An electric clutch actuator with variable engagement function

Abstract

This invention relates to the field of clutch technology and discloses an electric clutch actuator with a speed-changing engagement function, comprising: a worm gear rotatably mounted on the actuator housing and driven to rotate by a drive motor; a worm gear shaft coaxially connected to the worm gear, on which a first gear ring and a second gear ring are coaxially arranged, the pitch circle radius of the first gear ring being smaller than that of the second gear ring; and a rack shaft connected to a pressure plate, the rack shaft having first meshing teeth corresponding to the first gear ring and second meshing teeth corresponding to the second gear ring. This invention, without changing the clutch structure or the drive motor speed, utilizes the drive motor and two gear rings with different pitch circle radii to drive the pressure plate, initially slowly and then rapidly, achieving a slower speed during the contact phase between the friction plate and the steel plate and a faster speed during the clamping phase. It features a compact structure, high reliability, and is particularly suitable for heavy-load starts, frequent gear shifts, and other operating conditions requiring high clutch engagement quality.

Description

Technical Field

[0001] This invention relates to the field of clutch technology, and in particular to an electric clutch actuator with a speed-changing engagement function. Background Technology

[0002] Multi-plate clutches are widely used in heavy-duty vehicles such as special vehicles, mining vehicles, and engineering vehicles for high-altitude and cold regions. Existing multi-plate clutch actuators are typically hydraulic or electric. Hydraulic actuators use hydraulic oil to push the pressure plate, but hydraulic oil has viscosity-temperature characteristics. This means that the oil viscosity changes significantly in low and high temperature environments, leading to unstable operating characteristics. Specifically, in low-temperature environments, the oil viscosity increases sharply or even solidifies, causing sluggish response or complete failure of the actuator, and may even cause the oil lines to freeze and crack. In high-temperature environments, the oil viscosity decreases, reducing control accuracy and making it prone to engagement shocks, which is also detrimental to clutch control.

[0003] Electric actuators are simpler in structure and offer faster control response compared to hydraulic actuators, and are unaffected by the viscosity-temperature characteristics of hydraulic oil. However, in an electric clutch actuator, the axial movement of the pressure plate is constant during a single engagement stroke. This "constant speed engagement" method cannot meet the speed differences required at different stages of clutch engagement. Specifically, in the initial stage of clutch engagement, the gap between the friction plates and the steel plates gradually decreases until they contact each other. At this point, the pressure plate needs to be pushed at a lower speed to reduce system impact and improve engagement smoothness. After the friction plates contact and begin to transmit torque, the pressure plate needs to be pressed down quickly to shorten the slippage time of the driving and driven parts and reduce frictional heat generation.

[0004] In view of this, how to provide an electric clutch actuator that can make the friction plate and the steel plate contact at low speed in the initial stage of clutch engagement and press them together at high speed after the friction plate and the steel plate contact each other is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide an electric clutch actuator with a variable speed engagement function to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides an electric clutch actuator with a speed-changing engagement function, comprising: The worm gear is rotatably mounted on the housing of the actuator and is driven to rotate by a drive motor. A worm gear shaft is coaxially connected to the worm gear, and a first gear ring and a second gear ring are coaxially arranged on the worm gear shaft. The pitch circle radius of the first gear ring is smaller than that of the second gear ring. The rack shaft clutch has a pressure plate for pushing the friction plate into contact with the steel plate. The rack shaft is connected to the pressure plate. The rack shaft is provided with a first meshing tooth corresponding to the first gear ring and a second meshing tooth corresponding to the second gear ring. When the drive motor drives the worm gear to rotate, the worm gear shaft first connects to the drive pressure plate through the first gear ring and the first meshing tooth to push the friction plate at a speed of v1. When the first gear ring separates from the first meshing tooth, the friction plate and the steel plate are in contact. At this time, the second gear ring connects to the second meshing tooth, and the drive pressure plate pushes the friction plate and the steel plate to press together at a speed of v2, where v1 < v2.

[0007] Furthermore, it also includes: The worm gear is connected to the worm wheel drive, and the worm gear is connected to the output end of the drive motor through the worm shaft.

[0008] Furthermore, the first gear ring and the second gear ring are axially misaligned on the worm gear shaft.

[0009] Furthermore, the first gear ring has 20 teeth, the second gear ring has 25 teeth, the module of both the first and second gear rings is 10, and the pressure angle of both is 20°.

[0010] Furthermore, the number of teeth in both the first and second meshing teeth does not exceed three.

[0011] Furthermore, a support bearing is provided on the outer side of the worm shaft.

[0012] Furthermore, the clutch includes: A passive drum, wherein the steel sheet is connected to the passive drum via an external spline, and the passive drum is connected to a passive shaft; The active drum has friction plates connected to it via internal splines. The active drum is connected to the drive shaft, and the friction plates and steel plates are arranged at intervals. A pressure plate is coaxially disposed on the outside of the active drum, and a needle roller bearing is disposed between the pressure plate and the active drum. The inner side of the rack shaft is connected to the drive shaft via a deep groove ball bearing, and the outer side is installed in a linear bearing. The linear bearing is installed in the gearbox, and a thrust bearing is disposed between the rack shaft and the pressure plate.

[0013] Furthermore, a first sleeve is provided between the needle roller bearing and the pressure plate, and a second sleeve is provided between the deep groove ball bearing and the rack shaft.

[0014] The present invention discloses the following technical effects: This invention, without altering the clutch structure or the drive motor speed, utilizes a drive motor and two gear rings with different pitch circle radii to sequentially drive the rack shaft. The rack shaft drives the pressure plate at a slower speed initially, followed by a faster speed. In the initial stage of clutch engagement, the first gear ring engages with the first meshing tooth, and the pressure plate gradually reduces the gap between the friction plate and the steel plate until they contact, improving engagement smoothness. After the friction plates contact and begin transmitting torque, the second gear ring engages with the second meshing tooth, and the pressure plate quickly presses down, shortening the slippage time of the driving and driven parts and reducing frictional heat generation. The structure is compact and highly reliable, making it particularly suitable for heavy-load starts, frequent gear shifts, and other conditions requiring high clutch engagement quality. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram showing the meshing of the first gear ring and the first meshing tooth. Figure 3 This is a schematic diagram showing the positions of the second gear ring and the second meshing tooth when the first gear ring is engaged with the first meshing tooth. Figure 4 This is a schematic diagram of a clutch; Figure 5 This is a schematic diagram showing the fit between the worm gear shaft and the rack shaft; Figure 6 This is the displacement-time curve of the pressure plate; Among them, 1. worm shaft; 2. support bearing; 3. worm wheel shaft; 4. worm wheel; 5. actuator housing; 6. drive shaft; 7. driven shaft; 8. pressure plate; 9. thrust bearing; 10. rack shaft; 11. first gear ring; 12. second sleeve; 13. driven drum; 14. drive drum; 15. needle roller bearing; 16. deep groove ball bearing; 17. first sleeve; 18. linear bearing; 19. second gear ring; 20. first meshing tooth; 21. second meshing tooth. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Those skilled in the art will understand that the term "comprising" as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figures 1 to 6 As shown, an embodiment of the present invention provides an electric clutch actuator with a speed-changing engagement function, comprising: The worm gear 4 is rotatably mounted on the actuator housing 5 and is driven to rotate by a drive motor. The worm gear shaft 3 is coaxially connected to the worm gear 4. A first gear ring 11 and a second gear ring 19 are coaxially arranged on the worm gear shaft 3. The pitch circle radius of the first gear ring 11 is smaller than the pitch circle radius of the second gear ring 19. The rack shaft 10 and the clutch have a pressure plate 8 for pushing the friction plate to engage with the steel plate. The rack shaft 10 is connected to the pressure plate 8. The rack shaft 10 is provided with a first meshing tooth 20 corresponding to the first gear ring 11 and a second meshing tooth 21 corresponding to the second gear ring 19. When the drive motor drives the worm gear 4 to rotate, the worm gear shaft 3 first connects to the drive pressure plate 8 through the first gear ring 11 and the first meshing tooth 20 to push the friction plate at a speed of v1. When the first gear ring 11 separates from the first meshing tooth 20, the friction plate and the steel plate are in contact. At this time, the second gear ring 19 connects to the second meshing tooth 21, and the drive pressure plate 8 pushes the friction plate and the steel plate to press together at a speed of v2, where v1 < v2.

[0021] In this embodiment, it also includes: The worm gear is connected to the worm wheel 4 for transmission, and the worm gear is connected to the output end of the drive motor through the worm shaft 1.

[0022] In this embodiment, the first gear ring 11 and the second gear ring 19 are arranged axially offset on the worm gear shaft 3.

[0023] In this embodiment, the first gear ring 11 has 20 teeth, the second gear ring 19 has 25 teeth, the module of both the first gear ring 11 and the second gear ring 19 is 10, and the pressure angle is 20°.

[0024] In this embodiment, the number of teeth of the first meshing tooth 20 and the second meshing tooth 21 does not exceed 3. Specifically, the number of teeth of the first meshing tooth 20 is 1 and the number of teeth of the second meshing tooth 21 is 3. This is because the actual stroke of the pressure plate 8 during the clutch engagement process is very short, so a small number of teeth can meet the stroke requirements of the pressure plate 8.

[0025] In this embodiment, a support bearing 2 is provided on the outer side of the worm shaft 1.

[0026] In this embodiment, the clutch includes: The passive drum 13 is connected to the steel sheet via an external spline, and the passive drum 13 is connected to the passive shaft 7. The driving drum 14 has friction plates connected to it via internal splines. The driving drum 14 is connected to the driving shaft 6, and the friction plates and steel plates are arranged at intervals. The pressure plate 8 is coaxially arranged on the outside of the driving drum 14, and a needle roller bearing 15 is provided between the pressure plate 8 and the driving drum 14. The inner side of the rack shaft 10 is connected to the driving shaft 6 via a deep groove ball bearing 16, and the outer side is installed in a linear bearing 18. The linear bearing 18 is installed in the gearbox, and a thrust bearing 9 is provided between the rack shaft 10 and the pressure plate 8.

[0027] In this embodiment, a first sleeve 17 is provided between the needle roller bearing 15 and the pressure plate 8, and a second sleeve 12 is provided between the deep groove ball bearing 16 and the rack shaft 10.

[0028] For the clutch, since the rotational speeds of the pressure plate 8 and the drive drum 14 are not always the same, a needle roller bearing 15 is required between them. Because the pressure plate 8 needs axial movement, a first sleeve 17 is added outside the needle roller bearing 15 to prevent the frictional force generated by this axial movement from damaging it. The first sleeve 17 is made of a material with a low coefficient of friction and is wear-resistant, reducing the impact of the frictional force generated by the axial displacement of the pressure plate 8 on the needle roller bearing 15. Similarly, there is also axial relative displacement between the rack shaft 10 and the deep groove ball bearing 16. To reduce the impact of the resulting frictional force on the deep groove ball bearing 16, a second sleeve 12 is added outside the deep groove ball bearing 16. The first sleeve 17 and the second sleeve 12 serve the same function. The rack shaft 10 is supported by linear bearings 18 at both ends and is installed in the gearbox housing. The rack shaft 10 slides freely axially through the linear bearings 18.

[0029] The specific work process is as follows: When the clutch is not engaged, the friction plates and steel plates are spaced apart, so no frictional torque is generated. At this time, both the friction plates and the driving drum 14 rotate with the driving shaft 6, while the driven shaft 7 does not rotate. When the clutch needs to be engaged, the drive motor starts, driving the worm gear shaft 3 to rotate. The first gear ring 11 meshes with the first meshing tooth 20, and the rack shaft 10 moves along its length, pushing the friction plates toward the steel plates through the thrust bearing 9 and the pressure plate 8 in sequence. At this time, the pressure plate 8 moves slowly, which helps to improve the smoothness of engagement. When the friction plates contact the steel plates and begin to transmit torque, the second gear ring 19 meshes with the second meshing tooth 21, and the pressure plate 8 quickly presses down, which helps to shorten the sliding friction time of the driving and driven parts and reduce the generation of frictional heat.

[0030] Analyzing the working process of this embodiment, a displacement-time curve of the pressure plate 8 during clutch engagement was obtained. In the segment from 0 to t1, the pressure plate 8 moves axially at a low speed v1, achieving low-speed contact between the friction plate and the steel plate. In the segment from t1 to t2, the pressure plate 8 moves at a higher speed v2, completing the clamping process. After complete clamping, the position of the pressure plate 8 remains constant, and the clutch remains engaged. This curve demonstrates the "slow at first, fast later" variable-speed engagement characteristic of this invention.

[0031] It should be noted that the lead angle, transmission ratio, and other parameters of the worm gear 4 are selected according to GB / T 10085-2018. By selecting a lead angle that enables self-locking, the worm gear 4 can achieve self-locking, maintaining the desired fixed state and clutch engagement without requiring additional power from the drive motor. Forward rotation of the drive motor engages the clutch; once engaged, power output stops, and the clutch remains engaged. To disengage the clutch, the drive motor is reversed, releasing the clutch.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An electric clutch actuator with a speed-changing engagement function, characterized in that, include: The worm gear (4) is rotatably mounted on the housing (5) of the actuator and is driven to rotate by the drive motor; The worm gear shaft (3) is coaxially connected to the worm gear (4). A first gear ring (11) and a second gear ring (19) are coaxially arranged on the worm gear shaft (3). The pitch circle radius of the first gear ring (11) is smaller than that of the second gear ring (19). The rack shaft (10) and the clutch have a pressure plate (8) for pushing the friction plate to engage with the steel plate. The rack shaft (10) is connected to the pressure plate (8). The rack shaft (10) is provided with a first meshing tooth (20) corresponding to the first gear ring (11) and a second meshing tooth (21) corresponding to the second gear ring (19). When the drive motor drives the worm gear (4) to rotate, the worm gear shaft (3) first connects with the first meshing tooth (20) through the first gear ring (11) to drive the pressure plate (8) to push the friction plate at a speed of v1. When the first gear ring (11) separates from the first meshing tooth (20), the friction plate and the steel plate are in contact. At this time, the second gear ring (19) connects with the second meshing tooth (21), and the drive pressure plate (8) pushes the friction plate and the steel plate to press together at a speed of v2, where v1 < v2.

2. The electric clutch actuator with speed-changing engagement function according to claim 1, characterized in that, Also includes: The worm is connected to the worm wheel (4) for transmission, and the worm is connected to the output end of the drive motor through the worm shaft (1).

3. The electric clutch actuator with speed-changing engagement function according to claim 1, characterized in that, The first gear ring (11) and the second gear ring (19) are arranged axially offset on the worm gear shaft (3).

4. An electric clutch actuator with a speed-changing engagement function according to claim 1, characterized in that, The first gear ring (11) has 20 teeth, the second gear ring (19) has 25 teeth, the first gear ring (11) and the second gear ring (19) both have a module of 10, and the pressure angle is 20°.

5. An electric clutch actuator with a speed-changing engagement function according to claim 1, characterized in that, The number of teeth in the first meshing tooth (20) and the second meshing tooth (21) does not exceed 3.

6. An electric clutch actuator with a speed-changing engagement function according to claim 2, characterized in that, A support bearing (2) is provided on the outer side of the worm shaft (1).

7. An electric clutch actuator with a speed-changing engagement function according to any one of claims 1-6, characterized in that, The clutch includes: Passive drum (13), the steel sheet is connected to the passive drum (13) by an external spline, and the passive drum (13) is connected to the passive shaft (7); The active drum (14) is connected to the friction plate via an internal spline. The active drum (14) is connected to the active shaft (6). The friction plate and the steel plate are arranged at intervals. The pressure plate (8) is coaxially disposed on the outside of the active drum (14), and a needle roller bearing (15) is disposed between the pressure plate (8) and the active drum (14). The inner side of the rack shaft (10) is connected to the active shaft (6) via a deep groove ball bearing (16), and the outer side is installed in a linear bearing (18). The linear bearing (18) is installed in the gearbox, and a thrust bearing (9) is disposed between the rack shaft (10) and the pressure plate (8).

8. An electric clutch actuator with a speed-changing engagement function according to claim 7, characterized in that, A first sleeve (17) is provided between the needle roller bearing (15) and the pressure plate (8), and a second sleeve (12) is provided between the deep groove ball bearing (16) and the rack shaft (10).

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