Ventilated mechanical power transmission device and pedal-propelled vehicle having such a power transmission device

Abstract

A ventilated mechanical power transmission device (1) and a pedal-propelled vehicle having the power transmission device, wherein the power transmission device includes a housing (10), a first seal (51), and a first shaft (41) extending through the first seal (51) and through the wall of the housing (10), wherein the first shaft (41) is configured to rotate relative to the housing (10), and at any three-dimensional rotational position of the mechanical power transmission device (1), the vent channel (30) is configured to release a pressure difference between the interior and exterior of the housing (10).

Description

Technical Field

[0001] The present invention relates to a vent system for a mechanical power transmission device, and more particularly to a mechanical power transmission device that is configured to rotate in different directions during use, such as a bicycle transmission for example. Background Art

[0002] As personal mobility devices become more common and in greater demand, new types or improvements of well-known transportation devices continue to appear on the market. Such devices may be, for example, human-powered, such as pedal-propelled bicycles, scooters, etc., or they may be powered by a similar device, such as an electric bicycle or an electric scooter.

[0003] Traditionally, mechanical wear of components of personal mobility tools has been accepted because maintenance and component costs have been relatively low due to the simplicity of the mechanical design.

[0004] However, as complexity increases, so do the costs associated with repairing damaged or worn components.

[0005] Some wear and tear may be related to the operating environment and may vary by geographic location. Another factor is that the actual use of traffic working devices can vary greatly and result in large individual differences in wear and tear between device types operating in the same environment.

[0006] The extent of wear may also be related to the mechanical structure itself, such as the design or materials chosen for a particular implementation.

[0007] In common real-world situations, the above-mentioned different types of wear-related parameters are combined into total wear.

[0008] Furthermore, as devices become increasingly complex, the functional components of the drivetrain tend to be embedded within a container or housing. This is for several reasons. First, as the devices themselves become increasingly complex, it becomes impossible to assemble all parts on a single assembly line. Second, due to their complexity and the need for lightweight construction, internal components can be fragile, so the housing serves as a means of protecting them. Third, the container or housing can be viewed as having a functional interface that can be reused for several applications or devices. Such groups of functional components can be considered separate subsystems. Today, subsystems are often provided by OEM suppliers.

[0009] Examples of such subsystems may be, for example, a gearbox, an electric motor, a braking system or other functional groups or combinations of such functional groups.

[0010] When a subsystem has a mechanical interface such as a rotating or moving shaft, a seal is placed between the shaft and the housing to prevent dust, liquids, and other substances from entering the housing. Similarly, the seal prevents any fluids such as lubricants in the housing from escaping.

[0011] However, after a period of actual operation, by monitoring the condition of a traffic working device having a gear box, a motor housing, etc., it can be easily observed that internal components such as bearings are often worn out before their expected lifespan.

[0012] In order to successfully transition from polluting transportation to green mobility, it is important that personal transportation devices using clean energy, such as human- or electric-assisted bicycles, can operate with longer service intervals and with less wear and tear on internal components. Summary of the Invention

[0013] An object of the present invention is to overcome the problems of the prior art and to disclose a system and method for increasing the life of a transmission system of a traffic working device.

[0014] The present invention solves the problem often encountered in mechanical power transmission devices that are affected by varying operating conditions such as humidity, temperature, etc.

[0015] Because devices like bicycle gears or electric motors are designed to rotate, they require extensive sealing to prevent the introduction of dirt and dust into the housing and transmission mechanism. This applies to both dry and liquid lubricants. If liquid lubricants are used, sealing is a further incentive to prevent oil leaks.

[0016] The seals used in bicycle drives are optimized for low friction, resulting in lower contact pressures on the dynamic sealing surfaces compared to conventional seals in the industrial and automotive sectors. This can lead to small leaks when the pressure difference between the inside and outside of the housing changes, for example due to atmospheric or temperature variations.

[0017] As a result, seals may not always function as expected. Seals can fail when the pressure differential between the outside and inside of the housing gradually builds up, and pressure builds up through the bearing adjacent to the seal. This has several consequences. If a dry lubricant or grease is used, the lubricant begins to dry out or clump. If a liquid lubricant is used, the seal may begin to leak after a while. Furthermore, each time pressure builds up through the seal, the sealing ability weakens as particles begin to interfere with the seal. More and more particles, contaminants, and moisture will enter the housing, causing premature wear of internal components.

[0018] Due to such accidental leakage, the efficiency of the device will be reduced.

[0019] The following invention addresses these problems of rotatable mechanical power transmission, which requires a different solution than non-rotating power transmission. The solution utilizes modifications to components already available as part of such transmissions and is applicable to rotatable power transmissions utilizing both liquid and dry lubrication.

[0020] The invention that solves the above-mentioned problems is a ventilated mechanical power transmission device and a pedal-propelled vehicle according to the present invention. The ventilated mechanical power transmission device includes: a housing; a first seal; a first shaft extending through the first seal and through a wall of the housing, wherein the first shaft is configured to rotate relative to the housing; and a vent passage configured to relieve a pressure difference between the interior and exterior of the housing at any three-dimensional rotational position of the mechanical power transmission device, wherein the housing is configured to be partially filled with a liquid lubricant, wherein the vent passage has a first end and a second end, wherein the first end is outside the housing and the second end is inside the housing, and wherein the second end is configured to remain above the liquid lubricant at any three-dimensional rotational position of the mechanical power transmission device; and wherein the housing includes a first chamber and a second chamber, and wherein the vent passage includes a second fluid connector, the second fluid connector including the second end and an upper end opposite the second end, wherein the second end is disposed in the first chamber and the upper end is disposed in the second chamber.

[0021] The effect of the invention is that the life of the transmission system of a traffic working device can be improved, at least under certain conditions, and the maintenance intervals can be increased.

[0022] An effect of the invention is that the life of the drive trains of smaller traffic working devices that are arranged to rotate in different directions as part of normal operation can be improved so that their drive train rotation can be improved, for example as part of left or right turns, forward reverse, or even reverse. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A cross-sectional view of a mechanical power transmission device (1) for a wheel hub according to an embodiment of the present invention is shown.

[0024] Figure 2 Shows a tilt to one side Figure 1 A mechanical power transmission device (1).

[0025] Figure 3 Shown in more detail Figure 1 and Figure 2 The first shaft (41) in the embodiment.

[0026] Figure 4a 、 Figure 4b and Figure 4c Another embodiment of the invention is shown, wherein the housing includes an electric motor (200).

[0027] Figure 5 A ventilated mechanical power transmission device (1) in an embodiment of the present invention is schematically shown.

[0028] Figure 6 Embodiments of the present invention are schematically shown. DETAILED DESCRIPTION

[0029] In the following description, multiple examples and embodiments of the present invention are set forth to provide a more thorough understanding of the present invention for those skilled in the art. The specific details described in the context of multiple embodiments and with reference to the accompanying drawings are not intended to be construed as limiting. Instead, the scope of the present invention is defined in the appended claims.

[0030] The specific embodiments shown in the drawings will be described below.

[0031] Figure 1 A cross-sectional view of a mechanical power transmission device (1) for a wheel hub according to an embodiment of the invention is shown. Inside the housing (10) there is an internal gear (20), which can be of a planetary type, for example. A hollow second shaft (42), in this case a main shaft (42), extends through the housing. Inside the main shaft is a first shaft (41), which in this case is a gearshift shaft, which is also hollow to allow a through bolt (45) to pass through the wheel hub to secure the main shaft (42) to a frame, such as a bicycle frame.

[0032] The wheels are driven by a sprocket or pulley (61) connected to the crank of the bicycle. The sun gear (20a) of the internal gear (20) is fixed around the main shaft (42) and the ring gear (20c) driven by the planetary gear is fixed to the housing (10). The gears can be shifted by rotating the shift shaft (41) having radial shift cams (44a, 44b). The shift cams radially push the shift elements through the first and second holes (33, 34) in the main shaft (42) to change the transmission ratio.

[0033] The specific operation of the gears is not essential to the present invention.

[0034] On each side, between the shift shaft and the main shaft, there are second and first seals (52, 51) on the first and second holes (33, 34), respectively. The area between the seals can be considered to belong to the interior of the housing, isolated from external dust, contamination, etc. Similarly, any fluid such as lubricant between the seals is prevented from leaking out of the housing by the seals.

[0035] To allow the shift shaft (41) to rotate, its inner diameter is larger than the outer diameter of the through bolt (45). This provides space for a breather passage (30) between a first end (31) at one end of the main shaft (42) and a second end (32) which is a breather hole through the wall of the first shaft (42). Dust caps (37) or similar elements may be present at both ends to protect the gears from dirt and dust, but this does not prevent pressure adjustment through the breather passage.

[0036] Furthermore, the ventilation channel (30) is in fluid communication with the rest of the interior of the housing (10), i.e., the space outside the second shaft (42), via first and second holes (33, 34). These holes are used to accommodate a shift element arranged between the shift cam of the shift shaft and the clutch located in the internal gear (20), but in this case also serve to allow fluid to pass through.

[0037] In this case, it can be said that the first and second holes (33, 34) have multiple functions. First, they allow the clutch in the internal gear (20) to be operated by the shift shaft. Second, they allow lubrication of the shift cam. Third, they are part of the ventilation channel between the inside and outside of the housing to allow constant pressure regulation to reduce wear on internal components.

[0038] In this embodiment, it is assumed that the housing contains liquid lubricant and the liquid level (L) has been indicated. At this position, the mechanical power transmission device can be vented as described above.

[0039] Figure 2 Shows a tilt to one side Figure 1 A mechanical power transmission device (1) of the present invention is provided. The liquid level (L) changes relative to the housing, and the main shaft may be covered with liquid. The liquid may enter the first or second hole (33, 34) interconnecting the annular space between the first and second shafts (41, 42) with the gear chamber of the housing (10). However, as long as the second end (32) of the vent channel (30) is arranged substantially in the middle of the housing, the liquid will generally not be able to escape from the mechanical power transmission device.

[0040] It should also be mentioned that in this case the liquid that has reached the annular space will be rotated back to the Figure 1 When in the middle position, the liquid is discharged into the main housing through the first hole or the second hole (33, 34).

[0041] Furthermore, since the first and second seals (51, 52) are arranged adjacent to the outside of the second and first holes (34, 33), respectively, liquid will not accumulate in the ends of the annular space between the first and second shafts (41, 42).

[0042] Figure 3Shown in more detail Figure 1 and Figure 2 It can be noted that the guide cam (43) is configured to radially guide the first shaft (41) inside the second shaft (42) and has one or more radial recesses to allow air to flow between the main hole at the second end (32) and the first and second shift cams (44a, 44b), and the first and second shift cams coincide with the positions of the first and second holes (33, 34) of the second shaft (42) in the longitudinal direction.

[0043] Figure 4a 、 Figure 4b and Figure 4c Another embodiment of the invention is shown, in which the housing includes an electric motor (200). This can be, for example, a crank motor for an electric bicycle. The stitching shows how the interior of the housing is ventilated via a first shaft (41).

[0044] The first shaft (41) is here a hollow crankshaft. The first shaft (41) can be driven by an electric motor (200), for example by a belt passing through pulleys at each end, either directly or via an internal fixed or shiftable gear system (20). In an embodiment, the gears can instead be arranged coaxially with the electric motor.

[0045] In this embodiment, the housing contains a liquid lubricant, the level (L) of which is as shown.

[0046] Figure 4a The main components of the housing are shown schematically from the side when the bicycle is in the normal upright position.

[0047] Figure 4b and Figure 4c The diagram is schematically shown from above. Figure 4a The same components are shown in Figure 1. Pedal arms on each side of the mechanical power transmission are shown. The first shaft (41) is supported by bearings (71, 72) arranged in the wall of the housing, and first and second seals (51, 52) seal the housing from the external environment and vice versa.

[0048] exist Figure 4b In the mechanical power transmission device relative to Figure 4a Rotate backwards, Figure 4c The housing is further rotated or tilted sideways. The rotation and tilting cause the liquid level (L) to change relative to the internal components of the mechanical power transmission device. As long as the second end (32) of the vent channel (30) is arranged substantially in the middle of the housing, liquid will generally not be able to escape the mechanical power transmission device through the vent channel, even if the housing is turned upside down.

[0049] Figure 5 An embodiment of the present invention is schematically shown having a ventilated mechanical power transmission device (1). It includes a housing (10), a first seal (51), a first shaft (41) extending through the first seal (51) and the wall of the housing (10), wherein the first shaft (41) is configured to rotate relative to the housing (10). The first shaft is supported by rotary bearings (71, 72) in the wall of the housing (10), and in this case, only one end of the first shaft extends from the housing. The extended end is sealed by the first seal (51). A vent channel (30) configured to release the pressure difference between the inside and outside of the housing (10) in any three-dimensional rotational position of the mechanical power transmission device (1) extends through the hollow first shaft (41). The vent channel (30) has a first end (31) and a second end (32), wherein the first end (31) is outside the housing and the second end (32) is inside the housing.

[0050] The rectangle inside the housing (10) may represent any mechanical transmission component in contact with the first shaft (41). The first shaft may be rotationally fixed or integrated with gears, pulleys, clutches, etc., and may also be in mechanical contact with other components such as a mechanical reducer, an electric motor, etc.

[0051] In an embodiment, both ends of the first shaft (41) may extend through the housing wall. In this case, additional seals may be used.

[0052] In a related embodiment, the first shaft (41) is split within the housing (10) to allow the left and right portions to rotate independently or at different speeds, such as in a differential, for example.

[0053] Figure 6 An embodiment of a ventilated mechanical power transmission device for use in a drive system for a pedal-propelled vehicle such as a bicycle is schematically shown, the ventilated mechanical power transmission device including an electric motor (200) and a multi-speed gear (20). The ventilated mechanical power transmission device includes a housing (10) divided into a first chamber and a second chamber (11, 12), wherein the first chamber (11) is configured to be partially filled with lubricant and the second chamber (12) is configured to be dry. The ventilated mechanical power transmission device also includes a first shaft (41) configured to rotate relative to the housing and extending through the first chamber and supported by first and second rotary bearings (71, 72) in opposite walls of the first chamber (11). First and second seals (51, 52) on the outside of each of the first and second bearings prevent lubricant from escaping from the first chamber. In this case, the first shaft is a crankshaft having a pedal arm.

[0054] The multi-speed gear has a variable transmission ratio between an input shaft (21) and an output shaft (22). Additional seals and bearings may be provided between the shafts and the one-way clutch as appropriate. A main sprocket (23) is arranged on the output shaft and is configured to drive the wheels of the vehicle via a chain (24).

[0055] The motor (200) is arranged in the dry second chamber (12), but the motor shaft (241) extends into the first chamber and is supported by a motor shaft rotation bearing (271) in the intermediate wall. In addition, a motor shaft seal (251) is arranged near the bearing.

[0056] A motor transmission device (201) comprising a sprocket on a motor shaft, a sprocket coaxially arranged on a first shaft and a connecting chain allows the input shaft of a multi-speed gear to be driven by the motor.

[0057] The input shaft (21) can also be driven by the first shaft (41), ie the crankshaft. One-way clutches can be used between the motor drive and the input shaft and between the crankshaft and the input shaft to prevent the motor drive from driving the crankshaft and the crankshaft from driving the motor.

[0058] As previously described, the vent passage (30) has a first end (31) and a second end (32), wherein the first end (31) is outside the housing and the second end (32) is inside the housing, and wherein the second end is configured to remain above the liquid lubricant in the first chamber at any three-dimensional rotational position of the mechanical power transmission device.

[0059] In this embodiment, the second chamber forms part of the vent channel, i.e. the vent channel comprises a first fluid connection (301) between the first end (31) and the second chamber and a second fluid connection (302) between the second chamber and the second end (32). Furthermore, the vent channel comprises the second chamber itself.

[0060] In the normal driving position of the vehicle, the second end is lower than the first end, and the first chamber is lower than the second chamber. Therefore, in this position, the second fluid connection (302) has an upper end (312) that is opposite the second end (32) and terminates in the second chamber (12). The first connection (301) has a lower end (311) that is opposite the first end (31) and also terminates in the second chamber (12). In the normal driving position, as shown by the vertical distance h in the figure, the lower end (311) is lower than the upper end (312).

[0061] As previously mentioned, the vent channel allows the pressure to be adjusted between the interior of the power transmission device and the surrounding environment to avoid leakage through the seal. This results in a shortened service life and / or increased maintenance requirements. When the temperature gradient is small, that is, when the temperature changes slowly within the housing (10), the temperature difference between the components remains small and the pressure difference remains small. The motor will gradually heat up and the heat will be distributed through the housing wall or other components in the system. When the temperature changes, the pressure in the first chamber and the second chamber will change, and the power transmission device will be ventilated through the first connector and the second connector. For example, any pressure difference between the first chamber and the second chamber (11, 12) will be adjusted by the second fluid connector (302), and any pressure difference between the outside and the second chamber will be adjusted (aligned) by the first fluid connector (301).

[0062] If the temperature drops immediately, such as when traveling through a river, the pressure will drop. If the first end 31 is below the water level when this pressure drop occurs, some water from the outside may be drawn into the second chamber, as indicated by the wavy line. However, because the first and second connecting members are separated and the upper end remains above the water level, water infiltration will cease when the pressure difference is adjusted, preventing water from entering the first chamber.

[0063] The next time the vehicle is operated, after water is introduced into the second chamber, or after a rest period, the second chamber will heat up due to the heat from the motor. When this happens, the pressure in both chambers increases, and water will be blown from the lower end in the water to the first end outside the power transmission device through the first fluid connection.

[0064] To reduce direct exposure to external fluids such as rain, splashing etc., the first end is arranged within the frame of the vehicle. This may be implemented as a tube extending upwardly through a frame element, such as within the seat tube of a bicycle frame for example. Figure 6 The first end (31) is shown to be a tube extending outside the housing (10).

[0065] Further embodiments of the present invention are given below. These are numbered. In addition, dependent embodiments defined with respect to the numbered embodiments are described. Unless otherwise indicated, any embodiment that can be combined with one or more numbered embodiments can also be directly combined with any dependent embodiment of the mentioned numbered embodiment.

[0066] In a first embodiment of the device, the present invention is a ventilated mechanical power transmission device (1) comprising:

[0067] - housing (10);

[0068] - a first sealing member (51);

[0069] a first shaft (41) extending through the first seal (51) and the wall of the housing (10), wherein the first shaft (41) is configured to rotate relative to the housing (10),

[0070] A vent channel (30) configured to relieve the pressure difference between the inside and the outside of the housing (10) in any three-dimensional rotational position of the mechanical power transmission device (1).

[0071] In a second embodiment of the device that can be combined with the device of the first embodiment, in the present invention, the housing (10) is constructed to be partially filled with a liquid lubricant, wherein the ventilation channel (30) has a first end (31) and a second end (32), wherein the first end (31) is outside the housing and the second end (32) is inside the housing, and wherein the second end is constructed to remain above the liquid lubricant at any three-dimensional rotational position of the mechanical power transmission device.

[0072] In a device of a third embodiment which can be combined with the device of the first embodiment or the device of the second embodiment, the first shaft (41) is hollow, and wherein at least some portion of the first shaft (41) constitutes at least a portion of the ventilation channel.

[0073] In a first subsidiary embodiment, the second end (32) is a vent hole in the wall of the first shaft (41).

[0074] In a second subsidiary embodiment which may be combined with the first subsidiary embodiment, the vent hole (ie the second end) is arranged at an intermediate position between the inner walls of the housing.

[0075] In a device of a fourth embodiment which can be combined with any one of the first to third embodiments, it includes a hollow second shaft (42) which is coaxially arranged outside the first shaft (41) and is configured to rotate relative to the first shaft (41), wherein the second shaft (42) includes a first hole (33), wherein a fluid channel is maintained between the second end (32) and the first hole regardless of the rotational position between the first and second shafts (41, 42).

[0076] In a first related embodiment, the outer diameter of the first shaft (41) in the cross section of the vent hole (32) is smaller than the inner diameter (33) of the second shaft (42) in the cross section of the first hole.

[0077] In a second related embodiment that can be combined with the first related embodiment, the first shaft (41) includes a guide cam (43) that is configured to radially guide the first shaft (41) relative to an inner portion of the second shaft (42), wherein the guide cam (43) is arranged between the main hole and the first hole and is further configured to allow fluid to flow between the main hole and the first hole.

[0078] In the device of the fifth embodiment which can be combined with the device of the fourth embodiment and any of its dependent embodiments, the second shaft (42) includes a second hole (34), wherein the first hole and the second hole (33, 34) are arranged on opposite sides of the second end (32) (i.e. the vent hole of the first shaft (41)).

[0079] In a related embodiment, the ventilated mechanical power transmission device includes a second seal (52), wherein the first and second seals (51, 52) are arranged between the first and second shafts (41, 42) outside the second hole and the first hole (34, 33), respectively.

[0080] The vented mechanical power transmission device (1) may include a protective element (37) such as a dust cap, which is configured to protect the vent channel (30) from introducing external liquid or particles into the vent channel.

[0081] In a device of a sixth embodiment that can be combined with any one of the devices of the second embodiment to the fifth embodiment described above, the housing (10) includes a first chamber and a second chamber (11, 12), wherein the ventilation channel (30) includes a fluid connector (302), which includes a second end (32) and an upper end (312) opposite to the second end, wherein the second end is arranged in the first chamber (11) and the upper end is arranged in the second chamber (12).

[0082] In a first subsidiary embodiment, the vent channel comprises a first fluid connection (301) comprising a first end (31).

[0083] In a second dependent embodiment which can be combined with the first dependent embodiment, the first fluid connection comprises a lower end (311) opposite the first end, wherein the first end is arranged outside the housing and the lower end (311) is arranged in the second chamber (12).

[0084] In a third dependent embodiment which may be combined with the second dependent embodiment, the upper end (312) is arranged above the lower end (311) when the power transmission device is arranged in the normal operating position.

[0085] In a fourth dependent embodiment, which may be combined with any of the second or third dependent embodiments, the second chamber comprises a fluid reservoir, wherein the lower end (311) is disposed in the reservoir. The term "reservoir" herein refers to a defined space arranged to hold a quantity of fluid. The upper end (312) is disposed above the reservoir.

[0086] The upper end may here be arranged outside and / or above the sump.The main purpose of the sump is to allow any fluid entering the second chamber to remain in the sump until a higher pressure within the housing forces the fluid out through the first fluid connection.

[0087] In a fifth dependent embodiment which may be combined with the sixth embodiment or any of the dependent embodiments, the second chamber comprises a heat source.

[0088] In an embodiment, the heat source is an electric motor (200).

[0089] In a sixth dependent embodiment which may be combined with any of the dependent embodiments, the first fluid connection comprises a tube or a pipe extending above the mechanical power transmission device.

[0090] In a first embodiment of the system, the invention is a pedal-propelled vehicle comprising a ventilated mechanical power transmission device according to any one of the devices of the above embodiments.

[0091] In a first related embodiment, the first shaft (41) is a shift shaft.

[0092] In a second related embodiment, the first shaft (41) is a crankshaft.

[0093] In a system of a second embodiment, which may be combined with the system of the first embodiment, a pedal-propelled vehicle includes an electric engine (200).

[0094] In a first related embodiment, the electric motor is arranged to drive the first shaft (41).

[0095] In a second related embodiment, the electric motor is arranged to drive the second shaft (42).

[0096] In the system of the third embodiment, which can be combined with the sixth dependent embodiment of the device of the sixth embodiment, the tube or duct extends into the seat tube of the pedal-propelled vehicle.

[0097] In a system of a third embodiment, which may be combined with the system of the second embodiment, the electric motor (200) is arranged in the housing (10) above the level (L) of the liquid lubricant when the pedal-propelled vehicle is arranged in a normal upright driving position.

[0098] In the exemplary embodiments, a plurality of features and details are shown in combination. The fact that several features are described with respect to a particular example should not be interpreted as implying that these features must necessarily be included together in all embodiments of the present invention. On the contrary, the features described with reference to different embodiments should not be interpreted as mutually exclusive. As will be readily understood by those skilled in the art, embodiments that are combined with any subset of the features described herein and that are not explicitly interdependent have been considered by the inventors and are part of the intended disclosure. However, explicitly describing all of these embodiments would not contribute to understanding the principles of the present invention, and therefore, for simplicity or brevity, some feature arrangements have been omitted.

Claims

1. A ventilated mechanical power transmission device (1), comprising: - housing (10); - a first seal (51); - a first shaft (41) extending through the first seal (51) and through the wall of the housing (10), wherein the first shaft (41) is configured to rotate relative to the housing (10); and - a vent channel (30) configured to release the pressure difference between the interior and the exterior of the housing (10) at any three-dimensional rotational position of the mechanical power transmission device (1), wherein the housing (10) is configured to be partially filled with a liquid lubricant, wherein the vent channel (30) has a first end (31) and a second end (32), wherein the first end (31) is external to the housing and the second end (32) is internal to the housing, and wherein the second end is configured to remain above the liquid lubricant in any three-dimensional rotational position of the mechanical power transmission device; and The housing (10) comprises a first chamber and a second chamber, and the ventilation channel (30) comprises a second fluid connector (302), the second fluid connector comprising a second end (32) and an upper end (312) opposite to the second end, wherein the second end is arranged in the first chamber (11) and the upper end is arranged in the second chamber (12).

2. The ventilated mechanical power transmission device (1) according to claim 1, wherein: The first shaft (41) is hollow, and at least some portion of the first shaft (41) constitutes at least a portion of the ventilation channel.

3. The ventilated mechanical power transmission device (1) according to claim 2, wherein: The second end (32) is a vent hole located in the wall of the first shaft (41).

4. The ventilated mechanical power transmission device (1) according to claim 3, wherein: The vent hole is arranged at a middle position between the inner walls of the housing.

5. The ventilated mechanical power transmission device (1) according to claim 3 or 4, comprising a hollow second shaft (42), the second shaft being coaxially arranged outside the first shaft (41) and configured to rotate relative to the first shaft (41), wherein The second shaft (42) includes a first bore (33), wherein a fluid path is maintained between the first bore and the vent hole in the first shaft, the fluid path being independent of the rotational position between the first shaft and the second shaft.

6. The ventilated mechanical power transmission device (1) according to claim 5, wherein: The first shaft (41) includes a guide cam (43) configured to radially guide the first shaft (41) relative to an interior of the second shaft (42), wherein the guide cam (43) is arranged between a main hole of the second end and the first hole and is further configured to allow fluid to flow between the main hole and the first hole.

7. The ventilated mechanical power transmission device (1) according to claim 5, wherein: The second shaft (42) includes a second hole (34), wherein the first hole and the second hole are arranged on opposite sides of the vent hole of the first shaft (41).

8. The ventilated mechanical power transmission device (1) according to claim 7, comprising a second seal (52), wherein: The first seal and the second seal are disposed between the first shaft and the second shaft outside the second bore and the first bore, respectively.

9. The ventilated mechanical power transmission device (1) according to claim 1, wherein the vent channel comprises a first fluid connector (301), and the first fluid connector comprises the first end (31).

10. The ventilated mechanical power transmission device (1) according to claim 9, wherein the first fluid connection comprises a lower end (311) opposite to the first end, wherein: The first end (31) is arranged outside the housing, and the lower end (311) is arranged in the second chamber (12).

11. The ventilated mechanical power transmission device (1) according to claim 10, wherein the upper end (312) is located above the lower end (311) when the power transmission device is arranged in a normal operating position.

12. The ventilated mechanical power transmission device (1) according to claim 10 or 11, wherein the second chamber comprises a fluid storage tank, wherein The lower end (311) is arranged in the storage tank.

13. The ventilated mechanical power transmission device (1) according to claim 10 or 11, wherein the second chamber comprises an electric motor (200).

14. The ventilated mechanical power transmission device (1) according to claim 9, wherein the first fluid connection comprises a tube or pipe extending above the mechanical power transmission device.

15. A pedal-propelled vehicle comprising a ventilated mechanical power transmission device (1) according to any one of claims 1 to 14.

Images