurality of gear wheels rigidly connected in rotation therewith, and further comprises a first countershaft 104 and a second countershaft 106, rotatable about axes Y104, Y106, respectively, parallel to each other and to axis Y102. Each of countershafts 104, 106 carries a respective plurality of idler gear wheels that mesh with (at least) corresponding gear wheels on main shaft 102 to define the forward and reverse gears of the gearbox.

[0025] Furthermore, each of the two layshafts 104, 106 supports an output pinion which meshes with the ring gear of the differential DIFF which is rotatable about the axis YD. The idler gears on the layshafts 104, 106 can be driven by means of Figure 3 and 5 The fork drive elements F1, F2, F3, F4 shown in FIG. 1 selectively connect in rotation to the respective layshafts (for the sake of brevity, these elements will be referred to as "fork / forks" hereinafter). Each of the forks F1-F4 has a respective control seat CF1, CF2, CF3, CF4 that can be selectively (and thus) engaged by the engagement elements 10, 12, 14.

[0026] See Figures 3 to 5 , forks F1 and F3 can slide along their respective support rods R1 / 3, in particular along their axes YF1 / 3 parallel to the axes of the main shaft and the secondary shaft, while forks F2 and F4 can slide along their corresponding support rods R2 / 4, in particular along their axes YF2 / 4 parallel to the axes of the main shaft and the secondary shaft and parallel to the axis YF13.

[0027] As in Figure 3 、 Figure 4 And secondly Figure 5As can be seen in FIG, the fork groups F1, F3 and F2, F4 slide axially in parallel directions on opposite sides of the gearbox 100. Figure 3 Visible in the illustration of FIG are the control seats CF1 - CF4 and in particular the distribution of the selection planes due to the staggering of the seats CF1 - CF4 in the direction of the axes X2 and X6 .

[0028] As in Figure 4 As can be seen in the figure, the operating system 1 is mounted on the gearbox 100 in such a manner that the axes X2 and X6 are transverse (here, orthogonal) to the axes Y102, Y104, and Y106 of the primary and secondary shafts. Furthermore, an electric motor 200 can be coupled to the gearbox 100 for mild hybridization of the vehicle. The electric motor 200 has an output shaft with a pinion that meshes with one of the gears carried by the primary shaft 102 via an idler ring gear 202.

[0029] The operation of the operating system 1 and the transmission 100 will be described below.

[0030] The shafts 2 and 6 respectively perform the functions of selecting a gear of the gearbox 100 and engaging the gear itself. Thus, the rotary actuator 22 is a selection actuator, while the rotary actuator 36 is an engagement actuator.

[0031] The selection operation is provided by driving shaft 2 by means of actuator 22, causing it to perform an axial stroke along axes X2, X6. Pinion 26 meshes with rack 28, causing it to translate axially along axes X2, X6, and this same axial translation is also transmitted to shaft 2, which is fixed relative to the rack itself, and to coupling elements 10, 12, 14, which translate together with shaft 2 due to the fact that they can slide axially due to the form fit with shaft 6. The result of the selection operation is the alignment (and therefore coupling) of radial fingers 10F, 12F, 14F of one of the coupling elements 10, 12, 14 with the control seat CF1, CF2, CF3, CF4, depending on the gear to be engaged.

[0032] The engagement operation follows the selection operation and is provided by means of actuator 36: pinion 40 meshes with toothing 44 of (idling) gear wheel 42, and toothing 46 of gear wheel 42 meshes with toothed sector 48, transmitting the rotational movement to shaft 6 by means of hub 50. The rotational movement of shaft 6 causes the engagement elements 10, 12, 14 (and shaft 2 itself) to rotate, and thus the forks F1, F2, F3, F4 selected for engagement to translate axially.

[0033] Unlike known types of operating systems, the overall dimensions of system 1 in the direction of the axes X2, X6 are clearly constrained by the fact that the axial travel of the mobile elements that move axially in system 1 is at most equal to the set of selection planes. Moreover, since the selection and engagement movements are assigned to two separate axes (2, 6) that are active relative to each other and driven independently, the selection travel does not result in dragging of the components responsible for the engagement movement.

[0034] Thus, it is possible to free the gearbox 100 from the need for a large housing for the control components and / or a particularly long operating system that would not allow, for example, the installation of the electric motor 200 .

[0035] In addition, it should be noted that - as in Figure 4 and Figure 5 As shown in , it is possible to envisage that the engagement element 10 will control a parking device P of the gearbox 100. In the embodiment shown here, the parking device P comprises a pawl P1 which oscillates about an axis YP1 parallel to the axis Y106 and is elastically resisted to rotation by means of a torsion spring PS.

[0036] The pawl P1 is configured to engage with a sprocket P2 connected in rotation to the spindle 106. The engagement is provided by engaging the pawl P1 in the teeth of the sprocket P2, this operation being achieved by means of a slider P3 controlled by a mobile element P4 movable along an axis YP4 parallel to the axis YP1 and drivable by the rotation of the engagement element 10.

[0037] Moving element P4 drives slider P3, which is equipped with rollers. This slider passes over pawl P1, causing it to rotate toward the teeth of sprocket P2 via a cam action. Essentially, slider P3 acts as a cam, while pawl P1 acts as a tappet. Furthermore, slider P3 is secured to gearbox 100 via a securing plate P5.

[0038] Of course, the details of construction and of the embodiments may vary widely with respect to what is described and illustrated herein, without thereby departing from the scope of the invention as defined by the appended claims.

Claims

1. A system (1) for operating a gearbox (100), comprising: - a first shaft (2) having a first longitudinal axis (X2); - a first actuator assembly (4) operatively connected to said first shaft (2); - a second shaft (6) having a second longitudinal axis (X6); - a second actuator assembly (8) operatively connected to the second shaft (6); and - a plurality of engagement elements (10, 12, 14) rotationally connected to the second shaft (6), wherein each engagement element (10, 12, 14) is rotationally connected to the second shaft (6) by means of a positive coupling of the axial sliding type; in: - the first shaft (2) is hollow, mounted on the second shaft (6), and is axially movable relative to the second shaft (6); - said plurality of engagement elements (10, 12, 14) are also translationally connected to said first shaft (2) and are axially movable together with said first shaft along said first longitudinal axis (X2) and relative to said second shaft (6); - the first actuator assembly (4) is configured to impart a translational movement along the first longitudinal axis (X2) to the first shaft (2), the translational movement being transmitted to the plurality of engagement elements (10, 12, 14) translationally connected to the first shaft (2); and The second actuator assembly (8) is configured to impart a rotational movement about the second longitudinal axis (X6) to the second shaft (6), said rotational movement being transmitted to the plurality of engagement elements (10, 12, 14) rotationally connected to the second shaft (6).

2. The system (1) according to claim 1, characterized in that The second shaft (6) is axially fixed.

3. The system (1) according to claim 1, characterized in that The first actuator assembly (4) includes a first rotary actuator (22), a first pinion (26) rotationally connected to an output shaft (24) of the first rotary actuator (22), and a rack (28) meshing with the first pinion (26), the rack (28) being translationally coupled to the first shaft (2).

4. The system (1) according to claim 3, characterized in that The first shaft (2) is freely rotatable relative to the rack (28).

5. The system (1) according to claim 1 or claim 4, characterized in that The first shaft (2) comprises a plurality of sections (18, 20) coupled together via the plurality of engagement elements and rotationally connected with the engagement elements.

6. The system (1) according to claim 3, characterized in that The second actuator assembly (8) includes a second rotary actuator (36), a transmission having an input element (40) coupled to an output shaft (38) of the second rotary actuator (36), and an output element (48) rotationally connected to the second shaft (6), the transmission being configured to transfer motion from the input element (40) to the output element (48).

7. The system (1) according to claim 6, characterized in that The second actuator assembly (8) includes a mounting flange (52) including a seat (54) for receiving the second rotary actuator (36), and a rotary bearing (57) for the first pinion (26) of the first rotary actuator (22).

8. The system (1) according to claim 6 or claim 7, characterized in that The input element (40) of the transmission is a second pinion connected to the output shaft (38) of the second rotary actuator (36), the second pinion meshing with a first toothing (44) of an idler gear wheel body (42) having a first diameter, the idler gear wheel body (42) having a second toothing (46) with a second diameter smaller than the first diameter, the second toothing meshing with a toothed sector rotatably connected to the second shaft (6) and defining the output element of the transmission.

9. The system (1) according to claim 3, characterized in that The first rotary actuator is a motor.

10. The system (1) according to claim 6, characterized in that The second rotary actuator is a motor.

11. A gearbox (100), comprising: - A system (1) according to any one of the preceding claims; - a main shaft (102) rotatable about a respective axis (Y102) and comprising a first plurality of gear wheels rotatably connected thereto; - a first secondary shaft (104) and a second secondary shaft (106), the first secondary shaft and the second secondary shaft being rotatable about respective axes parallel to each other and to the axis (Y102) of the main shaft, the first secondary shaft (104) and the second secondary shaft (106) comprising a second plurality of gear wheels and a third plurality of gear wheels, respectively, each of the gear wheels meshing with a corresponding gear wheel of the main shaft (102) to define a plurality of forward and reverse gears of the gearbox; as well as - the second plurality of gear wheels and the third plurality of gear wheels are idlingly mounted on the respective first and second layshafts and are selectively rotatably coupled to the respective first and second layshafts by means of respective engagement devices, each of the engagement devices being controlled by means of a respective fork engagement device (F1, F2, F3, F4), the fork engagement device having a control seat (CF1, CF2, CF3, CF4) configured to be selectively engaged by an engagement element (10, 12, 14) of the system (1); - wherein the first axis (2) and the second axis (6) of the system (1) are oriented transversely relative to the primary axis (102), the first secondary axis (104) and the second secondary axis (106).

12. The gearbox according to claim 11, characterized in that The gearbox further comprises a parking device (P), the parking device comprising a pawl (P1) which swings about an axis (YP1) parallel to the axis (Y106) of the second secondary shaft and elastically resists rotation, - the pawl (P1) is configured to engage with a sprocket (P2) which is rotationally connected to the second secondary shaft (106) and can be engaged in the sprocket (P2) via the sliding of a slider (P3), which is axially movable by being engaged by the plurality of engagement elements (10, 12, 14) and is rotationally driven via the second shaft (6) and the second actuator assembly.

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