Gearbox with a coupling device for connecting and / or disconnecting a gear to or from a shaft

Description

State of the art

[0001] The invention relates to a gearbox for an electric drive system with a coupling device for connecting and disconnecting a gear to or from a shaft.

[0002] Shift forks and associated mechanics are used in manual transmissions and dual-clutch transmissions.

[0003] For example, DE 10 2012 209 533 A1 discloses a switching actuator in a gearbox, comprising an electric motor, a spindle driven by the motor on which a threaded drive runs, and a switching fork mounted on a slide movable along a crossbeam. The threaded drive and a connection point of the switching fork are coupled to each other via a compression spring and a damper.

[0004] From CN 111 043 305 A, a coupling device for gear changes in a transmission is known, wherein the coupling device has an axially displaceable shift fork which is designed to engage with a shift sleeve, wherein a gear change is effected by displacing the shift fork, wherein the shift fork can be coupled to a shift sleeve in such a way that a shift sleeve coupled to it can be displaced along an axial direction by a drive of the shift fork, wherein an electromechanical actuator with a spindle is provided, wherein the spindle can be rotated about its longitudinal axis by means of the electromechanical actuator, wherein the shift fork is coupled to the spindle so that the shift fork can be displaced by a rotational movement of the spindle, wherein the shift fork is guided by means of a guide rod, wherein the guide rod has two sliding bushings.wherein the sliding bushings in a gearbox are fixable and wherein one end of the guide rod is guided in each sliding bushing, wherein the guide rod is guided by the sliding bushings such that the movement of the guide rod is limited to movement in the axial direction, wherein the shift fork is rigidly connected to the guide rod so that the shift fork is moved when the guide rod moves relative to the sliding bushings. The axially movable guide rod can be locked by means of a detent device.

[0005] From CN 110 985 665 A, a coupling device is known which comprises a switching fork that can be coupled to a switching sleeve and an electromechanical actuator with a spindle, wherein the spindle is rotatable about its longitudinal axis by means of the electromechanical actuator, wherein the switching fork is coupled to the spindle so that the switching fork can be displaced along an axial direction by a rotational movement of the spindle, and wherein the switching fork is guided by a guide rod. The switching fork is coupled to the guide rod, wherein the guide rod is axially displaceable at its ends in two sliding bearings. Furthermore, a detent device is provided which is designed to engage in notches on the guide rod when the guide rod is axially displaced.

[0006] From US patent 4,419,416 A, a transmission with a coupling device for engaging and / or disengaging a gear from a shaft is known, wherein the coupling device has a shift sleeve and a shift fork that are axially displaceable along the shaft, wherein the gear can be engaged and / or disengaged from the shaft by disengaging the shift sleeve, wherein the shift fork is coupled to the shift sleeve so that the shift sleeve can be disengaged along the shaft by driving the shift fork, wherein an electromechanical actuator with a spindle is provided, wherein the spindle is rotatable about its longitudinal axis by means of the electromechanical actuator, wherein the shift fork is coupled to the spindle so that the shift fork can be disengaged along the shaft by a rotational movement of the spindle, and wherein the shift fork is guided by means of a guide rod fixed in the transmission.The shift fork slides on the guide rod, with a pin engaging in a groove of a sliding shoe of the shift fork serving as a stop. Disclosure of the invention

[0007] The problem underlying the invention is solved by a transmission for an electric drive arrangement with a coupling device for connecting and / or disconnecting a gear to or from a shaft, having the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0008] A gearbox for an electric drive arrangement is proposed, comprising a coupling device for engaging and disengaging a gear from a shaft. The coupling device includes a shift sleeve and a shift fork that are axially displaceable along the shaft. The gear can be engaged and disengaged from the shaft by shifting the shift sleeve. The shift fork is coupled to the shift sleeve, allowing the shift sleeve to be moved along the shaft by driving the shift fork. An electromechanical actuator with a spindle is provided, the spindle being rotatable about its longitudinal axis by means of the electromechanical actuator (e.g., an electric motor). The shift fork is coupled to the spindle, allowing the shift fork to be moved along the shaft by a rotational movement of the spindle.The shift fork is guided by a guide rod, which has two sliding bushings. These sliding bushings are arranged in a gearbox housing, with one end of the guide rod guided in each bushing. The guide rod is guided by the sliding bushings in such a way that its movement is limited to a movement parallel to the shaft. The shift fork is rigidly connected to the guide rod, so that moving the shift fork also moves the guide rod relative to the sliding bushings. In contrast to the coupling devices mentioned above, the guide rod has two coaxially arranged stop sleeves, each positioned between the shift fork and one of the two sliding bushings, which limit the movement of the guide rod in both the coupling and discoupling directions.

[0009] The switching fork can be axially driven by the electromechanical actuator with spindle, with the guide rod guiding the switching fork (rotation of the switching fork around the spindle is prevented). The unwanted residual torque generated by the spindle drive is absorbed by the guide rod. Thus, the switching fork causes no or only negligible frictional forces on the switching sleeve.

[0010] According to the present invention, the shift fork is coupled to the guide rod in such a way that the shift fork is immobile relative to the guide rod. In other words, the shift fork is coupled to the guide rod in such a way that the shift fork and the guide rod can only be moved together (translationally).

[0011] Because the guide rod has two sliding bushings, with one end of the guide rod guided in each bushing, precise and low-friction guidance of the guide rod can be achieved. The shift fork is attached to the guide rod (when the guide rod moves relative to the sliding bushing(s), the shift fork moves with it). According to the invention, the guide rod has two stop sleeves that limit movement of the guide rod in the coupling and discoupling directions. The stop sleeves are arranged axially between a sliding bushing and the shift fork on the guide rod. Thus, several defined stops can be easily implemented in the design.

[0012] In this context, "coupling the gear to the shaft" means that the gear and the shaft are connected to each other in a rotationally fixed manner after coupling. Similarly, "discoupling the gear from the shaft" means that the gear and shaft can rotate relative to each other after decoupling.

[0013] The gear can be a pinion, especially if it (in a rotationally fixed state coupled to the shaft) drives another element or serves as an output element.

[0014] In this context, a displacement / movement / arrangement axially along the shaft or axial to the shaft is meant in relation to the longitudinal direction of the shaft. For example, a displacement axially along the shaft means a displacement along the longitudinal direction of the shaft.

[0015] The gear can have a clutch body with teeth. The shift sleeve can have internal teeth (internally toothed ring) or be coupled to internal teeth, with the internal teeth corresponding to the teeth on the clutch body. The shift sleeve and the clutch body can be components of a dog clutch or form a dog clutch. The dog clutch can have further elements, for example, a synchronizer ring and / or a guide sleeve.

[0016] According to further training, the spindle, guide rod, and / or shaft can be arranged parallel to each other. This allows for particularly precise guidance and accurate coupling and discoupling. Furthermore, this contributes to a structurally simple and stable drive.

[0017] According to a further development, the coupling device can be designed such that the coupling of the gear to the shaft is achieved by rotating the spindle in a first direction of rotation by means of the electromechanical actuator, thus shifting the shift fork and the shift sleeve in the coupling direction. This allows for simple coupling by rotating the spindle in the first direction of rotation.

[0018] According to a further development, the coupling device can be designed such that the gear is decoupled from the shaft by rotating the spindle in a second direction of rotation using the electromechanical actuator, thus shifting the shift fork and the shift sleeve in the decoupling direction. This allows for simple decoupling by rotating the spindle in the second direction of rotation (opposite to the first direction of rotation) or simple actuation by driving the actuator in the opposite direction. The first and second directions of rotation are opposite to each other (e.g., clockwise and counterclockwise, respectively). Likewise, the coupling and decoupling directions are opposite to each other.

[0019] According to further training, the shift fork can be coupled to the spindle via a spindle nut. This allows for a structurally simple and stable coupling.

[0020] According to a further development, the spindle can be guided at one end in a spindle bushing. This can promote precise spindle movement. This guide can be located at the free end of the spindle. According to another further development, the spindle can be guided at one end in a spindle roller bearing. This can also promote precise spindle movement. Furthermore, such support can be provided at the end of the spindle facing the electromechanical actuator. This allows forces acting on the spindle to be, at least in large part, transferred via the spindle roller bearing.

[0021] The transmission could be, for example, a transmission for an electric drive unit or an electric axle ("e-axle") of a vehicle or motor vehicle.

[0022] One possible embodiment of the invention is explained below with reference to the accompanying drawings. It shows: Figure 1 a perspective view of a coupling device which is part of a transmission according to the invention, and Figure 2 a sectional view from above of the coupling device acc. Fig. 1 .

[0023] Figure 1 Figure 1 shows a perspective view of a coupling device 10. The coupling device 10 serves to connect and / or disconnect a gear or pinion 21 to or from a shaft 14 (in Fig.1(The decoupled state is shown). For this purpose, the coupling device 10 has a switching sleeve 18 and a switching fork 20 that are axially displaceable along the shaft 14. The switching sleeve 18 and the switching fork 20 are coupled to each other in such a way that by displacing the switching fork 20, the switching sleeve 18 can be displaced along the shaft 14.

[0024] The coupling device 10, the gear or pinion 21, and the shaft 14 are presented here as part of a transmission 100 according to the invention. The shaft 14 is supported within a transmission housing of the transmission 100 by means of two rolling bearings, one of which is arranged in each of the sections 19 (not shown). The rolling bearings in the sections 19 can be inserted into the transmission housing, for example, by being pressed into corresponding bearing receptacles. A further gear 12 can be arranged on the shaft 14, which can, for example, be rotationally fixed to the shaft 14.

[0025] The shift fork 20 is rigidly connected to a guide rod 26. In other words, a displacement of the guide rod 26 causes a corresponding displacement of the shift fork 20, and vice versa.

[0026] The coupling device 10 has an electromechanical actuator 24 with a spindle 25. The electromechanical actuator 24 can drive the spindle 25 rotationally. In other words, the electromechanical actuator 24 can cause the spindle 25 to rotate about its longitudinal axis.

[0027] Figure 2 shows a sectional view from above of the coupling device 10 according to Fig. 1In this case, the shift fork 20 is coupled to the spindle 25 via a spindle nut 36. A rotation of the spindle 25 about its longitudinal axis causes a displacement of the spindle nut 36 and thus of the shift fork 20 along the spindle 25 (or along the longitudinal axis of the spindle 25).

[0028] Since the shift fork 20 is coupled to both the spindle 25 and the guide rod 26, the unwanted residual torque generated by the rotation of the spindle 25, which is transmitted to the shift fork 20, is absorbed by the guide rod 26. Thus, this torque is not transmitted from the shift fork 20 to the shift sleeve 18, where it could lead to friction losses and stresses.

[0029] The spindle 25, the guide rod 26 and the shaft 14 are arranged parallel to each other (see also Fig.1 ).

[0030] The spindle 25 is rotatably mounted at its end facing away from the electromechanical actuator 24 in a spindle sliding bushing 42. At its other end, facing the electromechanical actuator 24, the spindle 25 is rotatably mounted in a spindle roller bearing 44.

[0031] The guide rod 26 is received in two sliding bushings 38. Each sliding bushing 38 guides one end of the guide rod 26, allowing the guide rod 26 to be axially displaced. When the switching fork 20 is moved by means of the electromechanical actuator 24, the guide rod 26 and the switching sleeve 18 are also axially displaced along the shaft 14.

[0032] To couple the gear or pinion 21 to the shaft 14, the electromechanical actuator 24 sets the spindle 25 into rotation in a first direction of rotation 32. This causes the spindle nut 36, the shift fork 20, the guide rod 26 and the shift sleeve 18 to move in a coupling direction 34.

[0033] The guide rod 26 is guided through the sliding bushing 34, so that the movement of the guide rod 26 is limited to a movement parallel to the shaft 14.

[0034] Analogous to the rolling bearings in section 19, the sliding bushings 38, the spindle sliding bushing 42 and the spindle rolling bearing 44 can be arranged in the gearbox housing 101 of the gearbox 100. This is shown in Figure 2 indicated by hatched areas for the sliding bushings 38 and the spindle sliding bushing 42.

[0035] To decouple the gear or pinion 21 from the shaft 14, the electromechanical actuator 24 sets the spindle 25 into rotation in a second direction of rotation 28. This causes the spindle nut 36, the shift fork 20, the guide rod 26 and the shift sleeve 18 to move in a decoupling direction 30.

[0036] The guide rod 26 has two stop sleeves 40, 41. These are arranged coaxially on the guide rod 26. The stop sleeves 40, 41 are each arranged between the shift fork 20 and one of the two sliding bushings 38.

[0037] The stop sleeve 40 limits movement of the guide rod 26 in the decoupling direction 30 and the stop sleeve 41 limits movement of the guide rod 26 in the coupling direction 34.

Claims

1. Transmission (100) for an electrical drive arrangement with a coupling device (10), wherein the transmission (100) has a gear (21) and a shaft (14), wherein the coupling device (10) serves for coupling and decoupling the gear (21) to and from the shaft (14), wherein the coupling device (10) has a shift sleeve (18) which is displaceable axially along the shaft (14) and a shift fork (20), wherein displacement of the shift sleeve (18) allows the gear (21) to be coupled to the shaft (14) and decoupled from the shaft (14), wherein the shift fork (20) is coupled to the shift sleeve (18), such that driving of the shift fork (20) allows the shift sleeve (18) to be displaced along the shaft (14), wherein an electromechanical actuator (24) with a spindle (25) is provided, wherein the spindle (25) is rotatable about its longitudinal axis by means of the electromechanical actuator (24), wherein the shift fork (20) is coupled to the spindle (25), such that the shift fork (20) can be displaced along the shaft (14) by a rotational movement of the spindle (25), wherein the shift fork (20) is guided by means of a guide rod (26), wherein the guide rod (26) has two sliding bushings (38), wherein the sliding bushings (38) are arranged in a transmission housing (101) of the transmission (100) and an end of the guide rod (26) is guided in each sliding bushing (38), wherein the guide rod (26) is guided through the sliding bushings (38) in such a way that the movement of the guide rod is limited to a movement parallel to the shaft (14), wherein the shift fork (20) is firmly connected to the guide rod (26), such that the displacement of the shift fork (20) also causes the guide rod (26) to move relative to the sliding bushings, wherein the guide rod (26) has two stop sleeves (40, 41) arranged coaxially on the guide rod (26), which are each arranged between the shift fork (20) and one of the two sliding bushings (38) and which limit a movement of the guide rod (26) in the coupling direction (30) and the decoupling direction (24).

2. Transmission (100) according to Claim 1, characterized in that the spindle (25), the guide rod (26) and / or the shaft (14) are arranged parallel to one another.

3. Transmission (100) according to Claim 1 or 2, characterized in that the coupling device (10) is designed in such a way that the coupling of the gear (21) to the shaft (14) is achieved by a rotation of the spindle (25) by means of the electromechanical actuator (24) in a first direction of rotation (28) and thus a displacement of the shift fork (20) and the shift sleeve (18) in the coupling direction (30).

4. Transmission (100) according to any of the preceding claims, characterized in that the coupling device (10) is designed in such a way that the decoupling of the gear (21) from the shaft (14) is achieved by a rotation of the spindle (25) by means of the electromechanical actuator (24) in a second direction of rotation (32) and thus a displacement of the shift fork (20) and the shift sleeve (18) in the decoupling direction (34).

5. Transmission (100) according to any of the preceding claims, characterized in that the shift fork (20) is coupled to the spindle (25) by way of a spindle nut (36).

6. Transmission according to any of the preceding claims, characterized in that the spindle (25) is guided with one of its ends in a spindle sliding bushing (42).

7. Transmission (100) according to any of the preceding claims, characterized in that the spindle (25) is guided with one of its ends in a spindle rolling bearing (44).