Rotary actuator

Abstract

To provide a rotary actuator capable of applying resistance force regardless of the direction of rotation when a rotating part rotates.SOLUTION: A rotary actuator 10 includes a motor; a worm gear that is connected to the motor and rotates in accordance with driving of the motor; a wheel having a wheel gear that is formed on an outer periphery and meshes with the worm gear, and a rotating portion that rotates integrally with the wheel gear; rotational resistance applying means that generates a resistance force against rotation of the rotating portion; and a fixed portion that rotatably supports the rotating portion and forms a space for holding the rotating portion and the rotational resistance applying means. The rotating portion has a connecting portion that is connected to an outer part and transmits torque from the motor to the outside. The wheel gear rotates in a forward direction or a reverse direction upon receiving torque from the worm gear, and the worm gear rotates in a forward direction or a reverse direction upon receiving torque from the wheel gear.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotary actuator that transmits torque generated by a motor to an external device. [Background technology]

[0002] Patent Document 1 discloses an electric locking device that locks the opening and closing mechanism of a glove box in a closed position relative to the opening. The electric locking device has a rod that engages and disengages with a locking section provided in the opening, and an actuator that slides the rod to disengage from the locking section. The actuator has a case, a motor, a wheel that is rotated by driving the motor, a rotor that engages with the wheel with a gap, and a torsion spring that biases the rotor in a direction to engage with the locking section. When a rotational force is applied from the rod to the rotor in a direction to release the locking section, the rotor and wheel disengage, and the rotor rotates independently of the wheel against the torsion spring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022-185890 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, when the wheel and rotor are disengaged, the torsion spring biases the rotor in only one direction, so no resistance is generated to the rotor's rotation in both directions. It would be desirable to be able to apply resistance to the rotor's rotation in both directions.

[0005] An object of the present invention is to provide a rotary actuator that can apply resistance force when a rotating part rotates, regardless of the direction of rotation. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention provides a rotary actuator comprising: a motor; a wheel having a worm gear connected to the motor and rotating in response to drive of the motor; a wheel gear formed on the outer periphery and meshing with the worm gear; a rotating part that rotates integrally with the wheel gear; rotational resistance applying means that generates resistance to rotation of the rotating part; a fixed part that rotatably supports the rotating part and forms a space to hold the rotating part and the rotational resistance applying means; and a connecting part that connects the rotating part to the outside and transmits torque from the motor to the outside. The wheel gear rotates forward or reverse in response to torque from the worm gear, and the worm gear rotates forward or reverse in response to torque from the wheel gear. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a rotary actuator that can apply resistance force regardless of the direction of rotation when the rotating part rotates. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a rotary actuator according to an embodiment. [Figure 2] FIG. 2 is an exploded view of the rotary actuator of the embodiment. [Figure 3] FIG. 2 is a perspective view of the rotary actuator with the second case removed. [Figure 4] FIG. 2 is a cross-sectional view of a rotary actuator. DETAILED DESCRIPTION OF THE INVENTION

[0009] Fig. 1 is a perspective view of a rotary actuator 10 according to an embodiment. Fig. 2 is an exploded view of the rotary actuator 10 according to an embodiment. Fig. 3 is a perspective view of the rotary actuator 10 with a second case 14 removed.

[0010] The rotary actuator 10 is used, for example, to open and close the lid of a glove box or console box in an automobile. An opening / closing body, which is a lid, is attached to an opening formed in a fixed body of the glove box or console box so that it can be opened and closed. The rotary actuator 10 is driven in response to the operation of an operation button, and rotates the opening / closing body in the opening and closing directions, automatically opening and closing the opening / closing body.

[0011] The rotary actuator 10 includes a first case 12 , a second case 14 , a gear unit 16 , a rotating unit 18 , a terminal unit 20 , a motor 22 , a worm gear 24 , a fixed unit 26 , a wheel 28 , a seal ring 30 and a viscous fluid 33 .

[0012] The first case 12 and the second case 14 are coupled to each other and house the internal components of the rotary actuator 10. The first case 12 is located on the lower side, and the second case 14 is located on the upper side. The motor 22 is driven in response to an operation by the occupant. The worm gear 24 is directly connected to the motor shaft and has teeth on its outer periphery. The worm gear 24 rotates in response to the driving of the motor 22 and transmits the torque generated by the driving of the motor 22 to the wheel 28. The terminal portion 20 is electrically connected to the motor 22 and has negative and positive conductive portions on its inside.

[0013] The first case 12 has a recess 34, a circumferential protrusion 35, a groove 36, a claw 37, a motor housing 38, a step 39, and a semi-cylindrical portion 40. As shown in FIG. 2, the recess 34 is formed as a cylindrical recess and supports the fixed portion 26. A plurality of grooves 36 are formed on the inner circumferential surface of the recess 34 and extend along the axial direction. The grooves 36 fit into the fixed portion 26 to prevent the fixed portion 26 from rotating.

[0014] The step 39 is formed above the recess 34 and has a larger diameter than the recess 34, forming a circumferential step. The circumferential protrusion 35 protrudes upward and is formed in the circumferential direction. A portion of the circumferential protrusion 35 is cut out by the groove 36. The step 39 and the circumferential protrusion 35 rotatably support the wheel 28.

[0015] A plurality of claws 37 are formed to protrude from the outer surface of the first case 12. The motor accommodating portion 38 forms a space that accommodates half of the motor 22. The semi-cylindrical portion 40 is connected to the motor accommodating portion 38 and forms an opening.

[0016] The second case 14 has an insertion tube portion 42, an upper housing portion 44, a motor housing portion 46, a semi-cylindrical portion 48, and an elastic locking portion 49. The insertion tube portion 42 is formed in a cylindrical shape and opens upward, allowing a portion of the rotating portion 18 to be inserted therein. The upper housing portion 44, when coupled with the first case 12, forms a space to house the rotating portion 18, the fixed portion 26, and the wheel 28.

[0017] Motor accommodating portion 46 mates with motor accommodating portion 38 to form a space for accommodating motor 22. Half-cylinder portion 48 mates with half-cylinder portion 40 to form an opening for inserting terminal portion 20. Elastic locking portion 49 engages with claw portion 37 of first case 12 to join first case 12 and second case 14 together. The joined first case 12 and second case 14 is simply referred to as the case.

[0018] The gear unit 16 is connected to an external component to transmit torque. Here, the external component may be, for example, a gear on the opening / closing body. The gear unit 16 rotates in response to the opening and closing operation of the opening / closing body. The gear unit 16 has a rectangular connecting hole 16a.

[0019] The rotating part 18 and the fixed part 26 are connected to form an oil damper. Now, a detailed description will be given with reference to a new drawing. Figure 4 is a cross-sectional view of the rotary actuator 10.

[0020] The fixing part 26 has an outer tube part 60, a fitting part 61, a columnar part 62, and an inner tube part 64. The outer tube part 60 is formed in a cylindrical shape. The fitting parts 61 are formed to protrude from the lower part of the outer peripheral surface of the outer tube part 60, and multiple fitting parts 61 are formed at intervals in the circumferential direction. The lower part of the outer tube part 60 is inserted into the recessed part 34 of the first case 12, and the fitting parts 61 enter and fit into the groove part 36 of the first case 12. In this way, the fixing part 26 is fixed to the first case 12.

[0021] The inner cylinder portion 64 is formed inside the outer cylinder portion 60 and is cylindrical with a smaller diameter than the outer cylinder portion 60. The inner cylinder portion 64 may have a plurality of through holes formed therein as paths for the viscous fluid 33 to travel. The columnar portion 62 is formed inside the inner cylinder portion 64 and has a smaller diameter than the inner cylinder portion 64. The outer cylinder portion 60 and the inner cylinder portion 64 open upward. The axial height of the inner cylinder portion 64 is lower than those of the outer cylinder portion 60 and the columnar portion 62. The axial height of the columnar portion 62 is lower than that of the outer cylinder portion 60.

[0022] The rotating part 18 rotates integrally with the wheel 28. The rotating part 18 has a first cylindrical part 50, a plate part 51, a pillar part 52, a protrusion part 53, a connecting part 54, and a second cylindrical part 56. The first cylindrical part 50 is formed in a cylindrical shape and opens downward. The plate part 51 is located at the upper end of the first cylindrical part 50 and is formed in a disk shape. The second cylindrical part 56 is formed in a cylindrical shape with a smaller diameter than the first cylindrical part 50. The first cylindrical part 50 and the second cylindrical part 56 are formed with a through hole 50a and a through hole 56b as a flow path for the viscous fluid 33. Forming the rotating part 18 and the wheel 28 separately makes it easier to mold the rotating part 18, and also makes it easier to mold the through hole 50a of the first cylindrical part 50 and the through hole 56b of the second cylindrical part 56.

[0023] As shown in FIG. 2 , the pillar portion 52 stands upright from the plate portion 51 and has a cross-shaped cross section. A pair of protrusions 53 are formed protruding from the plate portion 51 and protrude radially outward from the columnar portion 62. The connecting portion 54 is located on the tip side of the pillar portion 52 and is formed in a rectangular column shape. The pillar portion 52 and the connecting portion 54 are inserted into the insertion tube portion 42 of the second case 14. The connecting portion 54 is inserted into the connecting hole 16a of the gear portion 16 to connect to the gear portion 16 and transmit torque from the motor 22 to the gear portion 16.

[0024] The annular protrusion 55 is formed to protrude from the outer peripheral surface of the first cylindrical portion 50, and is located at the top of the first cylindrical portion 50. As shown in FIG. 4, the annular protrusion 55 engages with the inner surface of the outer cylindrical portion 60 of the fixing part 26. The circumferential groove 57 is formed to be recessed in the circumferential direction on the outer peripheral surface of the first cylindrical portion 50, and is located below the annular protrusion 55. The seal ring 30 is fitted in the circumferential groove 57. The seal ring 30 may be an O-ring.

[0025] The connection between the rotating part 18 and the fixed part 26 will now be described. A viscous fluid 33 is filled inside at least one of the rotating part 18 and the fixed part 26, and the rotating part 18 is inserted into the fixed part 26. The viscous fluid 33 may be oil such as grease. The annular protrusion 55 of the rotating part 18 engages with the outer cylindrical part 60 of the fixed part 26, thereby rotatably connecting the rotating part 18 and the fixed part 26. The fixed part 26 supports the rotating part 18 so that it can rotate.

[0026] At this time, a filling space that holds the viscous fluid 33 is formed between the rotating part 18 and the fixed part 26. The filling space is sealed by the seal ring 30. The filling space is formed by the outer cylindrical part 60, the inner cylindrical part 64, the cylindrical part 62, and the first cylindrical part 50 and the second cylindrical part 56 that are inserted into the space formed by them.

[0027] Because the filling space is configured in multiple layers inside the rotating part 18 and the fixed part 26, the contact area of ​​the viscous fluid 33 increases, and the shear force can be increased. When the rotating part 18 rotates with respect to the fixed part 26, the rotating part 18 and the fixed part 26 rotate relative to each other, and the viscous fluid 33 exerts a shear force, which is a resistance force that resists the relative rotation. The viscous fluid 33 functions as a rotation resistance imparting means that imparts resistance to the relative rotation of the rotating part 18 and the fixed part 26. The viscous fluid 33 is interposed between the wheel 28 and the fixed part 26, more specifically, between the rotating part 18 and the fixed part 26.

[0028] The wheel 28 has a protruding portion 70, a cylindrical portion 71, a central hole 72, and a wheel gear 74. The protruding portion 70 protrudes radially inward from the periphery of the upper end of the cylindrical portion 71, forming the central hole 72. The central hole 72 has a pair of notches 72a cut out radially outward. The protrusion 53 of the rotating portion 18 fits into the inner surface of the central hole 72, particularly the notches 72a, causing the rotating portion 18 and the wheel gear 74 to rotate together. The protruding portion 70 also limits the axial movement of the rotating portion 18. In other words, the protruding portion 70 both allows the rotating portion 18 to rotate together with the wheel gear 74 by fitting the rotating portion 18 in place and limits the axial movement of the rotating portion 18. This ensures space inside the wheel gear 74, allowing the rotating portion 18 and the fixed portion 26 to use that space.

[0029] The wheel gear 74 is formed on the outer periphery of the wheel 28 and meshes with the worm gear 24. The wheel gear 74 is formed circumferentially on the outer periphery of the cylindrical portion 71. As shown in FIG. 4 , the cylindrical portion 71 has a longer axial length than the wheel gear 74 and protrudes above and below the wheel gear 74.

[0030] In the embodiment, the rotating part 18 and the wheel 28 are formed separately, but the present invention is not limited to this and they may be formed integrally. In either case, the rotating part 18 is connected to the wheel 28 and rotates integrally with the wheel gear 74.

[0031] As shown in FIG. 4 , the second case 14 has a first limiting portion 43 and a second limiting portion 47. The first limiting portion 43 hangs down from the ceiling surface of the second case 14 and abuts or is close to the upper surface of the protruding portion 70, limiting the axial movement of the wheel gear 74. The first limiting portion 43 may be formed in a cylindrical shape or may be a plurality of protrusions. This prevents the wheel gear 74 from disengaging from the rotating portion 18 and prevents the fitting portion 61 of the fixed portion 26 from disengaging from the groove portion 36 of the first case 12.

[0032] The second limiting portion 47 hangs down from the ceiling surface of the second case 14 and abuts against or is close to the outer circumferential surface of the cylindrical portion 71, restricting the radial movement of the wheel gear 74. The second limiting portion 47 may be formed in a cylindrical shape with a larger diameter than the first limiting portion 43. The second limiting portion 47 is formed so as to surround the outer periphery of the cylindrical portion 71. Because the rotating portion 18 and the wheel gear 74 are in a state of being floated from the fixed portion 26 via the viscous fluid 33, the second limiting portion 47 suppresses axial wobble.

[0033] The operation of the rotary actuator 10 will now be described. The motor 22 is driven by a user's operation signal, and rotates the motor shaft forward or backward according to the operation signal. The worm gear 24 is connected to the motor shaft and rotates forward or backward together with the motor shaft, i.e., in either direction. Forward rotation of the motor shaft acts in the direction to open the opening / closing body, and reverse rotation acts in the direction to close the opening / closing body.

[0034] The torque of the worm gear 24 is transmitted to the wheel 28, causing the wheel 28 to rotate forward or backward around its axis. The rotating part 18 rotates integrally with the wheel 28 and rotates relative to the fixed part 26. In other words, the wheel gear 74 and the rotating part 18 receive torque from the worm gear 24 and rotate forward or backward. When the rotating part 18 rotates relative to the fixed part 26, the viscous fluid 33 generates a resistance force, and the rotating part 18 and the fixed part 26 function as a damper. This allows the speed of the motor 22 to be adjusted using the damper function.

[0035] Next, we will explain the operation when the user opens and closes the opening / closing body. When the user opens or closes the opening / closing body, the torque of the opening / closing operation is transmitted from the gear unit 16 to the connecting unit 54 of the rotating unit 18, causing the rotating unit 18 to rotate forward or backward. The rotating unit 18 rotates together with the wheel 28, and the worm gear 24 receives torque from the wheel gear 74 and rotates forward or backward. In addition, the rotating unit 18 rotates relative to the fixed unit 26, and the viscous fluid 33 generates a resistance force.

[0036] The wheel gear 74 and the worm gear 24 rotate together due to torque from the motor 22 side, and also rotate together due to torque from the gear unit 16 in the opposite direction. Furthermore, because the wheel gear 74 and the worm gear 24 can transmit torque in either forward or reverse rotation to each other, the rotary actuator 10 can function as a damper regardless of whether the rotation is forward or reverse. The viscous fluid 33 generates resistance between the rotating unit 18 and the fixed unit 26, making it possible to stop the opening / closing body at any rotational position.

[0037] 3 and 4, the damping functions of the rotating portion 18 and the fixed portion 26 are disposed radially inside the wheel gear 74. By accommodating the damping function configuration inside the wheel gear 74, the axial length of the rotary actuator 10 can be reduced, and the rotary actuator 10 can be made more compact.

[0038] Since the gear unit 16 is directly connected to the rotating unit 18, the resistance force of the viscous fluid 33 acting on the rotating unit 18 acts directly on the gear unit 16. This makes it easy to adjust the torque and allows the resistance force to always act on the gear unit 16.

[0039] The viscous resistance of the viscous fluid 33 is set to 40 percent or less of the stall torque of the motor 22. When the user opens or closes the opening / closing body, the viscous fluid 33 provides an appropriate resistance, resulting in a good operational feel. The resistance force of the viscous fluid 33 decreases at high temperatures and increases at low temperatures in accordance with the temperature characteristics of the motor 22. This changes the resistance force of the damper in accordance with the temperature characteristics of the motor 22, minimizing changes due to environmental temperature.

[0040] The present invention is not limited to the above-described embodiments, and various modifications such as design changes may be made to the embodiments based on the knowledge of those skilled in the art, and such modified embodiments may also be included within the scope of the present invention.

[0041] For example, although the embodiment has been described in which the rotating portion 18 and the fixed portion 26 are formed in two layers, the present invention is not limited to this. Depending on the viscosity of the viscous fluid and the size of the rotary actuator 10, the rotating portion 18 and the fixed portion 26 may be formed in one layer or three layers.

[0042] In addition, although the embodiment shows an embodiment in which the rotational resistance imparting means is a viscous fluid such as oil, this is not limiting. For example, the rotational resistance imparting means may be an elastic member such as rubber or a torsion spring. In either case, the rotational resistance imparting means generates resistance to the relative rotation between the rotating part 18 and the fixed part 26.

[0043] In addition, although the embodiment has been described in which the first case 12 and the fixed portion 26 are separate bodies, this is not limiting. For example, the first case 12 and the fixed portion 26 may be integrally formed. In either case, the first case 12 supports the fixed portion 26 so that it does not rotate. [Explanation of symbols]

[0044] 10 rotary actuator, 12 first case, 14 second case, 16 gear portion, 18 rotating portion, 20 terminal portion, 22 motor, 24 worm gear, 26 fixed portion, 28 wheel, 30 seal ring, 33 viscous fluid, 34 recessed portion, 35 circumferential convex portion, 36 groove portion, 37 claw portion, 38 motor accommodating portion, 39 stepped portion, 40 semi-cylindrical portion, 42 insertion cylindrical portion, 43 first limiting portion, 44 upper accommodating portion, 46 motor accommodating portion, 47 second limiting portion, 48 semi-cylindrical portion, 49 elastic locking portion, 50 first cylindrical portion, 51 plate portion, 52 column portion, 53 protrusion portion, 54 connecting portion, 55 annular convex portion, 56 Second cylindrical portion, 57 circumferential groove portion, 60 outer cylindrical portion, 61 fitting portion, 62 cylindrical portion, 64 inner cylindrical portion, 70 protruding portion, 71 cylindrical portion, 72 central hole, 74 wheel gear.

Claims

1. A motor; a worm gear connected to the motor and rotating in response to the driving of the motor; a wheel having a wheel gear formed on its outer periphery and meshing with the worm gear, and a rotating portion that rotates integrally with the wheel gear; a rotation resistance applying means for applying a resistance force to the rotation of the rotating portion; a fixed portion that rotatably supports the rotating portion and forms a space for holding the rotating portion and the rotation resistance applying means; the rotating part has a connecting part that is connected to an external part and transmits torque from the motor to the external part, The wheel gear receives torque from the worm gear and rotates forward or backward, The rotary actuator is characterized in that the worm gear receives torque from the wheel gear and rotates forward or backward.

2. The wheel has a protruding portion that protrudes radially inward from a periphery and defines a central hole; the rotating portion is provided separately from the wheel gear, is fitted to the inner surface of the central hole, and rotates integrally with the wheel gear; The rotary actuator according to claim 1 , wherein the protrusion limits axial movement of the rotating part.

3. 3. The rotary actuator according to claim 1, further comprising a gear portion connected to the connecting portion.

4. a case formed integrally with or separately from the fixing portion, and supporting the fixing portion so as to prevent it from rotating; The case is a first limiting portion that limits axial movement of the wheel gear; 3. The rotary actuator according to claim 1, further comprising: a second limiting portion that limits radial movement of the wheel gear.

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