Power transmission device

Abstract

A clutch mechanism for controlling a power transmission device for driving a vehicle by a motor, characterized by comprising: a clutch member capable of moving in both directions in an axial direction; a base member prevented from rotating around a shaft; a counterweight member opposed to the base member in the axial direction and restricted from moving in a circumferential direction and the axial direction; a motion member interposed between the base member and the counterweight member, capable of moving in the axial direction and drivingly coupled to the clutch member, and coupled to the motor to generate a rotational motion around the shaft; and a cam inclined from the base member toward the counterweight member in the circumferential direction and guiding the motion member in order to convert the rotational motion into a motion in the axial direction of the motion member.

Description

Technical Field

[0001] The following disclosure relates to a clutch mechanism that uses a motor to control the power transmission device that drives a vehicle, and more particularly to a clutch mechanism that can operate the clutch components bidirectionally according to the rotation angle of the motor. Background Technology

[0002] Vehicles often utilize clutches to selectively operate and stop rotating machinery. For example, a locking differential incorporates a claw clutch, which normally disengages to allow differential movement between the output shafts, but locks the differential when engaged by an external actuator.

[0003] Clutches are built into rotating machinery, and special mechanisms are required to operate them from the stationary side, i.e., externally. To date, actuators utilizing cam mechanisms of motors, solenoid actuators, etc., have been proposed. Related technologies are disclosed in Patent Documents 1 to 3.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Patent Application Publication WO2017 / 060963A1

[0007] Patent Document 2: International Patent Application Publication WO2016 / 035129A1

[0008] Patent Document 3: International Patent Application Publication WO2018 / 109874A1 Summary of the Invention

[0009] While conventional actuators offer many advantages, they suffer from a problem where their operation doesn't necessarily correspond to the clutch's state. Specifically, even when power is applied to the motor or solenoid, lag exists in the cam mechanism. Furthermore, under less frequent conditions, such as occasional improper meshing of the clutch teeth, the clutch may engage and be damaged. Additionally, even when power is cut off, the clutch teeth may temporarily stick together due to the viscosity or magnetization of the lubricating oil, delaying disengagement. Therefore, to prevent accidental operation, additional devices for detecting clutch engagement are often required.

[0010] The device disclosed below is designed in view of the above-mentioned problems. The rotation angle of the motor accurately reflects the travel length of the clutch components, so that it is possible to determine whether the clutch is engaged or disengaged simply by measuring the rotation angle.

[0011] According to one aspect, a clutch mechanism is provided for a power transmission device that uses a motor to control a vehicle, characterized by comprising: a clutch component capable of bidirectional axial movement; a base member prevented from rotating about an axis; a counterweight member axially separated from the base member and restricted in circumferential and axial movement; an actuating member located between the base member and the counterweight member, capable of axial movement and drivably engaged with the clutch component, and engaged with the motor to generate rotational motion about the axis; and a cam ramp inclined along the circumferential direction from the base member toward the counterweight member and guiding the actuating member in order to convert the rotational motion into axial motion of the actuating member. Attached Figure Description

[0012] Figure 1 This is a partial cross-sectional elevation view of a differential device including a clutch mechanism according to one embodiment.

[0013] Figure 2 This is a partial cross-sectional elevation view of a differential device including a clutch mechanism according to other embodiments.

[0014] Figure 3A It is an exploded 3D view of the motor and clutch mechanism.

[0015] Figure 3B Is with Figure 3A The exploded front view of the corresponding clutch mechanism.

[0016] Figure 4A It is a detailed sectional elevation view of the motor and clutch mechanism.

[0017] Figure 4B Based on other examples and Figure 4A The corresponding partial sectional elevation view.

[0018] Figure 4C This is based on another example and Figure 4A The corresponding partial sectional elevation view.

[0019] Figure 5 This is a circumferential cross-sectional view illustrating the movement of the actuators in a clutch mechanism. Detailed Implementation

[0020] Hereinafter, several exemplary embodiments will be described with reference to the accompanying drawings. In the following description and claims, unless otherwise specified, the shaft refers to the central shaft of the clutch mechanism, and is generally also consistent with the rotational shaft of the power transmission device. It should be noted that the drawings are not necessarily shown at an exact scale, and therefore the dimensional relationships are not limited to those shown in the figures.

[0021] The clutch mechanism and motor combination disclosed below can be appropriately combined with rotating machinery such as differentials to form a power transmission device for driving vehicles. In particular, it can be used to control the function of the clutch by engaging and disengaging it from outside the rotating machinery. It should be understood from the following description that the motor can be rotated forward or reversed to engage or disengage the clutch, and during this process, the rotation angle of the motor always accurately reflects the position of the clutch components.

[0022] The embodiments described below relate to a differential, or can be applied to other rotating machinery such as transmissions, power transmission units (PTUs), and coupling devices. Furthermore, the clutch is, for example, a so-called claw clutch with claw-shaped teeth, but it can generally be used in other forms of clutches, such as closed clutches, which more generally transmit torque through a meshing structure rather than friction, or in friction clutches such as multi-plate clutches.

[0023] Main reference Figure 1 , Figure 2 The clutch mechanism 1 is combined with the motor 5 to drive the clutch 7 in order to control the operation of the differential 3.

[0024] The differential 3 receives torque from the engine, for example, via a gear ring fixed to a flange extending radially from its housing 31, and rotates about axis X as indicated by arrow T. In the illustrated example, the differential 3 has a bevel gear type differential gear set, with pinion 33 rotatably supported on housing 31, and differentially distributing torque to the two axles through engagement with a pair of side gears 35, 37. Differential movement between side gears 35, 37 is permitted when clutch 7 is disengaged, but is locked when engaged. Of course, other forms such as planar gears or planetary gears can be used instead of bevel gears. Figure 1 , Figure 2 The example shown involves a so-called locking differential, but it can also be replaced by a clutch mechanism 1 combined with a so-called free-running differential.

[0025] The housing 31 can be a two-piece design that can be divided into at least two parts, or it can be a single-piece design that is not divided. In the two-piece design, the housing is divided, for example, on the flange side. Regardless of the type, the clutch mechanism 1, the motor 5, and the clutch 7 can all be configured as follows: Figure 1 As shown, if positioned on the side opposite to the flange, it can also be like... Figure 2 It is configured on the flange side as shown.

[0026] Reference Figure 3A , Figure 3BThe clutch mechanism 1 generally consists of a base member 13, a counterweight member 15 that is axially separated and opposed to it, and an actuating member 11 sandwiched between them. The actuating member 11, the base member 13, and the counterweight member 15 are annular sheet metal about axis X and have several axially projecting structures. While they do not necessarily have to be annular and made of sheet metal, these elements are advantageous in that they can be easily manufactured by punching, cutting, or stamping sheet metal, for example, made of steel for mechanisms. These components are adjacent to but disposed outside the housing 31 and share axis X with the housing 31.

[0027] The base member 13 is anti-rotational relative to the vehicle body, particularly relative to, for example, a bracket. The counterweight member 15 engages with the base member 13, thereby restricting or fixing its movement in both the axial and circumferential directions. The actuating member 15 is clamped between them and is able to move axially and circumferentially. To return the actuating member 15 to its initial position, a spring 25, for example, pressing the actuating member 15 toward the base member 13, can be clamped between the counterweight member 15 and the actuating member 11.

[0028] The actuating member 11 has gear teeth 11G for meshing with the gear of the motor 5. For example, the outer periphery of the actuating member 11 may partially protrude radially outward, with gear teeth 11G etched on its outer periphery. This is a preferable configuration for positioning the motor 5 radially outward from the clutch mechanism 1, so that the gear shaft 15G meshes with the clutch mechanism 1. If possible, the gear teeth 11G may also be etched in other locations to position the motor 5 elsewhere. Figure 3A , Figure 3B Combined reference Figure 4A The actuating component 11 receives the rotation of the motor 5 through the meshing of gear teeth 11G and gear shaft 15G, thereby generating rotational motion around axis X. Of course, both forward and reverse rotation are possible.

[0029] Motor 5 can be like Figure 4A The rotor's rotation can be output directly to the gear shaft 15G as illustrated, but it can also be constructed via a gear mechanism. For example, Figure 4B This is an example of motor 5 outputting rotation via worm gear mechanism 41. When worm gear mechanism 41 is present, the position of gear teeth 11G is maintained because its own gear resistance resists external forces. Alternatively, instead of motor 5 having worm gear mechanism 41, a worm gear assembly can be formed by gear shaft 15G and gear teeth 11G. In either case, it is not necessary to continuously supply power to motor 5 to maintain the position of the actuating member 11, so this structure is beneficial for energy saving.

[0030] Or, such as Figure 4CAs illustrated, the engagement of motor 5 and actuating member 11 can also be independent of gear teeth 11G. If motor 5 is an axial or radial clearance motor with a hollow shaft rotor 51, motor 5 can also be coaxial with differential 3 and clutch mechanism 1. The engagement of rotor 51 and actuating member 11 can also be via a rotating member 53 splined with rotor 51. The rotating member 53 is, for example, a generally cylindrical shape with keyways on its outer surface for splined engagement with rotor 51, and also has flanges for bolting, but its shape is not necessarily limited to this. The rotating member 53 can also replace the fixing plate 19 described later for fixing ball bearing 21. Alternatively, actuating member 11 and rotating member 53 can be integral.

[0031] In addition, the motor 5 needs to be stopped from rotating, which can be achieved, for example, by a bracket 43 fixed to the bracket. The stopping of the base member 13 can also be achieved by the bracket 43, or the base member 13 and the bracket 43 can be integrated.

[0032] Return to reference Figure 3A , 3B The clutch component 9 is located at the far end of the clutch mechanism 1, typically within the housing 31. The clutch component 9 has an engagement structure on its end face, similar to clutch teeth 9T. In the case of a locking differential, one side gear 35 has a corresponding engagement structure, which, combined with the clutch component 9, constitutes the clutch 7. As described above, in the case of a free-running differential, the inner housing has an engagement structure that constitutes the clutch 7. The clutch component 9 can move axially in both directions within the housing 31; when it moves away from the side gear 35 (or the inner housing), the clutch 7 disengages, and when it moves in the opposite direction, the clutch 7 engages. Although not strictly necessary, a return spring 27 can be used to facilitate disengagement of the clutch 7.

[0033] The actuating member 11 can be directly engaged with the clutch assembly 9, but a transfer member 17 can also be sandwiched between them to transmit its axial movement to the clutch assembly 9. The engagement of the clutch assembly 9 and the transfer member 17 can be, for example, by bolts, utilizing one or both of a leg 9L extending from the clutch assembly 9 and a protrusion 17T extending from the actuating member 11 for bolt engagement. For example, as... Figure 1 As shown, the tab 17T can also be exposed externally through a large opening 31H at the end of the housing 31, where it can be bolted together. Alternatively, as... Figure 2As illustrated, opening 31H is an extremely fine through hole through which the tab 17T can also be inserted into housing 31 and engage with the internal clutch component 9. As will be described in detail later, in any case, opening 31H does not need to have a cam structure for assisting the engagement of clutch component 9; this is easy to manufacture and does not compromise the strength and rigidity of housing 31. If it is as follows... Figure 2 Such fine through holes are more conducive to maintaining strength and rigidity.

[0034] Return to reference Figure 3A , Figure 3B The transfer member 17 and the actuating member 11 are coupled, for example, via a ball bearing 21, thereby allowing the transfer member 17 to rotate relative to the actuating member 11. Other types of bearings may be used instead of the ball bearing 21, or the actuating member 11 may be coupled to the transfer member 17 in a slidable manner, provided smooth rotation is ensured. In the case of the ball bearing 21, the inner circumference of the actuating member 11 may have a structure suitable for its insertion and interlocking. Furthermore, for example, a fixing plate 19 may be used to clamp the ball bearing 21 between the fixing plate 19 and the actuating member 11, allowing them to move axially as a single unit. The ball bearing 21 is fixed to the transfer member 17, and for this fixation, a retaining ring 23 may be used, for example. Thus, the transfer member 17 can rotate relative to the actuating member 11, while the bidirectional axial movement of the actuating member 11 is transmitted to the clutch assembly 9.

[0035] and Figure 3A , Figure 3B Combined reference Figure 5 The combination of components 11, 13, and 15 has a structure for converting the rotational motion of the actuating member 11, which is driven by the motor 5, into axial motion. One example is a cam inclined surface 13C that slopes from the base member 13 toward the counterweight member 15. When the actuating member 11 produces a circumferential rotational motion R, the cam inclined surface 13C guides the actuating member 11 to produce an axial motion M. As described above, this structure can be easily formed by stamping. Alternatively, although not shown, the cam inclined surface 13C can also be separate from the base member 13.

[0036] The actuating member 11 has a structure associated with the cam ramp 13C, one example being a ramp 11C corresponding to the cam ramp 13C. More preferably, this ramp 11C has a dimension that is always in contact with the cam ramp 13C. Moreover, correspondingly, the counterweight member 15 can also have a second cam ramp 15C. The ramp 11C of the actuating member 11 always maintains contact with both the cam ramps 13C and 15C while moving. This prevents lag in the axial movement M relative to the rotational movement R. That is, the rotation angle of the motor 5 accurately reflects the axial movement of the clutch component 9.

[0037] As a component of the actuating member 11 associated with the cam ramp 13C, an opening for receiving the cam ramp 13C may be used instead of the ramp 11C. The cam ramp 13C is partially embedded in the opening in the actuating member 11, guiding the actuating member 11 through sliding contact. In this case, the second cam ramp 15C may also be... Figure 5 Conversely, the inclined surfaces 11C and 15C, which slope towards the base member 13, always remain in contact with and guide the actuating member 11. This configuration not only converts the rotational motion R into the axial motion M but also prevents hysteresis.

[0038] As understood from the description so far, if the motor 5 causes the actuating member 11 to rotate about axis X, the actuating member 11 moves axially in response to the rotation, driving the clutch component 9. The rotation angle of the rotor of the motor 5 corresponds one-to-one with the axial movement length of the clutch component 9, so it is possible to determine whether the clutch 7 is engaged or disengaged simply by detecting the rotation angle. Furthermore, the rotation angle can be detected, for example, by reading the change in the motor's inductance, or electrically if an encoder is mounted on the rotor. No additional device is needed to determine whether the clutch is engaged or disengaged. Moreover, even if an external force is applied to the clutch component 9, the cam structure provides sufficient resistance. That is, no special structure is needed to maintain the engagement of the clutch 7. This simplifies the manufacture of the housing 31 without sacrificing its strength and rigidity.

[0039] Several implementation methods have been described, but modifications or variations can be made to the implementation methods based on the above disclosure.

Claims

1. A clutch mechanism that uses a motor to control the power transmission device driving a vehicle, characterized in that, have: A clutch component that is capable of bidirectional axial movement; The base component is prevented from rotating about its axis; A counterweight component, which is axially separated from the base component and is restricted from moving in both the circumferential and axial directions; An actuating component, located between the base component and the counterweight component, is axially movable and drivably engaged with the clutch component, and is engaged with the motor to generate rotational motion about the axis; as well as The cam ramp, which in order to convert the rotational motion into axial motion of the actuating member, is inclined circumferentially from the base member toward the counterweight member and guides the actuating member.

2. The clutch mechanism according to claim 1, characterized in that, It also includes a spring located between the counterweight member and the actuating member, which presses the actuating member toward the base member.

3. The clutch mechanism according to claim 1, characterized in that, The cam ramp surface is integral with the base component.

4. The clutch mechanism according to claim 1, characterized in that, It also includes a transfer member that engages with the actuating member and the clutch assembly and transmits the axial motion to the clutch assembly.

5. The clutch mechanism according to claim 1, characterized in that, The counterweight component integrally has a second cam inclined surface that contacts and guides the actuating component.

6. The clutch mechanism according to claim 5, characterized in that, The actuating component has an inclined surface that makes surface contact with both the cam inclined surface and the second cam inclined surface.

7. The clutch mechanism according to claim 1, characterized in that, The actuating member has a gear that meshes with the motor gear, or a rotating member that engages with the rotor spline of the motor, thereby being driven by the motor to generate the rotational motion.

8. A power transmission device, characterized in that, have: The clutch mechanism as claimed in claim 1; and A differential gear set, which has a pair of side gears that differentially output torque. The inner housing of one of the pair of side gears or the differential gear set has clutch teeth that mesh with the clutch component and together with the clutch component constitutes a clutch.

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