CN117780812A

CN117780812A - Hydraulic actuator, clutch comprising same and vehicle

Info

Publication number: CN117780812A
Application number: CN202211159500.0A
Authority: CN
Inventors: 刘福仁; 叶继海; 颜帮华; 陈睿进; 陆明浩
Original assignee: FTE Automotive Taicang Co Ltd
Current assignee: FTE Automotive Taicang Co Ltd
Priority date: 2022-09-22
Filing date: 2022-09-22
Publication date: 2024-03-29
Also published as: WO2024061168A1

Abstract

The present disclosure relates to a hydraulic actuator, comprising: a hydraulic linear actuator, a driving arm movable between a first position and a second position, a lock mechanism capable of locking the driving arm in the first or second position, and a control oil passage for controlling the hydraulic linear actuator. The control oil path comprises a first oil path for driving the driving arm from the first position to the second position; a second oil passage for driving the drive arm from the second position to the first position; and a bidirectional pump for selectively supplying hydraulic oil to the first or second oil passages to provide driving hydraulic pressure. The disclosure also relates to a clutch comprising such a hydraulic actuator and a vehicle comprising said clutch.

Description

Hydraulic actuator, clutch comprising same and vehicle

Technical Field

The present disclosure relates to a hydraulic actuator and a clutch including the hydraulic actuator, and a vehicle including the clutch.

Background

Various components of the vehicle need to be switched between various operating states, such as a transmission in the driveline needs to be switched between different gear ratios, a clutch in the driveline needs to be switched between an engaged state and a disengaged state, and a park lock device needs to be switched between a locked state and an unlocked state. Such switching of the operating state is typically performed by an actuator that is movable between two or more operating positions.

Common actuators include hydraulic actuators. The hydraulic actuator has the advantages of larger torque and low cost. However, the hydraulic actuator needs to be driven by a pump to supply power for performing state switching, and the hydraulic actuator needs to be actuated by filling the oil passage with hydraulic oil. Therefore, when the hydraulic actuator is used, the interval from the instruction to the completion of the state switching is long, that is, the response time of the hydraulic actuator is long. The hydraulic actuator is thus not suitable for applications where a high response speed is required.

Thus, there is a need for a hydraulic actuator having a shorter response time.

Disclosure of Invention

In view of the above-mentioned problems and needs, it is an object of the present disclosure to provide a hydraulic actuator, a clutch, and a vehicle, which solve the above-mentioned problems and bring about other technical effects due to the following technical features.

The hydraulic actuator according to the present disclosure includes: a hydraulic linear actuation mechanism comprising a drive arm movable between a first position and a second position; a lock mechanism capable of locking the drive arm in the first position or the second position; and the control oil way is used for controlling the hydraulic linear actuating mechanism. The control oil path comprises a first oil path for driving the driving arm from a first position to a second position; a second oil passage for driving the drive arm from the second position to the first position; and a bidirectional pump for selectively supplying hydraulic oil to the first oil passage or the second oil passage to provide driving hydraulic pressure. When the drive arm is locked in the first position, the bidirectional pump supplies hydraulic oil to a first oil passage at a first pressure so that the first oil passage is filled with hydraulic oil. When the drive arm is unlocked to move from the first position to the second position, the bi-directional pump supplies hydraulic oil to the first oil passage at a second pressure that is equal to or higher than the first pressure to drive the drive arm from the first position to the second position.

It is an object of the present disclosure to provide a hydraulic actuator having a shorter response time. The hydraulic actuator according to the present disclosure has already filled the first oil passage with hydraulic oil when the drive arm is locked in said first position. When the drive arm is unlocked to move from the first position to the second position, hydraulic oil does not need to be refilled into the first oil passage, but the drive arm can be directly driven. In this way, the time required for the drive arm of the hydraulic linear actuation mechanism to move from the first position to the second position can be substantially reduced, i.e. the response time of the hydraulic actuator to perform the movement from the first position to the second position is substantially reduced.

Hydraulic actuators according to the present disclosure may also have one or more of the following features, alone or in combination.

According to one embodiment of the present disclosure, when the drive arm is locked in the second position, the bi-directional pump supplies oil to the first oil passage at a third pressure so that the first oil passage is filled with hydraulic oil. When the driving arm is unlocked to move from the second position to the first position, the bi-directional pump supplies oil to the second oil passage at a fourth pressure, which is equal to or higher than the third pressure, to drive the driving arm from the second position to the first position. Optionally, the third pressure is equal to the first pressure and/or the fourth pressure is equal to or less than the second pressure.

According to the above feature, even when the drive arm is locked in the second position, the bi-directional pump supplies oil to the first oil passage. This makes it necessary for the hydraulic oil to fill the second oil passage before the drive arm can be driven when the drive arm is unlocked to move from the second position to the first position. The time required for the drive arm of the hydraulic linear actuation mechanism to move from the second position to the first position is still long. That is, the response time of the hydraulic actuator to perform the movement from the second position to the first position is still long, and the hydraulic actuator is asymmetrical. Such an asymmetric hydraulic actuator is particularly suitable for situations where the response times required for switching between the two operating states are different, such as switching of a clutch between an engaged state and a disengaged state.

According to one embodiment of the present disclosure, the control oil passage further includes a cooling oil passage for cooling hydraulic oil, which is selectively connected to the first oil passage through an on-off valve.

According to one embodiment of the present disclosure, when the driving arm is locked in the first position or the second position, the switching valve is opened so that the cooling oil passage communicates with the first oil passage, hydraulic oil enters the cooling oil passage from the first oil passage to be cooled, and when the driving arm is unlocked to move between the first position and the second position, the switching valve is closed to disconnect the cooling oil passage from the first oil passage.

According to the above feature, when the drive arm is locked, the hydraulic oil can be cooled by entering the cooling oil passage. And when the driving arm is unlocked to move between the first position and the second position, hydraulic oil cannot enter the cooling oil path. In this way, the time for driving the driving arm to move by the hydraulic oil is not prolonged because the hydraulic oil enters the cooling oil path, and the response time of the hydraulic actuator is not adversely affected by the existence of the cooling oil path.

According to one embodiment of the present disclosure, the switch valve and the locking mechanism are powered by the same power source. Thus, the number of power sources of the hydraulic actuator can be saved.

According to one embodiment of the present disclosure, when the drive arm is locked in the second position, the bi-directional pump supplies oil to the second oil passage at a third pressure so that the second oil passage is filled with hydraulic oil. When the driving arm is unlocked to move from the second position to the first position, the bi-directional pump supplies oil to the second oil passage at a fourth pressure, which is equal to or higher than the third pressure, to drive the driving arm from the second position to the first position. Optionally, the third pressure is equal to the first pressure and/or the fourth pressure is equal to or less than the second pressure.

In this embodiment, the bi-directional pump supplies oil to the second oil passage when the drive arm is locked in the second position. This makes it unnecessary for the hydraulic oil to fill the second oil passage when the drive arm is unlocked to move from the second position to the first position, but the drive arm can be directly driven. In this way, the time required for the drive arm of the hydraulic linear actuation mechanism to move from the second position to the first position can be substantially reduced, i.e. the response time of the hydraulic actuator to perform the movement from the second position to the first position is substantially reduced. That is, the response time of the hydraulic actuator to perform bi-directional movement between the first and second positions is substantially reduced, and the hydraulic actuator is symmetrical. This symmetrical hydraulic actuator is particularly suitable for situations where a short response time is required for switching between the two operating states.

According to one embodiment of the present disclosure, the control oil passage further includes a cooling oil passage for cooling hydraulic oil, which is selectively connected to the first oil passage and the second oil passage through an on-off valve.

According to one embodiment of the present disclosure, when the drive arm is locked in the first position, the cooling oil passage is communicated with the first oil passage and disconnected from the second oil passage, and hydraulic oil is cooled from the first oil passage into the cooling oil passage. When the drive arm is locked in the second position, the cooling oil passage is communicated with a second oil passage and disconnected from the first oil passage, hydraulic oil enters the cooling oil passage from the second oil passage to be cooled, and when the drive arm is unlocked to move between the first position and the second position, the cooling oil passage is disconnected from both the first oil passage and the second oil passage.

According to one embodiment of the disclosure, the control oil passage further includes an oil reservoir, and the first oil passage and the second oil passage are connected to the oil reservoir through check valves, respectively, such that hydraulic oil can only flow from the oil reservoir into the first oil passage or the second oil passage. The reservoir may store a quantity of hydraulic oil, ensuring that there is sufficient hydraulic oil available to fill the first and second oil passages and to drive the drive arm.

According to one embodiment of the disclosure, the control oil passage further includes a filter arranged between the oil reservoir and the check valve for filtering hydraulic oil flowing out from the oil reservoir.

According to one embodiment of the present disclosure, the one-way valve and filter are integrated in the bi-directional pump.

According to one embodiment of the present disclosure, the hydraulic linear actuation mechanism is a hydraulic cylinder and the locking mechanism is a locking solenoid.

The present disclosure also provides a clutch comprising a hydraulic actuator as described above. The hydraulic actuator is configured to perform a switch of the clutch between an engaged state and a disengaged state, wherein the clutch is in the disengaged state when the drive arm is in the first position and the clutch is in the engaged state when the drive arm is in the second position.

The present disclosure also provides a vehicle comprising a clutch as described above.

Drawings

The above and other features and advantages of the present disclosure will become more apparent from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, which are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. The following drawings are not intended to be drawn to scale on actual dimensions, emphasis instead being placed upon illustrating the principles of the disclosure. In the figure:

FIG. 1 illustrates a schematic view of a hydraulic actuator according to one embodiment of the present disclosure.

Fig. 2A-2D show schematic views of a hydraulic actuator according to the present disclosure in different operating states.

The same or similar parts are designated by the same reference numerals throughout the drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "a," "an," or "the" and similar referents used in the specification and claims of the present disclosure are not to be construed to limit the number of equivalents, but rather to mean that there is at least one. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "first," "second," and the like in the description and in the claims, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

Various embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. Here, it is to be noted that in the drawings, the same reference numerals are given to constituent parts having substantially the same or similar structures and functions, and repeated description thereof will be omitted.

FIG. 1 illustrates a schematic diagram of one embodiment of a hydraulic actuator 100 according to the present disclosure. As shown in fig. 1, the hydraulic actuator 100 includes: the hydraulic linear actuation mechanism 1, the lock mechanism 3, and a control oil passage 10 for controlling the hydraulic linear actuation mechanism 1. The hydraulic linear actuation mechanism 1 is actuatable by hydraulic oil supplied by a control oil circuit 10 and comprises a drive arm 2 movable between a first position and a second position under hydraulic oil actuation. The driving arm 2 is in a first position and a second position, respectively, for placing the external component in different operating states. For example, the first and second positions of the drive arm 2 may cause the clutch to be in a disengaged and engaged state, respectively. The locking mechanism 3 may lock the driving arm 2 in the first position or the second position by a locking lever. In the embodiment shown in fig. 1, the hydraulic linear actuation mechanism 10 is a hydraulic cylinder, and the locking mechanism 3 is a solenoid with a locking. When the lock solenoid is not energized or the energizing current is small, the lock mechanism 3 is closed, the lock lever is extended under the elastic bias, and the drive arm 2 is locked in the first position or the second position. When the locking solenoid is energized with a sufficiently large current, the locking mechanism 3 is opened and the locking lever is retracted against the spring bias under the influence of the magnetic force, the drive arm 2 being movable under hydraulic oil actuation between a first position and a second position.

The control oil passage 10 includes a first oil passage 11, a second oil passage 12, and a bidirectional pump 13. The first oil passage 11 is connected to the hydraulic linear actuation mechanism 1, the pressure of the hydraulic oil in the first oil passage 11 is used to drive the drive arm 2 from the first position to the second position, and the second oil passage 12 is connected to the hydraulic linear actuation mechanism 1 for driving the drive arm 2 from the second position to the first position. The bidirectional pump 13 is rotatable in two rotational directions (e.g., clockwise and counterclockwise) to selectively supply hydraulic oil to the first oil passage 11 or the second oil passage 12, providing drive hydraulic pressure.

The control oil passage 10 further includes an oil reservoir 16 for storing hydraulic oil, and a check valve 17 and a filter 18. In the embodiment of fig. 1, the control oil passage 10 includes two check valves 17 and two filters 18. The first oil passage 11 and the second oil passage 12 are connected to the reservoir 16 through respective check valves 17 and filters 18, respectively. The check valve 17 allows hydraulic oil to flow only from the reservoir 16 into the first oil passage 11 or the second oil passage 12, and not in the reverse direction. The filter 18 filters the hydraulic oil flowing from the reservoir 16 to prevent impurities from blocking the first and second oil passages. The non-return valve 17 and the filter 18 may also be integrated in the bi-directional pump 13.

The control oil passage 10 further includes a cooling oil passage 14 for cooling hydraulic oil. In the embodiment shown in fig. 1, the cooling oil passage 14 is selectively connected to the first oil passage 11 through an on-off valve 15. That is, the on-off valve 15 may communicate the first oil passage 11 with the cooling oil passage 14 or disconnect the first oil passage 11 from the cooling oil passage 14, as needed. The hydraulic oil cooled by the cooling oil passage 14 may be returned to the reservoir 16 via an external passage (not shown) for recycling.

Fig. 2A-2D show schematic views of the hydraulic actuator 100 of fig. 1 in different operating states a-D.

In the operating state a of the hydraulic actuator 100 shown in fig. 2A, the lock mechanism 3 is closed, the drive arm 2 is locked in the first position, the bidirectional pump 13 is rotated in the forward direction (clockwise direction shown in fig. 2A), and the hydraulic oil is supplied to the first oil passage 11 at the first pressure so that the first oil passage 11 is filled with the hydraulic oil. Meanwhile, in the operating state a, the on-off valve 15 is opened so that the first oil passage 11 communicates with the cooling oil passage 14, and the hydraulic oil enters the cooling oil passage 14 from the first oil passage 11 to be cooled. In applications where the hydraulic actuator 100 is used to perform a shift of the clutch between an engaged state and a disengaged state, such an operating state a may correspond to the clutch being in the disengaged state.

In the operating state B of the hydraulic actuator 100 shown in fig. 2B, the bidirectional pump 13 is rotated in the forward direction, and hydraulic oil is supplied to the first oil passage 11 at a second pressure equal to or higher than the first pressure. The lock mechanism 3 is opened, and the drive arm 2 is moved from the first position to the second position by the drive of the second pressure. Since the first oil passage 11 is already filled with hydraulic oil in the operating state a, in the operating state b, the hydraulic oil does not need to be refilled into the first oil passage 11, but the drive arm 2 can be directly driven. The response time of the movement of the drive arm 2 from the first position to the second position is substantially shortened. Meanwhile, in the operating state b, the on-off valve 15 is closed, so that the first oil passage 11 is disconnected from the cooling oil passage 14, and hydraulic oil cannot enter the cooling oil passage 14 from the first oil passage 11. In this way, the hydraulic oil is used only to drive the drive arm 2 in the operating state b, avoiding the pressure loss in the first oil passage 11 caused by communication with the cooling oil passage 14, which is more advantageous in shortening the response time. Such an operating state a may correspond to a process of switching the clutch from the disengaged state to the engaged state when the clutch is to be switched between the engaged state and the disengaged state. The reduced response time of the movement of the drive arm 2 from the first position to the second position corresponds to a reduced response time of the clutch switching from the disengaged state to the engaged state.

After the drive arm 2 reaches the second position, the lock mechanism 3 is closed to lock the drive arm 2 in the second position. The hydraulic actuator 100 is shifted from the operating state b to the operating state C shown in fig. 2C.

In the operating state c, the lock mechanism 3 is closed, the drive arm 2 is locked in the second position, the bi-directional pump 13 is rotated in the forward direction, and the hydraulic oil is supplied to the first oil passage 11 at the third pressure, so that the first oil passage 11 is filled with the hydraulic oil. Optionally, the third pressure is equal to the first pressure. Meanwhile, in the operating state c, the on-off valve 15 is opened so that the first oil passage 11 communicates with the cooling oil passage 14, and the hydraulic oil enters the cooling oil passage 14 from the first oil passage 11 to be cooled. In applications where the hydraulic actuator 100 is used to perform a shift of the clutch between an engaged state and a disengaged state, such an operating state c may correspond to the clutch being in an engaged state.

In the operating state D of the hydraulic actuator 100 shown in fig. 2D, the bidirectional pump 13 is rotated in the reverse direction, and hydraulic oil is supplied to the second oil passage 12 at a fourth pressure equal to or higher than the third pressure. Optionally, the fourth pressure is equal to or less than the second pressure. The lock mechanism 3 is opened, and the drive arm 2 is moved from the second position to the first position by the drive of the fourth pressure. Since the bi-directional pump 13 does not supply hydraulic oil to the second oil passage 12 in the operating state c, the hydraulic oil needs to fill the second oil passage 12 first in the operating state d to drive the drive arm 2. Thus, the response time of the drive arm 2 moving from the second position to the first position is greater than the response time of the drive arm moving from the first position to the second position. In applications where the hydraulic actuator 100 is used to perform a shift of the clutch between an engaged state and a disengaged state, such an operating state d may correspond to a process of shifting the clutch from the engaged state to the disengaged state. Since the response time for the clutch to switch from the engaged state to the disengaged state is not as high as the response time for the clutch to switch from the disengaged state to the engaged state, a larger response time for the drive arm 2 of the hydraulic actuator 100 to move from the second position to the first position is sufficient. Furthermore, since there is no fluid connection between the cooling oil passage 14 and the second oil passage 12, hydraulic oil does not enter the cooling oil passage 14 in the operating state d.

After the drive arm 2 reaches the first position, the lock mechanism 3 is closed to lock the drive arm 2 in the first position. The hydraulic actuator 100 is reconverted from the operating state d to the operating state a shown in fig. 2A.

In both the locked operating states a and c of the drive arm 2, the hydraulic oil enters the cooling oil passage 14 and is cooled. In the operating states b and d in which the drive arm 2 moves, the hydraulic oil does not enter the cooling oil passage 14, and cooling is not performed. However, the duration of the operating states b and d in which the inability to cool the hydraulic oil does not cause the temperature of the hydraulic oil to rise beyond the threshold value is comparatively short.

When the bi-directional pump 13 supplies oil to one of the first oil passage 11 and the second oil passage 12, a suction effect is generated in the other oil passage so as to maintain a certain degree of vacuum. In this way, when the rotation direction of the bidirectional pump 13 is changed to supply oil to the other oil passage, the vacuum action generates suction force to the hydraulic oil, so that the other oil passage can be filled more quickly. In the operation state a-c of the hydraulic actuator 100, the bidirectional pump 13 continues to supply oil to the first oil passage 11, and the second oil passage 12 is sucked into a vacuum state. When the hydraulic actuator 100 is changed from the operating state c to the operating state d, the bidirectional pump 13 is changed from the normal rotation to the reverse rotation to supply the oil to the second oil passage 12, and the vacuum state of the second oil passage 12 can increase the speed at which the hydraulic oil fills the second oil passage 12. In the operating state d of the hydraulic actuator 100, the first oil passage 11 is suctioned into a vacuum state. When the hydraulic actuator 100 is changed from the operating state d to the operating state a, the bidirectional pump 13 is changed from reverse rotation to forward rotation to supply the first oil passage 11 with oil, and the vacuum state of the first oil passage 11 can increase the speed at which the hydraulic oil fills the first oil passage 11.

Further, as described above, in the operating state d, the first oil passage 11 is sucked into a vacuum state. In order to avoid the hydraulic oil from flowing back from the cooling oil passage 14 to the first oil passage 11, the on-off valve 15 is in a closed state. Thus, in both the operating states a and c in which the lock mechanism 3 is closed, the on-off valve 15 is maintained in the open state, and in both the operating states b and d in which the lock mechanism 3 is open, the on-off valve 15 is in the closed state. Due to this relationship between the two, the on-off valve 15 and the lock mechanism 3 can be supplied with power from the same power source. When the power supply supplies a large current, the lock mechanism 3 is opened and the on-off valve 15 is closed. When the power supply is supplied with a small current, the lock mechanism 3 is closed and the on-off valve 15 is opened. For example, when the hydraulic actuator 100 is used in a vehicle, the on-off valve 15 and the lock mechanism 3 may be powered by the same 12V port of the inverter of the vehicle.

An asymmetric hydraulic actuator 100 is described above in connection with the accompanying drawings, which is particularly suited for situations where the response time required for switching between two operating states is different.

The control oil passage 10 may also be modified to adjust the hydraulic actuator 100 to a symmetrical hydraulic actuator 100 (not shown in the drawings). For example, in the operating state c, the bidirectional pump 13 may be reversely rotated to supply the second oil passage 12 with oil so that the second oil passage 12 is filled with the hydraulic oil. Thus, when the operating state c is shifted to the operating state d, the hydraulic oil can directly drive the drive arm 2 from the second position to the first position without refilling the second oil passage 12. The response time of the movement of the drive arm 2 from the second position to the first position is also shortened.

In such a symmetrical hydraulic actuator, it is preferable that the hydraulic oil is cooled by the cooling oil passage 14 also when the drive arm 2 is locked, and is disconnected from the cooling oil passage 14 when the drive arm 2 moves. For this reason, the communication relationship between the cooling oil passage 14 and the first and second oil passages 11 and 12 needs to be adjusted. For example, the cooling oil passage 14 may be connected to the first oil passage 11 and the second oil passage 12 through different on-off valves, respectively. When the drive arm 2 is locked in the first position (corresponding to the operation state a), the cooling oil passage 14 communicates with the first oil passage 11 and is disconnected from the second oil passage 12, and the hydraulic oil enters the cooling oil passage 14 from the first oil passage 11 to be cooled; when the drive arm 2 is locked in the second position (corresponding to the operating state c), the cooling oil passage 14 communicates with the second oil passage 12 and is disconnected from the first oil passage 11, and the hydraulic oil enters the cooling oil passage 14 from the second oil passage 12 to be cooled; and the cooling oil passage 14 may be disconnected from both the first oil passage 11 and the second oil passage 12 when the drive arm 2 is unlocked to move between the first position and the second position.

According to another aspect of the present disclosure, a clutch is presented comprising a hydraulic actuator 100 as described above for performing a switching of the clutch between an engaged state and a disengaged state. In particular, the clutch is in a disengaged state when the drive arm 2 of the hydraulic actuator 100 is in the first position and in an engaged state when the drive arm 2 of the hydraulic actuator 100 is in the second position.

According to another aspect of the present disclosure, a vehicle is presented that includes a transmission as previously described. The vehicle may be an electrified vehicle (Electrified Vehicle), such as a pure electric vehicle (BEV, battery Electric Vehicle), a hybrid electric vehicle (HEV, hybrid Electric Vehicle), a Plug-in hybrid electric vehicle (PHEV, plug-in Hybrid Electric Vehicle), an extended range electric vehicle (Range extended EV), a fuel cell vehicle (FCEV, fuel Cell Electric Vehicle). The vehicle may also be a hydrogen-powered vehicle.

Certain features, structures, or characteristics of one or more embodiments of the present disclosure may be combined as suitable.

The foregoing is illustrative of the present disclosure and is not to be construed as limiting thereof. Although a few exemplary embodiments of this disclosure have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this disclosure. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is to be understood that the foregoing is illustrative of the present disclosure and that the present disclosure is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the disclosure.

Claims

1. A hydraulic actuator, the hydraulic actuator comprising:

a hydraulic linear actuation mechanism comprising a drive arm movable between a first position and a second position,

a lock mechanism capable of locking the drive arm in the first position or the second position;

a control oil path for controlling the hydraulic linear actuating mechanism (1), comprising

A first oil passage for driving the drive arm from a first position to a second position;

a second oil passage for driving the drive arm from the second position to the first position;

a bi-directional pump for selectively supplying hydraulic oil to the first oil passage or the second oil passage, providing a drive hydraulic pressure,

wherein when the drive arm is locked in the first position, the bidirectional pump supplies hydraulic oil to the first oil passage at a first pressure so that the first oil passage is filled with hydraulic oil,

when the drive arm is unlocked to move from the first position to the second position, the bi-directional pump supplies hydraulic oil to the first oil passage at a second pressure that is equal to or higher than the first pressure to drive the drive arm from the first position to the second position.

2. The hydraulic actuator of claim 1, wherein the hydraulic actuator is configured to,

when the driving arm is locked at the second position, the bi-directional pump supplies oil to the first oil passage at a third pressure so that the first oil passage is filled with hydraulic oil,

when the drive arm is unlocked to move from the second position to the first position, the bi-directional pump supplies oil to the second oil passage at a fourth pressure that is equal to or higher than the third pressure to drive the drive arm from the second position to the first position.

3. The hydraulic actuator of claim 1 or 2, wherein,

the control oil passage further includes a cooling oil passage for cooling hydraulic oil, which is selectively connected to the first oil passage through an on-off valve.

4. The hydraulic actuator of claim 3, wherein,

when the drive arm is locked in the first position or the second position, the switch valve is opened so that the cooling oil passage communicates with the first oil passage, hydraulic oil enters the cooling oil passage from the first oil passage to be cooled,

when the drive arm is unlocked to move between the first position and the second position, the switching valve is closed to disconnect the cooling oil passage from the first oil passage.

5. The hydraulic actuator of claim 3, wherein,

the switch valve and the locking mechanism are powered by the same power supply.

6. The hydraulic actuator of claim 1, wherein the hydraulic actuator is configured to,

when the driving arm is locked at the second position, the bi-directional pump supplies oil to the second oil passage at a third pressure so that the second oil passage is filled with hydraulic oil,

when the driving arm is unlocked to move from the second position to the first position, the bi-directional pump supplies oil to the second oil passage at a fourth pressure, which is equal to or higher than the third pressure, to drive the driving arm from the second position to the first position.

7. The hydraulic actuator of claim 2 or 6, wherein,

the third pressure is equal to the first pressure and/or the fourth pressure is equal to or less than the second pressure.

8. The hydraulic actuator of claim 1 or 6, wherein,

the control oil passage further includes a cooling oil passage for cooling hydraulic oil, which is selectively connected to the first oil passage and the second oil passage through an on-off valve.

9. The hydraulic actuator of claim 8, wherein the hydraulic actuator is configured to,

when the driving arm is locked at the first position, the cooling oil passage is communicated with the first oil passage and disconnected with the second oil passage, hydraulic oil enters the cooling oil passage from the first oil passage to be cooled,

when the driving arm is locked at the second position, the cooling oil passage is communicated with a second oil passage and disconnected from the first oil passage, the second oil passage enters the cooling oil passage to be cooled, and

when the drive arm is unlocked to move between the first and second positions, the cooling oil passage is disconnected from both the first and second oil passages.

10. The hydraulic actuator of claim 1, wherein the hydraulic actuator is configured to,

the control oil passage further includes an oil reservoir to which the first oil passage and the second oil passage are connected through check valves, respectively, so that hydraulic oil can only flow from the oil reservoir into the first oil passage or the second oil passage.

11. The hydraulic actuator of claim 10, wherein the hydraulic actuator is configured to,

the control oil passage further includes a filter disposed between the oil reservoir and the check valve for filtering hydraulic oil flowing out from the oil reservoir.

12. The hydraulic actuator of claim 11, wherein the hydraulic actuator is configured to,

the one-way valve and filter are integrated in the bi-directional pump.

13. The hydraulic actuator of claim 1, wherein the hydraulic actuator is configured to,

the hydraulic linear actuation mechanism is a hydraulic cylinder and the locking mechanism is a locking solenoid.

14. A clutch comprising a hydraulic actuator according to any one of claims 1 to 13 for performing switching of the clutch between an engaged state and a disengaged state, wherein the clutch is in the disengaged state when the drive arm is in a first position and the clutch is in the engaged state when the drive arm is in a second position.

15. A vehicle comprising a clutch according to claim 14.