High density actuator with in-motor gearbox

Abstract

A high density actuator comprising a motor including a stator, a rotor, a rotor hub, a rotor bearing, an actuator base, and a rolling bearing, and a transmission located within the rotor hub. The high density actuator is configured such that the transmission is located within an inner diameter of the motor. The transmission can be, for example, a cycloidal transmission, a planetary transmission, and a harmonic transmission.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 310,098, filed Feb. 14, 2022, which is incorporated herein by reference.

[0002] The present disclosure relates to high density actuators with in-motor transmissions. [Background technology]

[0003] Motors and gearboxes are used to actuate various devices. For devices such as exoskeletons, anthropomorphic robots, and other low-volume, high-power applications, it is advantageous for the combination of both components to be as compact as possible. This leads to a denser motor-gearbox combination, called an actuator. However, conventional gearboxes are stacked on top of the motor casing, leading to an increased thickness of the motor-gearbox structure.

[0004] Therefore, there is a need for high density, low profile motor and transmission structures. Summary of the Invention

[0005] The present disclosure provides a high density actuator, the high density actuator comprising: a motor including a stator, a rotor, a rotor hub, a rotor bearing, an actuator base, and a rolling bearing;

[0006] a transmission positioned within the rotor hub;

[0007] The transmission is located within the inner diameter of the motor.

[0008] The present disclosure also provides a high density actuator in which the gearbox has an overall diameter that is smaller than the inner diameter of the stator and the inner diameter of the rotor.

[0009] The present disclosure further provides a high density actuator including a cycloidal, planetary, or harmonic transmission.

[0010] The present disclosure also provides a high density actuator, wherein the transmission is a cycloid transmission, the cycloid transmission comprising:

[0011] a cycloidal ring gear configured to rotate within the rotor hub via a rotor bearing;

[0012] an input shaft configured to follow an eccentric motion induced by a cycloidal disk having an outer surface configured to roll within a cycloidal ring gear via a roller pin;

[0013] and an output pin positioned within a corresponding opening in the cycloidal disk for operatively connecting the cycloidal disk to an output shaft for transmitting torque from the rotor to the output shaft, and further operatively connected to the actuator base via a rolling bearing.

[0014] The present disclosure further provides a high density actuator, wherein the transmission is a cycloid transmission, the cycloid transmission comprising:

[0015] a cycloidal ring gear configured to rotate within the rotor hub via a rotor bearing;

[0016] an input shaft configured to follow an eccentric motion induced by a cycloidal disk having an outer surface configured to roll within a cycloidal ring gear via a roller pin;

[0017] and an output pin positioned within a corresponding opening in the cycloidal disk for operatively connecting the cycloidal disk to an output shaft for transmitting torque from the rotor to the output shaft, and further operatively connected to the actuator base via a rolling bearing.

[0018] The present disclosure further provides a high density actuator, wherein the transmission is a cycloid transmission, the cycloid transmission comprising:

[0019] a cycloidal ring gear configured to rotate within the rotor hub via a rotor bearing;

[0020] an input shaft configured to follow an eccentric motion induced by a cycloidal disk having an outer surface configured to roll within a cycloidal ring gear via a roller pin;

[0021] and an output pin positioned within a corresponding opening in the cycloidal disk for operatively connecting the cycloidal disk to an output shaft for transmitting torque from the rotor to the output shaft, and further operatively connected to the actuator base via a rolling bearing.

[0022] The present disclosure also provides a high density actuator, wherein the transmission is a cycloid transmission, the cycloid transmission comprising:

[0023] a cycloidal ring gear configured to rotate within the rotor hub via a rotor bearing;

[0024] an input shaft configured to follow an eccentric motion induced by a cycloidal disk having an outer surface configured to roll within a cycloidal ring gear via a roller pin;

[0025] and an output pin positioned within a corresponding opening in the cycloidal disk for operatively connecting the cycloidal disk to an output shaft for transmitting torque from the rotor to the output shaft, and further operatively connected to the actuator base via a rolling bearing.

[0026] The present disclosure further provides a high density actuator, wherein the transmission is a cycloid transmission, the cycloid transmission comprising:

[0027] a cycloidal ring gear configured to rotate within the rotor hub via a rotor bearing;

[0028] an input shaft configured to follow an eccentric motion induced by a cycloidal disk having an outer surface configured to roll within a cycloidal ring gear via a roller pin;

[0029] and an output pin positioned on the corresponding rolling elements in corresponding openings in the cycloidal disk to operably connect the cycloidal disk to an output shaft to transmit torque from the rotor to the output shaft, and further operably connected to the actuator base via a rolling bearing.

[0030] The present disclosure also provides a high density actuator enclosed within an actuator housing.

[0031] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 illustrates a cross-sectional view of a high density actuator with in-motor transmission using an in-rotor cycloidal transmission according to an exemplary embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective cross-sectional view of the rotor internal cycloid transmission of FIG. 1. [Diagram 3] FIG. 2 is a top cross-sectional view of the rotor-internal cycloidal transmission of FIG. 1. [Figure 4] FIG. 2 is a perspective exploded view of the rotor internal cycloid transmission of FIG. 1. [Diagram 5] FIG. 2 is a top cross-sectional view of an intra-rotor cycloidal transmission according to a first alternative embodiment of the present disclosure. [Figure 6] FIG. 13 is a cross-sectional view of a high density actuator with in-motor transmission according to a second alternative embodiment of the present disclosure. [Figure 7] FIG. 13 is a top cross-sectional view of an intra-rotor cycloidal transmission according to a third alternative embodiment of the present disclosure. [Figure 8] FIG. 13 is a top cross-sectional view of an intra-rotor cycloidal transmission according to a fourth alternative embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Like reference numbers used in different drawings indicate like elements.

[0034] In general terms, non-limiting exemplary embodiments of the present disclosure provide a high density actuator with an in-motor transmission. In exemplary embodiments, the in-motor transmission is an in-rotor cycloidal transmission whose overall diameter is smaller than the inner diameter of the stator and rotor and which is partially or completely inserted into the actuator. Although the disclosed exemplary embodiments are described using an in-rotor cycloidal transmission, it should be understood that other transmissions, such as planetary or harmonic transmissions, can be used as well.

[0035] 1-4, a high density actuator 30 according to an exemplary embodiment of the present disclosure includes a stator 32, a rotor 34, and a housing 20 in which a cycloidal transmission is positioned. The cycloidal transmission is comprised of a cycloidal ring gear 12, a roller pin 13, a cycloidal disk 14, an input shaft 16, an output shaft 18, and an output pin 19.

[0036] The cycloidal transmissions 12, 13, 14, 16, 18, 19 are positioned in the actuator 30 so that the rotor bearings 37 allow the rotor hub 36 to rotate around the cycloidal ring gear 12. The input torque of the rotor 34 and the rotor hub 36 is transmitted through the input shaft 16. While the input shaft 16 rotates, its center follows an eccentric motion, allowing for precise movement from the cycloidal disk 14. The outer surface of the cycloidal disk 14 rolls on the roller pin 13, which results in the transmission of torque to the output pin 19. The output pin 19 is inserted into the output shaft 18, which transmits the torque to the output shaft 18. The output shaft 18 is connected to the actuator housing base 22 via the rolling bearings 24. The actuator housing cover 26 fixes the actuator 30 and the cycloidal transmissions 12, 13, 14, 16, 18, 19 in the housing 20.

[0037] Referring to FIG. 5, in a first alternative embodiment of a high density actuator 30 with in-motor transmission, the roller pin 13 (see FIG. 3) may be omitted and the shape of the inner portion of the cycloidal ring gear 12a and the outer surface of the cycloidal disc 14a are adapted to provide corresponding protrusions.

[0038] Referring to FIG. 6, in a second alternative embodiment of a high density actuator 30 with in-motor gearbox, the cylindrical roller pins 13 may be replaced with variable diameter rollers 13b, and the shape of the inner portion of the cycloidal ring gear 12b and the outer surface of the cycloidal disk 14b are adapted to provide corresponding protrusions.

[0039] Referring to FIG. 7, in a third alternative embodiment of a high density actuator 30 with in-motor gearbox, the cylindrical roller pin 13 may be replaced with a bearing 13c, and the shape of the inner portion of the cycloidal ring gear 12c is adapted to provide structural support for the bearing.

[0040] Referring to FIG. 8, in a fourth alternative embodiment of a high density actuator 30 with an in-motor transmission, the cycloidal disk 14 may have rolling elements 15, such as bearings, inserted between the cycloidal disk 14 and the output pin 19d to transmit the rotational motion of the cycloidal disk 14 to the output pin 19d with lower friction.

[0041] It should be noted that while the present disclosure has been described by certain non-limiting exemplary embodiments and examples thereof, it will be apparent to those skilled in the art that modifications may be made to the specific embodiments without departing from the scope of the present disclosure.

Claims

1. 1. A high density actuator, comprising: a motor including a stator (32), a rotor (34), a rotor hub (36), a rotor bearing (37), an actuator base (22), an output shaft (18), and a rolling bearing (24), wherein the rotor (34) is connected to the rotor hub (36), the rotor hub (36) and the output shaft (18) form an accommodation space, the radial dimension of the accommodation space being smaller than the inner diameter of the rotor (34), and the output shaft (18) is operably connected to the actuator base (22) via the rolling bearing (24); a cycloidal transmission disposed in the accommodation space, the cycloidal transmission comprising: a cycloidal ring gear (12, 12a, 12b, 12c) configured to rotate the rotor hub (36) via the rotor bearing (37); a cycloidal disk (14, 14a, 14b) having an outer surface configured to roll within the cycloidal ring gear (12, 12a, 12b, 12c) via a rolling medium (13, 13b, 13c); an input shaft (16) connected to the rotor hub (36) and generating eccentric motion in response to rotation of the rotor hub (36) to operate the cycloid disks (14, 14a, 14b); a plurality of output pins (19) disposed within corresponding openings in the cycloidal discs (14, 14a, 14b), operatively connecting the cycloidal discs (14, 14a, 14b) to the output shaft (18) and transmitting torque from the rotor (34) to the output shaft (18).

2. The high-density actuator of claim 1 , wherein the cycloidal transmission has an overall diameter that is smaller than a radial dimension of the receiving space.

3. A high-density actuator as described in any one of claims 1 or 2, wherein the rotor hub (36) has a recess with an opening, and the output shaft (18) substantially closes the opening to form the accommodating space.

4. A high-density actuator as described in any one of claims 1 or 2, wherein the rolling medium (13, 13b, 13c) includes a roller pin (13).

5. A high-density actuator as described in any one of claims 1 or 2, wherein the rolling medium (13, 13b, 13c) includes corresponding protrusion portions formed between the cycloidal disc (14a) and the cycloidal ring gear (12a).

6. A high-density actuator as described in any one of claims 1 or 2, wherein the rolling medium (13, 13b, 13c) includes rollers (13b) having individual variable diameters.

7. A high-density actuator as described in any one of claims 1 or 2, wherein the rolling medium (13, 13b, 13c) includes a bearing (13c).

8. A high-density actuator as described in any one of claims 1 or 2, wherein the rolling medium (13, 13b, 13c) includes a bearing (13), the cycloidal transmission further comprises a rolling element (15) correspondingly arranged within the opening of the cycloidal disc (14), and the output pin (19d) is a cycloidal transmission correspondingly arranged within the rolling element.

9. 3. The high density actuator of claim 1, wherein the actuator base (22) forms the bottom of an actuator housing (20), and the high density actuator is enclosed within the actuator housing (20).

10. The high density actuator of claim 9, further comprising a housing cover (26) that secures the high density actuator within the actuator housing (20).

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