Hydraulic actuator using hollow motor

Abstract

The present invention discloses a hydraulic actuator using a hollow motor that enables pressurization of a fluid through the axial movement of a spindle, which is achieved by the rotation of a nut body linked to the rotation of the motor. A hydraulic actuator using the aforementioned hollow motor comprises a cylinder body forming a pressure chamber, a housing coupled to the cylinder body, a hollow motor installed inside the housing, a nut body coupled to the rotor of the hollow motor in a rotational direction, a spindle coupled to the nut body and coupled in an axial direction, and a piston coupled in an axial direction inside the pressure chamber according to the axial movement of the spindle.

Description

Technology Field

[0001] The present invention relates to a hydraulic actuator using a hollow motor, and more specifically, to a hydraulic actuator using a hollow motor that enables pressurization of a fluid through the axial movement of a spindle achieved by the rotation of a nut body linked to the rotation of the motor. Background Technology

[0002] In general, in vehicles equipped with Automated Manual Transmission (AMT) and Double Clutch Transmission (DCT), the driving force generated from a power source such as an engine and supplied to the transmission is intermittently produced by the operation of the clutch, and this operation of the clutch is mainly implemented by a hydraulic actuator.

[0003] In addition, the operation of the control mechanism for shifting in semi-automatic manual transmissions and double-clutch transmissions is also primarily implemented by hydraulic actuators.

[0004] Conventionally, hydraulic actuators that utilize hydraulic pressure generated by the driving of a motor have a motor and a piston for generating hydraulic pressure that are not arranged coaxially, so the radial volume of the actuator is inevitably large, and consequently, the radial space occupied by the hydraulic actuator becomes excessively large, causing a problem in which interference with surrounding parts must be considered in the design of the product.

[0005] In addition, conventional hydraulic actuators cause a problem where the working fluid leaks to the outside due to insufficient airtightness of the piston operating inside the pressure chamber in response to the motor's drive. Prior art literature

[0006] Registered Patent No. 10-1206452 The problem to be solved

[0007] The technical problem that the present invention aims to solve is to provide a hydraulic actuator using a hollow motor that enables pressurization of a fluid through the axial movement of a spindle, which is achieved by the rotation of a nut body linked to the rotation of the motor. means of solving the problem

[0008] An embodiment of the present invention for solving the above-mentioned technical problem preferably comprises a cylinder body forming a pressure chamber, a housing coupled to the cylinder body, a hollow motor installed inside the housing, a nut body installed to move in rotational direction with the rotor of the hollow motor, a spindle installed to move in axial direction by being meshed with the nut body, and a piston installed to move in axial direction inside the pressure chamber according to the axial movement of the spindle.

[0009] In a preferred embodiment of the present invention, the rotor and the nut body are preferably coupled so as to be mutually constrained along the direction of rotation.

[0010] In a preferred embodiment of the present invention, it is preferable that the inner surface of the rotor and the outer surface of the nut body be configured to be spline-coupled or key-coupled so as to be constrained in the rotational direction.

[0011] In a preferred embodiment of the present invention, the piston comprises a shaft portion extending along the axial direction of the pressure chamber and a plurality of skirt portions arranged along the longitudinal direction of the shaft portion, and it is preferable that a sealing member in close contact with the inner surface of the pressure chamber is installed between the plurality of skirt portions.

[0012] In a preferred embodiment of the present invention, the sealing member preferably comprises a hollow boss portion mounted on the shaft portion and a lip portion extending radially outward from the boss portion and in close contact with the inner surface of the pressure chamber.

[0013] A preferred embodiment of the present invention preferably comprises a fixed radial bearing that supports the nut body in a rotational direction within the housing, a thrust bearing that supports the nut body in an axial direction within the housing, and a movable radial bearing installed between the spindle and the piston to support the relative rotation of the spindle with respect to the piston.

[0014] In a preferred embodiment of the present invention, the fixed radial bearing is preferably installed to rotatably support both ends of the nut body inside the cylinder body and inside the housing.

[0015] In a preferred embodiment of the present invention, the thrust bearing is preferably installed between the free end of the nut body and the housing and configured to rotatably support the free end of the nut body axially with respect to the housing.

[0016] In a preferred embodiment of the present invention, the piston preferably has a locking end for mounting the outer ring of the movable radial bearing, and the spindle preferably has a seating end for mounting the inner ring of the movable radial bearing.

[0017] In a preferred embodiment of the present invention, the cylinder body preferably has a snap ring fastened to an inner circumference for axial fixation of the fixed radial bearing.

[0018] A preferred embodiment of the present invention is preferably configured to further include an O-ring installed to maintain airtightness between the cylinder body and the housing.

[0019] A preferred embodiment of the present invention is preferably configured to further include a dowel pin installed for provisional fastening between the cylinder body and the housing. Effects of the invention

[0020] In the hydraulic actuator according to an embodiment of the present invention, rotation of the nut body in an interlocking manner can be achieved in accordance with the rotation of the hollow motor, and since pressurization of the fluid stored inside the pressure chamber can be achieved by the piston moving axially inside the pressure chamber of the cylinder body through the axial movement of the spindle achieved by the rotation of the nut body, operation of external devices by the pressure of the compressed fluid can be realized.

[0021] At this time, the hydraulic actuator according to an embodiment of the present invention can provide a motor-driven hydraulic actuator by applying a ball screw type assembly structure between a nut body that operates in a rotational direction accompanying the operation of a hollow motor and a spindle that operates in an axial direction.

[0022] In addition, the hydraulic actuator according to the embodiment of the present invention allows the hollow motor and the nut body to be arranged concentrically with respect to the axial center of the spindle through a spline coupling or key coupling between the rotor of the hollow motor and the nut body. This enables not only a reduction in the radial package of the hydraulic actuator but also the prevention of leakage into the pressure chamber of the cylinder body and the smooth generation of hydraulic pressure through a multi-structured sealing member applied to the piston. Brief explanation of the drawing

[0023] FIG. 1 is a front view illustrating a hydraulic actuator using a hollow motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, illustrating the internal configuration of a hydraulic actuator using a hollow motor according to an embodiment of the present invention. FIG. 3 is an exploded perspective view showing the cylinder body disassembled in a hydraulic actuator using a hollow motor according to an embodiment of the present invention. FIG. 4 is an exploded perspective view showing the cylinder body, housing, and lower cover each disassembled in a hydraulic actuator using a hollow motor according to an embodiment of the present invention. FIG. 5 is an exploded perspective view showing the main components of the hollow motor, nut body, spindle, and piston, respectively, in a hydraulic actuator using a hollow motor according to an embodiment of the present invention. Specific details for implementing the invention

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached illustrative drawings.

[0025] Referring to the drawings, a hydraulic actuator using a hollow motor according to an embodiment of the present invention comprises a cylinder body (10), a housing (20), a hollow motor (30), a nut body (40) and a spindle (50) coupled by a ball screw method, a piston (60), and a lower cover (70).

[0026] The cylinder body (10) is configured to form a pressure chamber (11) inside and to have a fluid inlet / outlet (12) on one side that is structured to allow communication with the outside. In this case, the piston (60) is installed inside the pressure chamber (11) so as to be movable in the axial direction.

[0027] The housing (20) is a member coupled to the cylinder body (10) and is configured to house the hollow motor (30), the nut body (40), and the spindle (50) respectively inside.

[0028] The hollow motor (30) is installed inside the housing (20) and is configured to include a stator (31) that becomes magnetized when an operating power source is applied, and a rotor (32) that rotates according to the magnetization of the stator (31). At this time, the stator (31) and the rotor (32) are arranged concentrically with respect to the axis center of the spindle (50), and in particular, the rotor (32) is installed to be rotatable inside the stator (31).

[0029] The nut body (40) is a member installed at the axial center of the hollow motor (30) and is installed to rotate in conjunction with the rotor (32). That is, the nut body (40) is configured to be arranged concentrically with the hollow motor (30) with respect to the axial center of the spindle (50).

[0030] The spindle (50) is installed to be engaged with the inner surface of the nut body (40) and to move in the axial direction. To this end, the inner surface of the nut body (40) and the outer surface of the spindle (50) are each configured to have a spiral tooth-shaped portion for engagement.

[0031] The piston (60) is a member installed inside the cylinder body (10) and is configured to be installed so as to be axially articulated within the pressure chamber (11) of the cylinder body (10) according to the axial movement of the spindle (50).

[0032] The lower cover (70) is a member installed at the bottom of the housing (20) and is configured to house a control printed circuit board (71) inside.

[0033] Meanwhile, in a hydraulic actuator using a hollow motor according to an embodiment of the present invention, the rotor (32) of the hollow motor (30) and the nut body (40) are configured to be coupled in a mutually constrained manner along the rotational direction. That is, the rotor (32) and the nut body (40) can rotate as a single unit according to the magnetization of the stator (31) when an operating power source is applied.

[0034] To this end, in the hollow motor (30), the inner surface of the rotor (32) and the outer surface of the nut body (40) are configured to be constrained in the direction of rotation by spline coupling or key coupling for integrated rotation. For example, the inner surface of the rotor (32) and the outer surface of the nut body (40) may each be configured to have a spline extending in the axial direction formed therein, or a keyway extending in the axial direction formed therein.

[0035] In addition, in a hydraulic actuator using a hollow motor according to an embodiment of the present invention, the piston (60) is configured to have a shaft portion (61) that extends long along the axial direction of the pressure chamber (11), and a skirt portion (62) that is arranged in layers in a plurality of numbers along the longitudinal direction of the shaft portion (61). That is, in the piston (60), the skirt portion (62) is configured to be arranged in layers along the axial direction of the pressure chamber (11) with respect to the shaft portion (61).

[0036] Additionally, a sealing member (80) that closely adheres to the inner surface of the pressure chamber (11) is configured to be installed between the plurality of skirt portions (62). In this case, the sealing member (80) is configured to have a hollow boss portion (81) mounted on the shaft portion (61) of the piston (60), and a lip portion (82) that extends radially outward from the boss portion (81) and closely adheres to the inner surface of the pressure chamber (11).

[0037] Meanwhile, a hydraulic actuator using a hollow motor according to an embodiment of the present invention further comprises a fixed radial bearing (90) installed to support the nut body (40) in a rotational direction inside the housing (20), a thrust bearing (100) installed to support the nut body (40) in an axial direction inside the housing (20), and a movable radial bearing (110) installed between the spindle (50) and the piston (60) to support the relative rotation of the spindle (50) with respect to the piston (60).

[0038] In this case, the fixed radial bearing (90) is installed to rotatably support both ends of the nut body (40) inside the cylinder body (10) and inside the housing (20). That is, the fixed radial bearing (90) is installed to rotatably support one end of the nut body (40) inside the cylinder body (10) and to rotatably support the other end of the nut body (40) inside the housing (20).

[0039] Additionally, the thrust bearing (100) is installed between the free end of the nut body (40) and the housing (20) to rotatably support the free end of the nut body (40) axially with respect to the housing (20). For example, the thrust bearing (100) may be installed in a manner that rotatably supports the free end of the nut body (40) facing the piston (60) inside the housing (20) axially.

[0040] Additionally, the movable radial bearing (110) is installed between the spindle (50) and the piston (60) and is configured to perform the role of ensuring smooth relative rotation of the spindle (50) with respect to the piston (60).

[0041] To this end, the movable radial bearing (110) is installed such that its outer ring is mounted and supported on a locking end (63) formed to extend downward from the bottom portion of the piston (60), and its inner ring is mounted and supported on a seating end (51) formed in a stepped manner with a reduced cross-sectional area at the top portion of the spindle (50). That is, the piston (60) is configured to have the locking end (63) to mount the outer ring of the movable radial bearing (110), and the spindle (50) is configured to have the seating end (51) to mount the inner ring of the movable radial bearing (110).

[0042] Meanwhile, in a hydraulic actuator using a hollow motor according to an embodiment of the present invention, the cylinder body (10) is configured to have a snap ring (120) fastened to an inner circumference for axial fixation of the fixed radial bearing (90).

[0043] In addition, the hydraulic actuator using a hollow motor according to an embodiment of the present invention further comprises an O-ring (121) installed to maintain an effective airtight seal between the cylinder body (10) and the housing (20).

[0044] In addition, the hydraulic actuator using a hollow motor according to an embodiment of the present invention further comprises a dowel pin (122) installed to assist in the provisional fastening of the parts between the cylinder body (10) and the housing (20) during assembly.

[0045] Accordingly, in the hydraulic actuator using a hollow motor according to the embodiment of the present invention configured as above, the rotation of the nut body (40) in a linked manner can be achieved according to the rotation of the hollow motor (30), and the piston (60) moves axially within the pressure chamber (11) of the cylinder body (10) through the axial movement of the spindle (50) achieved by the rotation of the nut body (40), thereby enabling pressurization of the fluid stored inside the pressure chamber (11), so that the operation of external devices can be realized by the pressure of the compressed fluid.

[0046] At this time, the hydraulic actuator according to the embodiment of the present invention can provide a motor-driven hydraulic actuator by applying a ball screw assembly structure between the nut body (40), which operates in a rotational direction accompanying the operation of the hollow motor (30), and the spindle (50), which operates in an axial direction.

[0047] In addition, the hydraulic actuator according to the embodiment of the present invention can arrange the hollow motor (30) and the nut body (40) concentrically with respect to the axial center of the spindle (50) through a spline coupling or key coupling between the rotor (32) of the hollow motor (30) and the nut body (40), thereby allowing the radial package of the hydraulic actuator to be reduced, and also enables the prevention of leakage and smooth generation of hydraulic pressure inside the pressure chamber (11) of the cylinder body (10) through the multi-structured sealing member (80) applied to the piston (60).

[0048] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. Therefore, the scope of protection of the present invention should be interpreted by the claims below, and all technical concepts within an equivalent scope should be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0049] 10-Cylinder body 11-Pressure chamber 12-Entrance 20-Housing 30-Motor 31-Stator 32-rotor 40-nut body 50-Spindle 51-Filing end 60-Piston 61-Shaft 62-Skirt section 63-Catching end section 70-Lower cover 80-Sealing member 81-Boss Department 82-Rip Department 90-Stationary Radial Bearing 100-thrust bearing 110-Mountable radial bearing 120-Snap ring

Claims

Claim 1 A hydraulic actuator using a hollow motor comprising: a cylinder body forming a pressure chamber; a housing coupled to the cylinder body; a hollow motor installed inside the housing; a nut body installed to be coupled in a rotational direction with the rotor of the hollow motor and having a toothed portion provided on its inner surface; a spindle installed to be coupled in an axial direction with a corresponding toothed portion formed on its outer surface to be coupled to the inner surface of the nut body; a piston installed to be coupled in an axial direction inside the pressure chamber according to the axial movement of the spindle; a fixed radial bearing supporting the nut body in a rotational direction inside the housing; a thrust bearing supporting the nut body in an axial direction inside the housing; and a movable radial bearing installed between the spindle and the piston to support the relative rotation of the spindle with respect to the piston; wherein the piston has a locking end for mounting the outer ring of the movable radial bearing, and the spindle has a seating end for mounting the inner ring of the movable radial bearing. Claim 2 A hydraulic actuator using a hollow motor according to claim 1, characterized in that the rotor and the nut body are coupled to be mutually constrained along the direction of rotation. Claim 3 A hydraulic actuator using a hollow motor according to claim 2, characterized in that the inner surface of the rotor and the outer surface of the nut body are configured to be constrained in the rotational direction by spline coupling or key coupling. Claim 4 A hydraulic actuator using a hollow motor according to claim 1, wherein the piston comprises a shaft portion extending along the axial direction of the pressure chamber; and a plurality of skirt portions arranged along the longitudinal direction of the shaft portion, and a sealing member installed between the plurality of skirt portions to be in close contact with the inner surface of the pressure chamber. Claim 5 A hydraulic actuator using a hollow motor according to claim 4, wherein the sealing member comprises a hollow boss portion mounted on the shaft portion; and a lip portion extending radially outward from the boss portion and in close contact with the inner surface of the pressure chamber. Claim 6 delete Claim 7 A hydraulic actuator using a hollow motor according to claim 1, characterized in that the fixed radial bearing is installed to rotatably support both ends of the nut body inside the cylinder body and inside the housing. Claim 8 A hydraulic actuator using a hollow motor, wherein the thrust bearing is installed between the free end of the nut body and the housing and rotatably supports the free end of the nut body axially with respect to the housing. Claim 9 delete Claim 10 A hydraulic actuator using a hollow motor according to claim 1, wherein the cylinder body is provided with a snap ring fastened to the inner circumference for axial fixation of the fixed radial bearing. Claim 11 A hydraulic actuator using a hollow motor according to claim 1, further comprising an O-ring installed to maintain airtightness between the cylinder body and the housing. Claim 12 A hydraulic actuator using a hollow motor according to claim 1, further comprising a dowel pin installed for provisional fastening between the cylinder body and the housing.

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