One-way clutch for drive train of vehicle and drive train for vehicle

Abstract

The invention relates to a one-way clutch (1) for a drive train of a vehicle, comprising a clamping device (2) having a coupling sleeve (3) for transmitting a torque between a drive shaft (4) and a driven shaft (5); a coupling spring (6) for transporting the coupling sleeve (3) to a first torque-transmitting switching position between the driving shaft (4) and the driven shaft (5); and a switching device (7) provided for switching the clamping device (2) from a first switching position into a second switching position for separating the driving shaft (4) from the driven shaft (5), characterized in that the one-way clutch further comprises an overload protection device (8), an overload protection device (8) is provided for limiting a separating force, which separates the driving shaft (4) from the driven shaft (5), to a maximum value. The invention also relates to a drive train of a vehicle.

Description

Technical Field

[0001] This invention relates to a one-way clutch for a vehicle transmission system, the one-way clutch comprising a clamping device having a coupling sleeve for transmitting torque between a drive shaft and a driven shaft; a spring for conveying the coupling sleeve to a first switching position for transmitting torque between the drive shaft and the driven shaft; and a switching device for switching the clamping device from the first switching position to a second switching position for separating the drive shaft from the driven shaft. The invention also relates to a vehicle transmission system. Background Technology

[0002] One-way clutches are used in vehicles to disconnect the drive unit (especially the electric motor) from the vehicle wheels. This eliminates the need to drag the drive unit when it is not needed, for example, at all. This has a positive effect on improving energy efficiency. A one-way clutch has a mechanical device for disengagement that performs this function within the corresponding drivetrain. During this process, external factors such as uneven road surfaces can cause damage to the one-way clutch.

[0003] In this case, it is necessary to provide a one-way clutch for a vehicle's transmission system, and in particular, an improved one-way clutch for a vehicle's transmission system is needed. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to eliminate, or at least partially eliminate, the defects of the aforementioned one-way clutches used in vehicle transmission systems. In particular, the present invention aims to provide an improved one-way clutch for vehicle transmission systems.

[0005] For the aforementioned type of one-way clutch, the present invention solves the above-mentioned technical problem by providing an overload protection device, which is configured to limit the separation force that causes the driving shaft to separate from the driven shaft to within a maximum value. In particular, the above-mentioned technical problem is solved by a one-way clutch possessing the technical features of independent claim 1.

[0006] Furthermore, the aforementioned technical problem is also solved by a vehicle transmission system having the technical features of independent claim 9.

[0007] Herein, the technical features associated with the one-way clutch according to the invention are naturally also applicable to the transmission system according to the invention, and vice versa, so that each aspect of the invention can always be referred to in the disclosure of the invention.

[0008] According to a first aspect of the invention, a one-way clutch for a vehicle transmission system is provided, comprising a clamping device having a coupling sleeve for transmitting torque between a drive shaft and a driven shaft; a coupling spring for transporting the coupling sleeve to a first switching position for transmitting torque between the drive shaft and the driven shaft; and a switching device configured to switch the clamping device from the first switching position to a second switching position for separating the drive shaft from the driven shaft, characterized in that the one-way clutch further comprises an overload protection device configured to limit the separation force to a maximum value for separating the drive shaft from the driven shaft.

[0009] Here, the term "one-way clutch" specifically refers to a structural device configured to establish and release a torque transmission connection between a first shaft and a second shaft. The first shaft may preferably be a drive shaft. The second shaft may preferably be a driven shaft.

[0010] Here, the term "drivetrain" refers to a component configured to transmit power from the engine to the wheels. Furthermore, the drivetrain includes a drive shaft and a driven shaft. Here, the engine may preferably be an electric motor. A differential may preferably be located between the engine and the drive shaft. The driven shaft is preferably connected to the vehicle's wheels.

[0011] Here, the term "vehicle" specifically refers to a vehicle with an electric powertrain. This vehicle can be a battery electric vehicle (BEV) or a hybrid electric vehicle (HEV).

[0012] Here, the term "clamping device" specifically refers to a structural device configured to connect a drive shaft and a driven shaft to transmit torque.

[0013] Here, the term "coupling sleeve" specifically refers to a structural element configured to enable a mechanical connection for torque transmission between a drive shaft and a driven shaft.

[0014] Therefore, the coupling sleeve can have structural elements such as bolts, which enable form-fit and / or force-fit connections between the driving and driven shafts. The coupling sleeve can be a single piece or a multi-piece design.

[0015] Here, the term "combining spring" refers to a spring capable of applying a binding force. This spring may include a helical spring.

[0016] Here, the term "switching device" specifically refers to a device capable of actively switching between a first switching position and a second switching position.

[0017] Here, the term "first switching position" refers to a switching state in which the drive shaft and the driven shaft are connected so that the drive torque can be transmitted.

[0018] Here, the term "second switching position" refers to a switching state in which the driving shaft and the driven shaft are separated so that the drive torque cannot be transmitted.

[0019] Here, the term "transport (Verbringen)" refers to movement.

[0020] Here, the term "separation force" refers to a force required to move the coupling sleeve from the first switching position to the second switching position, thereby separating the driving shaft from the driven shaft.

[0021] Here, the term "overload protection device" refers to a structural component configured to limit the separation force that would separate the drive shaft from the driven shaft to a maximum value. The overload protection device can be a single unit or a multi-unit unit. A multi-unit unit is preferred.

[0022] This invention is based on the understanding that a switchable one-way clutch located at the half-shaft of an all-wheel-drive pure electric vehicle or hybrid vehicle can engage and disengage the drive of the entire shaft. For this purpose, the switchable one-way clutch can be installed between the differential and the half-shaft (i.e., the driven shaft). To achieve disengagement, a lifting magnet, utilizing a beveled profile to overcome the engagement spring, pushes a coupling sleeve (also called a wedge plate), thereby disconnecting the connection between the driving and driven shafts. The connection between the two shafts can be created by a radially positioned, oscillating pawl. During the switching of the disengagement direction, if torque is still being transmitted, the wedge plate is clamped by the pawl, resulting in a high lateral force acting on the lifting magnet. This situation can occur on uneven road surfaces, leading to shocks. For example, traversing a pothole at the moment of switching. In this case, the high lateral force may cause the switching element of the lifting magnet to break. To solve this problem, this invention proposes integrating an overload protection device into the one-way clutch, which limits the maximum force used to separate the driving and driven shafts. When an unintended impact occurs and causes the clamping device to jam, the connection can only be disengaged after the unintended jamming of the clamping device has spontaneously released. This can be, for example, shortly after the vehicle has driven over a pothole. In this way, the one-way clutch is protected from damage and the availability of the one-way clutch and its associated drivetrain is improved.

[0023] The preferred embodiments are defined in the dependent claims and are explained in detail below.

[0024] According to a preferred embodiment, the overload protection device may include an outer cover and a separation spring, wherein the separation spring is operatively connected to the coupling sleeve, and the overload protection device is configured to pre-tighten the outer cover against the separation spring when switching from a first switching position to a second switching position, so that the separation force acts on the coupling sleeve of the clamping device to realize the switching from the first switching position to the second switching position.

[0025] The release spring can be, for example, a helical spring. The action connection can be implemented by the contact between the release spring and the coupling sleeve. For this purpose, the coupling sleeve can be provided with steps, a point of action, and / or a stop. The release spring determines the maximum possible release force through its spring stiffness and a preset spring stroke. For this purpose, an overload protection device can, for example, move the housing a predetermined distance via an actuator. The actuator can be based on one of the following operating principles: pneumatic, electromagnetic, or hydraulic. For example, the housing can have a point of action for the actuator to operate.

[0026] This method allows for reliable setting of the maximum separation force. It protects the one-way clutch from damage and improves its availability.

[0027] According to a preferred embodiment, the maximum value of the separating force of the separating spring can be greater than the maximum value of the engaging force of the engaging spring of the switching device.

[0028] The maximum separation force of the release spring can be set by its spring stiffness and spring travel. Similarly, the maximum engagement force of the engagement spring can be set by its spring stiffness and spring travel. For example, with the same spring travel, a larger spring stiffness can be selected for the release spring. For example, with the same spring stiffness, a larger spring travel can be structurally designed for the release spring. Other combinations are also feasible, as long as the product of the release spring stiffness and spring travel is greater than the applied engagement force.

[0029] This method ensures that the separation force exceeds the applied engagement force acting in the opposite direction, thereby disengaging the drive shaft from the driven shaft at the second switching position (provided no excessive torque is applied). This method preferably achieves overload protection at a low cost.

[0030] According to a preferred embodiment, the outer cover may have a beveled profile for pre-tensioning the release spring.

[0031] Here, the term "sloping profile" specifically refers to an inclined surface. Preferably, the switching device may have a switching element that can pre-tighten the outer cover during translational movement when in contact with the inclined surface. The sloping profile may be provided on the end face of the outer cover. The sloping profile may be provided at least around a portion of the circumference of the outer cover. Preferably, the switching element is recessed into the sloping profile so that the outer cover is translated a specific distance.

[0032] This method allows for efficient, repeatable, precise, and reliable pretensioning of the release spring. Furthermore, this solution offers the advantage of low manufacturing costs.

[0033] According to a preferred embodiment, the coupling sleeve may have a stop for supporting the release spring.

[0034] The release spring can be supported by a stop. The release spring can transmit the separation force to the coupling sleeve via the stop. The stop can be provided at least along a portion of the circumference of the coupling sleeve. The stop can include a flange or a protrusion. The coupling sleeve and the stop can be implemented as a single piece, a monolithic piece, or multiple pieces. The stop and the coupling sleeve are preferably implemented as multiple pieces.

[0035] This method allows for the simple application of separation force to the coupling sleeve while simultaneously limiting that force. This has a positive effect on manufacturing costs.

[0036] According to a preferred embodiment, the switching device may have a lifting magnet with a switching element for switching the clamping device, wherein the switching element is configured to pre-tighten the outer cover against the separation spring when switching from a first switching position to a second switching position.

[0037] Here, the term "switching element" refers to a structural component capable of moving the outer casing. The switching element may, for example, comprise a cuboid or a cylinder. Preferably, the switching element can be translated by a lifting magnet. Preferably, the switching element is recessed into the inclined profile of the outer casing and moves the outer casing longitudinally a predetermined distance, thereby pre-tensioning the separation spring.

[0038] In this way, overload protection devices can be implemented efficiently.

[0039] According to a preferred embodiment, the switching element may include a rolling bearing configured to preload the outer casing against the release spring when switching from a first switching position to a second switching position.

[0040] The rolling bearing is preferably located at the top of the switching element. The rolling bearing advantageously avoids unwanted torque caused by the rotational movement of the housing.

[0041] According to a preferred embodiment, the clamping device may include at least one clamping element for connecting the drive shaft and the driven shaft, wherein the coupling sleeve is capable of clamping at least one clamping element in a first switching position, thereby transmitting torque.

[0042] The clamping element can be flexibly mounted on the drive shaft and / or driven shaft. To improve motion flexibility, the clamping element and / or coupling sleeve may have a chamfered or beveled surface at their common contact point.

[0043] In this way, the clamping device can be implemented in a simple manner.

[0044] Another aspect of the invention relates to a vehicle drivetrain that includes the one-way clutch described in detail above.

[0045] According to a preferred embodiment, the vehicle may be a pure electric vehicle or a hybrid vehicle. Attached Figure Description

[0046] The present invention will now be described in detail with reference to the accompanying drawings. The drawings include:

[0047] Figure 1 A longitudinal sectional view of a first embodiment of a one-way clutch designed according to the present invention at a first switching position;

[0048] Figure 2 : A schematic diagram of the first embodiment of the outer cover with a beveled profile designed according to the present invention;

[0049] Figure 3 A longitudinal sectional view of a first embodiment of a one-way clutch designed according to the present invention at a first switching position;

[0050] Figure 4 A transverse sectional view of a first embodiment of a one-way clutch designed according to the present invention at a first switching position;

[0051] Figure 5 A longitudinal sectional view of a first embodiment of a one-way clutch designed according to the present invention at a second switching position;

[0052] Figure 6 : A transverse sectional view of a first embodiment of a one-way clutch designed according to the present invention in the second switching position.

[0053] The same elements correspond to the same reference numerals. The technical features of the various embodiments can be substituted, supplemented or replaced by each other. Detailed Implementation

[0054] Figure 1A one-way clutch 1 for a drivetrain of a vehicle (not shown) is illustrated. The vehicle here is a pure electric vehicle with four independently driven wheels. An electric motor (not shown) is connected to a drive shaft 4 via a differential (not shown). The drive shaft 4 is connected to a driven shaft 5 via a clamping device 2. The driven shaft 5 is connected to a wheel (not shown). A coupling sleeve 3 is arranged around the driven shaft 5 to connect the drive shaft 4 and the driven shaft 5. A spring 6 presses the coupling sleeve 3 towards a first switching position. In this first switching position, torque can be transmitted. For this purpose, the front region of the coupling sleeve 3 clamps a swingable clamping element 16 between the drive shaft 4 and the driven shaft 5. The one-way clutch 1 also has a switching device 7, which includes a lifting magnet 13, a switching element 14, and a rolling bearing 15 disposed at the switching element 14. The switching device 7 is here configured to switch between a first switching position and a second switching position. The first switching position is shown here, in which the drive shaft 4 and the driven shaft 5 are connected. The switching element 14 is retracted. The one-way clutch 1 also has an overload protection device 8. The overload protection device 8 includes an outer cover 9, which surrounds the coupling sleeve 3. A release spring 10 abuts against the outer cover 9. The release spring 10 is supported at a stop 12 of the coupling sleeve 3. The stop 12 is part of the coupling sleeve 3. By means of the lifting magnet 13, the rolling bearing 15 can push the outer cover 9 to the right, thereby causing the release spring 10 to contract and provide maximum separation force. As long as there is no unwanted torque in the clamping device 2, the separation force is sufficient to overcome the engagement force of the engagement spring 6 through the stop 12 and guide the coupling sleeve 3 to a second switching position, thereby decoupling the drive shaft 4 from the driven shaft 5.

[0055] Figure 2 An outer casing 9 with a beveled profile 11 is shown. When the lifting magnet 13 is activated, it presses the rolling bearing 15 into the annular beveled profile 11. Rotation of the outer casing 9 causes it to move accordingly and preload the release spring 10.

[0056] Figure 3 The diagram shows a position of the inclined profile 11 of the outer casing 9, where the rolling bearing 15 is not yet submerged in the inclined profile 11. Only as the inclined profile 11 continues to rotate with the outer casing 9 can the rolling bearing 15 extend into and push the outer casing 9.

[0057] Figure 4 Clamping element 16 is shown, which is clamped to the drive shaft 4 via coupling sleeve 3. Clamping element 16 is here elastically mounted on the driven shaft 5. The first switching position is shown here.

[0058] Figure 5The second switching position is shown, in which the rolling bearing 15 has preloaded the release spring 10 to its maximum separation force. However, the coupling sleeve 3 remains engaged with the clamping device 2. At this point, the vehicle happens to traverse a pothole. The resulting impact force undesirably generates torque between the drive shaft 4 and the driven shaft 5. This results in a clamping force exceeding the maximum separation force. Therefore, the overload protection device 8 intervenes, and the coupling sleeve 3 does not move to the desired switching position.

[0059] and Figure 5 compared to, Figure 6 The state after the unwanted torque disappears is shown (e.g., because the vehicle has driven over a pothole). At this point, the rolling bearing 15 is still in the second switching position. The release spring 10 is now able to move the coupling sleeve 3 to the right, thereby disengaging the clamping device 2 from the connection between the drive shaft 4 and the driven shaft 5.

[0060] List of reference numerals

[0061] 1. One-way clutch

[0062] 2. Clamping device

[0063] 3. Coupling sleeve

[0064] 4. Drive shaft

[0065] 5 Driven Shaft

[0066] 6. Combined with springs

[0067] 7. Switching device

[0068] 8. Overload protection device

[0069] 9. Outer Cover

[0070] 10. Separation Spring

[0071] 11. Inclined plane profile

[0072] 12 stops

[0073] 13 Lifting Magnet

[0074] 14 Switching elements

[0075] 15 Rolling bearings

[0076] 16 Clamping elements

[0077] 17. Casing

Claims

1. A one-way clutch (1) for a vehicle transmission system, comprising: A clamping device (2) is provided, the clamping device (2) having a coupling sleeve (3) for transmitting torque between the driving shaft (4) and the driven shaft (5). The coupling spring (6) is used to transport the coupling sleeve (3) to a first switching position for transmitting torque between the drive shaft (4) and the driven shaft (5). A switching device (7) is configured to switch the clamping device (2) from the first switching position to the second switching position, so as to separate the driving shaft (4) from the driven shaft (5). Its features are, The one-way clutch (1) also includes an overload protection device (8) configured to limit the separation force that separates the drive shaft (4) from the driven shaft (5) to a maximum value.

2. The one-way clutch according to claim 1, characterized in that, The overload protection device (8) includes an outer cover (9) and a release spring (10). The separation spring (10) is operatively connected to the coupling sleeve (3). The overload protection device (8) is configured to pre-tighten the outer cover (9) against the separation spring (10) when switching from the first switching position to the second switching position, so that the separation force acts on the coupling sleeve (3) of the clamping device (2) to switch from the first switching position to the second switching position.

3. The one-way clutch according to claim 2, characterized in that, The maximum value of the separation force of the separation spring (10) is greater than the maximum value of the connection force of the connection spring (6) of the switching device (7), wherein the spring stiffness of the separation spring is greater than the spring stiffness of the connection spring.

4. The one-way clutch according to claim 2, characterized in that, The outer cover (9) has a beveled profile (11) for pre-tightening the release spring (10).

5. The one-way clutch according to any one of claims 2 to 4, characterized in that, The coupling sleeve (3) has a stop (12) for supporting the separation spring (10).

6. The one-way clutch according to any one of claims 2 to 5, characterized in that, The switching device (7) includes a lifting magnet (13) with a switching element (14) for switching the clamping device (2), wherein the switching element (14) is configured to pre-tighten the outer cover (9) against the separation spring (10) when switching from the first switching position to the second switching position.

7. The one-way clutch according to claim 6, characterized in that, The switching element (14) includes a rolling bearing (15) configured to preload the outer cover (9) against the separation spring (10) when switching from the first switching position to the second switching position.

8. The one-way clutch according to any one of the preceding claims, characterized in that, The clamping device (2) includes at least one clamping element (16) for connecting the drive shaft (4) and the driven shaft (5), wherein, in the first switching position, the coupling sleeve (3) clamps the at least one clamping element (16) so that torque can be transmitted.

9. A transmission system for a vehicle, comprising a one-way clutch (1) according to any one of claims 1 to 8.

10. The transmission system according to claim 9, characterized in that, The vehicle is a pure electric vehicle or a hybrid vehicle.

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