Rotary actuator

Abstract

The rotary actuator includes a housing having a first end and a second end spaced apart from the first end along an axis. The housing defines a cavity extending circumferentially about an axis. The output shaft is arranged coaxially with the axis. An output shaft extends outwardly from the cavity through the first end. A drive system is disposed in the cavity and is axially spaced from the first end. A gearbox is disposed in the cavity between the output shaft and the drive system. A gearbox is coupled to the drive system and the output shaft. A rotation controller is disposed in the cavity between the drive system and the second end. The rotation controller is configured to actuate the drive system to adjust an angular position of the output shaft.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 346,356 filed on May 27, 2022 and U.S. Non-Provisional Patent Application No. 18 / 073,633 filed on December 2, 2022, the entire disclosures of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to rotary actuators, and more particularly to a rotary actuator including a drive system and a rotary controller arranged in a one-piece housing. Background Art

[0004] Waves may disturb the ship during operation and may cause the ship to rotate about one or more axes. That is, during operation on a waterway, the ship may be subject to rotational motions, such as roll, pitch and / or sway. A stabilizer system may be mounted to the ship to counteract the effects of waves and stabilize the ship during operation on a waterway. For example, the stabilizer system may include fins mounted to a rotary actuator. The rotary actuator may rotate the fins to a desired angular position, thereby generating pressure around the ship, which may reduce interference from waves and thereby improve the stability of the ship. Since the rotary actuator is submerged during operation of the stabilizer system, it is desirable to provide alternative designs and configurations to minimize water intrusion into the rotary actuator. Summary of the invention

[0005] According to an example embodiment, a rotary actuator includes a hollow housing having a first end and a second end spaced apart from the first end along an axis. The hollow housing defines a cavity extending from the first end to the second end. An output shaft is arranged coaxially with the axis. The output shaft extends outward from the cavity through the first end. A drive system is disposed in the cavity and is drivably connected to the output shaft. A gearbox is disposed in the cavity and is axially arranged between the output shaft and the drive system. The gearbox may be a strain wave gearbox. The gearbox is drivably connected to the drive system and the output shaft. A rotary controller is arranged in the cavity between the drive system and the second end. The rotary controller is configured to actuate the drive system to adjust the angular position of the output shaft.

[0006] In example embodiments, the drive system and the gearbox may be arranged coaxially with the axis.

[0007] In example embodiments, the housing may be constructed from a single piece.

[0008] In an example embodiment, the rotary actuator may include a first seal disposed at the first end and a second seal disposed at the second end. The first seal and the second seal may be configured to prevent fluid communication between the cavity and an environment surrounding the housing via the respective ends.

[0009] In an example embodiment, the rotary actuator is designed to operate while it is submerged in a fluid, such as saline.

[0010] In an example embodiment, a drive system may include an electric motor having a rotor shaft. The drive system may also include a bearing housing defining a housing cavity extending axially through the bearing housing. The rotor shaft may partially extend through the housing cavity. The drive system may also include an encoder magnet connected to the rotor shaft and capable of being detected by a rotation controller. The encoder magnet may be disposed within the housing cavity. The drive system may also include a shield covering the housing cavity. The shield may be disposed between the encoder magnet and the rotation controller. The bearing housing and the shield may be configured to prevent fluid communication through the cavity.

[0011] In an example embodiment, the rotary controller may be covered with a potting compound. The potting compound may fill the cavity around the rotary controller and seal against the inner surface of the housing.

[0012] In an example embodiment, the rotary actuator may include an idler shaft arranged coaxially with the axis. The idler shaft may extend outwardly from the cavity through the second end. A rotary controller may be disposed between the drive system and the idler shaft. The rotary controller may include a first sensor configured to detect an angular position of a rotor shaft of the electric motor and a second sensor configured to detect an angular position of the idler shaft. The first sensor and the second sensor may be axially spaced apart from each other. The first sensor and the second sensor may be disposed within the cavity and arranged coaxially with the axis.

[0013] In an example embodiment, the hollow housing includes a plurality of axial segments defining a plurality of inner diameters of the longitudinal cavity. A first segment surrounded by an immediately adjacent second segment and a third segment has an inner diameter greater than the corresponding diameters of the second segment and the third segment. A rotary controller is housed within the first segment.

[0014] In an example embodiment, the hollow housing includes an opening arranged: i) between the first end and the second end, and ii) transverse to the axis. A cable extends through the opening and is connected to the rotation controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A cross-sectional view along the axis of an exemplary rotary actuator is illustrated.

[0016] Figure 2 The picture shows the unsealed Figure 1 A cross-sectional view of a portion of a rotary actuator.

[0017] Figure 3 Pictured Figure 1 An enlarged cross-sectional view of a portion of a rotary actuator.

[0018] Figure 4 Pictured Figure 1 An enlarged cross-sectional view of another portion of the rotary actuator.

[0019] Figure 5 Pictured Figure 1 An enlarged cross-sectional view of another portion of the rotary actuator.

[0020] Figure 6 Pictured Figure 1 An enlarged cross-sectional view of another portion of the rotary actuator.

[0021] Figure 7 Pictured Figure 1 An enlarged cross-sectional view of another portion of the rotary actuator.

[0022] Figure 8 Pictured Figure 1 Block diagram of the electronic communication network of a rotary actuator. DETAILED DESCRIPTION

[0023] Embodiments of the present disclosure are described herein. It should be understood that the same reference numerals appearing in different figures identify the same or functionally similar structural elements. In addition, it should be understood that the disclosed embodiments are examples only, and other embodiments may take various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show the details of a particular component. Therefore, the specific structural and functional details disclosed herein should not be interpreted as being restrictive, but only as a representative basis for teaching those skilled in the art to adopt embodiments in various ways. As will be understood by those of ordinary skill in the art, the various features illustrated and described with reference to any of the drawings in the drawings may be combined with the features illustrated in one or more other drawings to produce embodiments that are not explicitly illustrated or described. The combination of the illustrated features provides representative embodiments for typical applications. However, for specific applications or implementations, various combinations and modifications of features consistent with the teachings of the present disclosure may be desired.

[0024] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the scope of the present disclosure. Unless otherwise specified, all technical terms and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. Now the following example methods, devices and materials are described, but any method, device or material similar or equivalent to those methods, devices or materials described herein may also be used in the practice or testing of the present disclosure.

[0025] The rotary actuator may include a housing having multiple portions to respectively house components of the rotary actuator. For example, a portion of the housing may house a controller, and a separate portion of the housing may house an electric motor. In such examples, the portions of the housing are sealed together, for example, to prevent water from intruding into the housing. However, sealing the multiple portions together may increase the likelihood of water intrusion due to manufacturing defects in one or more seals between the respective portions.

[0026] Advantageously, in an exemplary embodiment of the present disclosure, the rotary actuator includes a housing defining a cavity. The drive system is arranged in the cavity. The output shaft is arranged coaxially with the drive system and extends from the cavity. The gearbox is arranged in the cavity and coaxial with the drive system. The gearbox is coupled to the drive system and the output shaft. The rotary controller is arranged in the cavity on a side of the drive system opposite the gearbox. By arranging the components of the rotary actuator in the cavity, the rotary actuator eliminates sealing joints between multiple housing parts that house separate components, which can reduce the possibility of water intrusion into the cavity.

[0027] Referring to the accompanying drawings, a rotary actuator 100 is generally shown. The rotary actuator 100 includes a housing 102 and a plurality of components at least partially contained in the housing. The housing 102 may be a unitary structure, i.e., a one-piece structure. The unitary structure eliminates joints between a plurality of housing components, which reduces the possibility of water intrusion into the housing 102. The housing 102 may be any suitable material for withstanding forces and environmental influences of being immersed in water, such as salt water. For example, the housing 102 may be a non-corrosive metal, such as aluminum, stainless steel, etc. The housing 102 may have any suitable coating, such as a powder coating. The coating is applied externally to the housing 102 to reduce the possibility of corrosion caused by the housing 102 being immersed in water, such as salt water. Additionally, the coating may be applied internally to the housing 102.

[0028] Reference Figure 1, the housing 102 includes a first end 104 and a second end 106 spaced apart from the first end 104 along an axis A. The housing 102 includes a wall 108 extending from the first end 104 to the second end 106 along the axis A. Additionally, the wall 108 extends annularly around the axis A. That is, the housing 102 has a tubular shape and can be described as a hollow housing. The wall 108 defines a cavity 110 extending circumferentially around the axis A and axially along the axis A. The wall 108 is open at the first end 104 and the second end 106. That is, the cavity 110 extends through the first end 104 of the housing 102 along the axis A and through the second end 106 of the housing 102. During assembly of the rotary actuator 100, components of the rotary actuator 100 are inserted through one of the first end 104 or the second end 106.

[0029] The wall 108 includes an inner surface 184 extending circumferentially about the axis A and an outer surface 186 extending circumferentially about the inner surface 184. The wall 108 has a thickness radially determined from the inner surface 184 to the outer surface 186 relative to the axis A. The thickness can vary along the housing 102, for example, from the first end 104 to the second end 106. For example, the outer surface 186 can have a substantially uniform diameter from the first end 104 to the second end 106 of the housing 102. Additionally, the diameter of the inner surface can vary from the first end 104 to the second end 106 of the housing 102, for example, to receive and / or retain various components of the rotary actuator 100 in the housing 102.

[0030] Go to Figure 2, the wall 108 may include a plurality of axial segments or portions 112 and a plurality of locator surfaces 114. Each locator surface 114 may extend from one corresponding axial portion 112 to another corresponding axial portion 112. Each axial portion 112 extends along some but less than the entire length of the wall 108. As an example, the axial portions 112 may extend continuously, i.e., one after another, from the first end 104 of the wall 108 to the second end 106. In such an example, the locator surfaces 114 extending between adjacent axial portions 112 may extend radially relative to the axis A. As another example, the axial portions 112 may be axially spaced apart from each other. In such an example, the locator surfaces 114 extending between adjacent axial portions 112 may extend obliquely relative to the axis A and in a first direction d1 from the first end 104 toward the second end 106. As another example, the axial portions 112 may overlap with adjacent axial portions 112. In such an example, the locator surface 114 extending between adjacent axial portions 112 may extend obliquely relative to the axis A and in a second direction d2 opposite to the first direction d1, for example, from the second end 106 to the first end 104. As yet another example, at least some of the axial portions 112 may extend continuously, at least some of the axial portions 112 may overlap with one or more adjacent axial portions 112, and / or at least some of the axial portions 112 may be axially spaced apart from one or more adjacent axial portions 112.

[0031] The wall 108 has a different thickness at each axial portion 112 relative to the (one or more) immediately adjacent axial portion 112. That is, each axial portion 112 is defined by a substantially uniform thickness. Each axial portion 112 can be sized, i.e. extended, along the axis A to engage one or more components of the rotary actuator 100. As an example, one or more axial portions 112 can radially constrain one or more components of the rotary actuator 100. In other words, one or more axial portions 112 can be radially aligned with respect to the axis A (one or more) components. (One or more) components can abut (one or more) axial portions 112 circumferentially around the axis A. For example, (one or more) axial portions 112 can be connected to (one or more) corresponding components in a non-rotatable manner, for example, via a press fit connection. As another example, (one or more) axial portions 112 can engage (one or more) components via a sliding fit connection. As used herein, "connected in a non-rotatable manner" means that the components are connected so that whenever one of the components rotates, all components rotate; and relative rotation between the components is impossible.

[0032] Additionally or alternatively, the locator surfaces 114 between adjacent axial segments or portions 112 can axially constrain, i.e., limit or prevent movement of one or more components engaged with the adjacent axial portions 112 along the axis A. In other words, the locator surface(s) 114 can position the component(s) relative to the first end 104 and the second end 106 of the housing 102. For example, the locator surface(s) 114 can axially constrain the one or more components in the first direction d1 or the second direction d2.

[0033] The first axial portion 112a may extend from the first end 104 of the housing 102 to a first locator surface 114a. The first locator surface 114a may extend radially inwardly from the first axial portion 112a to the second axial portion 112b relative to the axis A. The first locator surface 114a axially constrains the first seal 120a in the first direction d1. The first axial portion 112a radially constrains the first seal 120a.

[0034] The second axial portion 112b may extend from the first locator surface 114a to the second locator surface 114b. The second locator surface 114b may extend radially outward from the second axial portion 112b to the third axial portion 112c relative to the axis A. The second locator surface 114b axially constrains the outer retainer 116 in the second direction d2.

[0035] The third axial portion 112c can be arranged radially inwardly of the first axial portion 112a. The third axial portion 112c can extend from the second locator surface 114b to the third locator surface 114c. The third locator surface 114c can extend radially inwardly from the third axial portion 112c to the fourth axial portion 112d relative to the axis A. The third axial portion 112c can be designed, i.e., sized and shaped to receive the outer retainer 116. That is, the third axial portion 112c can extend along the axis A so that the outer retainer 116 can be inserted between the second locator surface 114b and the third locator surface 114c. The third locator surface 114c axially constrains the outer retainer 116 in the first direction d1. The third axial portion 112c can radially constrain the outer retainer 116.

[0036] The fourth axial portion 112d can extend from the third locator surface 114c to the fourth locator surface 114d. The fourth axial portion 112d can be radially inward from the third axial portion 112c to the fifth axial portion 112e relative to the axis A. The fourth axial portion 112d can be, for example, radially inwardly arranged relative to the second axial portion 112b. Alternatively, the fourth axial portion 112d can be radially aligned with the second axial portion 112b. The fourth locator surface 114d can extend radially inward from the fourth axial portion 112d.

[0037] The fourth locator surface 114d axially constrains the output bearing 150 in the first direction d1 within the cavity 110 .

[0038] The fourth axial portion 112 d radially constrains the output bearing 150 .

[0039] The fifth axial portion 112e may extend from the fourth locator surface 114d to the fifth locator surface 114e. The fifth locator surface 114e may extend radially inward relative to the axis A from the fifth axial portion 112e to a sixth axial portion 112f.

[0040] The sixth axial portion 112f can extend from the fifth locator surface 114e to the sixth locator surface 114f. The sixth locator surface 114f can extend radially outward from the sixth axial portion 112f to the seventh axial portion 112g relative to the axis A. The sixth locator surface 114f can axially constrain the gearbox 200 in the second direction d2. Additionally, the sixth locator surface 114f can radially constrain the fixed gear 202 of the gearbox 200 (as discussed further below).

[0041] The seventh axial portion 112g may extend from the sixth locator surface 114f to the seventh locator surface 114g. The seventh locator surface 114g may extend obliquely from the seventh axial portion 112g to the eighth axial portion 112h relative to the axis A. For example, the seventh locator surface 114g may extend radially outward from the seventh axial portion 112g and along the first direction d1 to the eighth axial portion 112h. In such an example, the eighth axial portion 112h may be axially offset relative to the seventh axial portion 112g, for example, spaced apart from the seventh axial portion. The seventh axial portion 112g may radially constrain the gearbox 200, the elastic member 152, and the first drive bearing housing 342. The seventh locator surface 114g may axially constrain the extension 348 of the first drive bearing housing 342 in the second direction d2.

[0042] The eighth axial portion 112h can extend from the seventh locator surface 114g to the eighth locator surface 114h. The eighth locator surface 114h can extend radially inward from the eighth axial portion 112h to the ninth axial portion 112i relative to the axis A. Additionally, the eighth axial portion 112h can be designed to allow axial movement of the extension 348, for example to allow thermal contraction and / or thermal expansion of the extension 348 during operation of the rotary actuator 100. That is, the eighth axial portion 112h can extend farther along the axis A than the extension 348. The eighth locator surface 114h axially constrains the extension 348 in the first direction d1.

[0043] The ninth axial portion 112i can be radially aligned with the seventh axial portion 112g. The ninth axial portion 112i can extend from the eighth locator surface 114h to the ninth locator surface 114i. The ninth locator surface 114i can extend radially outward from the ninth axial portion 112i to the tenth axial portion 112j relative to the axis A. The ninth locator surface 114i can be designed to axially constrain the electric motor 302 in the second direction d2.

[0044] The tenth axial portion 112j may extend from the ninth locator surface 114i to the tenth locator surface 114j. The tenth locator surface 114j may extend radially outwardly from the tenth axial portion 112j to the eleventh axial portion 112k relative to the axis A. The tenth axial portion 112j radially constrains the electric motor 302 and the second drive bearing housing 352 .

[0045] The eleventh axial portion 112k may extend from the tenth locator surface 114j to the eleventh locator surface 114k. The eleventh locator surface 114k may extend radially inward relative to the axis A from the eleventh axial portion 112k to the twelfth axial portion 112l.

[0046] The eleventh axial portion 112k includes an opening 122 extending radially through the wall 108. The opening 122 extends transversely relative to the axis A. A cable 124 extends through the opening 122. The cable 124 includes one or more wires that: i) provide power to the rotation controller 400, ii) facilitate electronic communication with the rotation controller 400, and iii) facilitate grounding connection between the inner surface 184 of the housing 102 and the ship. A cable gland 126 is disposed in the opening 122. The cable gland 126 includes a body 128 and a cover 132 extending through the opening 122. The cable gland 126, i.e., the body 128 and the cover 132 define a cable cavity 130 extending circumferentially around an axis R transverse to the axis A. The cable 124 extends through the cable cavity 130. That is, the cable cavity 130 is designed, i.e., sized and shaped to receive the cable 124. Specifically, the cable cavity 130 is designed to abut the cable 124 completely around the axis R.

[0047] The body 128 includes a base disposed in the cavity 110 of the housing 102. The base abuts the eleventh locator surface 114k. That is, the eleventh locator surface 114k axially constrains the cable gland 126 in the first direction d1. The body 128 includes a wall extending axially from the base through the opening 122. The wall abuts the housing 102 completely circumferentially around the opening 122. The base extends radially outward from the wall relative to the axis R. That is, the base has a larger diameter than the opening 122.

[0048] The wall of the body 128 includes a plurality of extensions extending radially outward from the wall relative to the axis R. The extensions are disposed outside of the cavity 110. The extensions extend circumferentially around the wall relative to the axis R, i.e., completely around the wall. That is, the wall has a larger diameter than the opening 122 at each extension. Each extension may extend radially outward from the wall relative to the axis R by the same or different amounts. The extensions may extend radially outward from the wall relative to the axis R by any suitable amount.

[0049] The cover 132 covers the body 128. For example, the cover 132 completely surrounds the body 128 abutting the housing 102. The cover 132 can compress the extension radially inward relative to the axis R and / or axially toward the housing 102, which can help seal the opening 122.

[0050] Additionally, a seal, such as an o-ring or the like, may extend circumferentially around the body 128. The seal may be pressed against the body 128 and the housing 102 by the cover 132 to further help seal the opening 122. That is, the cover 132, the seal, and the body 128 seal the opening 122 around the cable 124. In other words, the cable gland 126 prevents fluid communication between the cavity 110 and the environment surrounding the housing 102 via the opening 122. The cable gland 126, i.e., the body 128 and the cover 132 may be any suitable material, such as rubber, plastic, etc.

[0051] The twelfth axial portion 112l may extend from the eleventh locator surface 114k to the twelfth locator surface 114l. The twelfth locator surface 114l may extend radially outwardly from the twelfth axial portion 112l to the thirteenth axial portion 112m relative to the axis A. The twelfth locator surface 114l axially constrains the idler bearing 172 in the second direction d2.

[0052] The thirteenth axial portion 112m may extend from the twelfth locator surface 114l to the thirteenth locator surface 114m. The thirteenth locator surface 114m may extend radially outwardly from the thirteenth axial portion 112m to the fourteenth axial portion 112n relative to the axis A. The thirteenth locator surface 114m axially constrains the outer idler retainer 176 in the second direction d2. The fourteenth axial portion 112n may radially constrain the outer idler retainer 176.

[0053] The fourteenth axial portion 112n can extend from the thirteenth locator surface 114m to the fourteenth locator surface 114n. The fourteenth locator surface 114n can extend radially outward from the fourteenth axial portion 112n to the fifteenth axial portion 112o relative to the axis A. The fourteenth axial portion 112n can be designed, i.e., sized and shaped to receive the outer idler retainer 176. That is, the fourteenth axial portion 112n can extend along the axis A so that the outer idler retainer 176 can be inserted between the thirteenth locator surface 114m and the fourteenth locator surface 114n defining the groove 175 during assembly of the rotary actuator 100. The fourteenth locator surface 114n axially constrains the outer idler retainer 176 in the first direction d1.

[0054] The fifteenth axial portion 112o may extend from the fourteenth locator surface 114n to the fifteenth locator surface 114o. The fifteenth locator surface 114o may extend radially outwardly from the fifteenth axial portion 112o to the sixteenth axial portion 112p relative to the axis A. The fifteenth locator surface 114o axially constrains the second seal 120b in the second direction d2. The sixteenth axial portion 112p may extend from the fifteenth locator surface 114o to the second end 106 of the housing 102. The sixteenth axial portion 112p radially constrains the second seal 120b.

[0055] Now go to Figure 3 The rotary actuator 100 includes an output shaft 134 arranged coaxially with the axis A. The output shaft 134 may be any suitable material to withstand the forces and environmental effects of being submerged in water, such as salt water. For example, the output shaft 134 may be a non-corrosive metal, such as stainless steel.

[0056] The output shaft 134 extends outward through the first end 104 of the housing 102. That is, the output shaft 134 is partially disposed within the cavity 110. The output shaft 134 includes a first end 136 and a second end 138 spaced apart from the first end 136 along the axis A. The output shaft 134 is stepped in cross-section and includes a first portion 140, a second portion 144, and a sealing portion 142, each extending circumferentially around the axis A. The first portion 140 extends from the first end 136 to the sealing portion 142, and the second portion 144 extends from the sealing portion 142 to the second end 138. The first portion 140 may be connected to a component of a ship stabilizer system, such as a fin, a blade, etc. In such an example, the rotary actuator 100 may be actuated to adjust the angular position of the fin to generate pressure that disturbs waves around the ship, thereby stabilizing the ship during operation on the waterway.

[0057] The sealing portion 142 is disposed radially outwardly of the first portion 140 relative to the axis A. The sealing portion 142 extends from the first portion 140 to the second portion 144 along the axis A. The sealing portion 142 may be designed, ie, sized and shaped, to engage the first seal 120a.

[0058] The second portion 144 is disposed radially outside the sealing portion 142 relative to the axis A. The second portion 144 may include a groove 146 disposed between the second end 138 of the output shaft 134 and the first portion 140. The groove 146 may extend circumferentially around the axis A, i.e., completely around the second portion 144. The groove 146 may be axially aligned with the third axial portion 112c. The groove 146 may be designed to receive the inner retainer 118. That is, the groove 146 may extend along the axis A so that the inner retainer 118 may be inserted into the groove 146 during assembly of the rotary actuator 100. The groove 146 axially constrains the inner retainer 118 in the first direction d1 and the second direction d2, and may radially constrain the inner retainer 118.

[0059] The second portion 144 includes a recess 148 extending from the second end 138 of the output shaft 134 toward the sealing portion 142 of the output shaft 134. The recess 148 is axially spaced from the first portion 140. The recess 148 extends circumferentially around the axis A. The recess 148 may be threaded, i.e., include threads, to facilitate non-rotatable attachment of the output gear 232 of the gearbox 200 to the output shaft 134.

[0060] The output shaft 134 is rotatably supported by an output bearing 150. The output bearing 150 is coaxially arranged with the axis A. The output bearing 150 may extend annularly around the axis A. The output bearing 150 may be positioned between the second end 138 of the output shaft 134 and the recess 146. The output bearing 150 may be any suitable type of bearing, including but not limited to a single row ball bearing, a double row ball bearing, an angular contact ball bearing, or two single row ball bearings, as shown. The output bearing 150 may be press-fitted onto the outer surface of the second portion 144 of the output shaft 134. The inner retainer 118 may axially constrain the output bearing 150 in the second direction d2. The output bearing 150 may have a sliding fit connection or a press fit connection with the fourth axial portion 112d.

[0061] The outer retainer 116 engages the housing 102 and the output bearing 150. The outer retainer 116 and the inner retainer 118 may be any suitable type of retainer, such as a snap ring. The outer retainer 116 and the inner retainer 118 may be the same type or different types of retainers.

[0062] As explained above, the outer retainer 116 and the inner retainer 118 axially constrain the output shaft 134 in the second direction d2 within the cavity 110, and specifically, constrain the output bearing 150. In order to axially constrain the output bearing 150, the housing 102 and the output shaft 134 may be crimped after the inner retainer 116 and the outer retainer 118 are installed. Crimping the housing 102 and the output shaft 134 minimizes the axial clearance between the outer retainer 116 and the second locator surface 114b and the third locator surface 114c and the axial clearance between the groove 146 and the inner retainer 118, which can minimize the stacking tolerance of the components associated with the output shaft 134 relative to the housing 102. For example, the outer retainer 116 can be compressed between the second locator surface 114b and the third locator surface 114c, and the inner retainer 118 can be compressed between the walls of the groove 146. Axially controlling the output bearing 150 can reduce the axial clearance between the output shaft 134 and the gearbox 200.

[0063] The first seal 120a of the rotary actuator 100 is disposed at the first end 104 of the housing 102 and covers the first end 104. That is, the first seal 120a extends radially from the output shaft 134 to the housing 102. The first seal 120a can be press-fitted into the housing 102 and onto the output shaft 134 so that the output shaft 134 rotates sealed relative to the housing 102. The first seal 120a prevents fluid communication between the cavity 110 and the environment around the housing 102 through the first end 104. The first seal 120a can be any suitable type of seal. The first seal 120a can include one or more retaining members, such as radial springs, which help maintain contact between the first seal 120a and the output shaft 134 and / or between the first seal 120a and the housing 102. The first seal 120a can be any suitable material or combination of materials, such as rubber, metal, etc.

[0064] The rotary actuator 100 may include grease or the like disposed in the cavity 110 adjacent to the first seal 120 a. The grease may be any suitable type of water-resistant grease. The grease may reduce the likelihood of water intrusion into the cavity 110 .

[0065] Now go to Figure 4 , the gearbox 200 may be a strain wave gearbox 200 , as shown in the drawings and discussed herein. However, the gearbox 200 may be any other suitable type of gearbox, such as a planetary gearbox, etc.

[0066] The strain wave gearbox 200 is disposed in the cavity 110. The strain wave gearbox 200 is engaged with the output shaft 134. Additionally, the strain wave gearbox 200 is engaged with the drive system 300. Specifically, the strain wave gearbox 200 is configured to receive torque from the drive system 300. Additionally, the strain wave gearbox 200 is configured to increase the torque, for example via a gear ratio, and output the increased torque to the output shaft 134. The strain wave gearbox 200 may be configured to have a specified gear ratio, for example, 66 to 1. The specified gear ratio may be determined empirically, for example, based on a test that allows determination of a gear ratio that can increase a torque having a value within an input range, for example, corresponding to the characteristics of the electric motor, to a torque having an output range, for example, a value within an output range specified by the manufacturer of the rotary actuator 100.

[0067] The strain wave gearbox 200 includes a fixed gear 202 that is non-rotatably connected to the housing 102. The fixed gear 202 includes an internal tooth system 208 on an inner surface 204. The internal tooth system 208 includes a plurality of teeth extending radially inwardly from the inner surface 204 relative to the axis A. Each tooth may extend from a first axial side to a second axial side of the fixed gear 202. The teeth in the internal tooth system 208 may be substantially identical to each other.

[0068] The fixed gear 202 includes an outer surface 210 extending from a first axial side to a second axial side of the fixed gear 202. The outer surface 210 extends circumferentially around the inner surface 204. That is, the outer surface 210 is located radially outside the inner surface 204 relative to the axis A. The fixed gear 202 includes an outer tooth system 212 on the outer surface 210. The outer tooth system 212 includes a plurality of teeth and ridges spaced circumferentially around the axis A. The teeth and ridges may extend from the second axial side toward the first axial side. For example, the teeth and ridges may be spaced apart from the first axial side.

[0069] The fixed gear 202 can be connected to the housing 102 in a non-rotatable manner. For example, the external tooth system 212 can engage the sixth locator surface 114f and / or the seventh axial portion 112g. During assembly, the fixed gear 202 can be inserted into the cavity 110 through the second end 106 until the fixed gear 202 abuts the sixth locator surface 114f. The teeth and / or ridges can be designed so that the fixed gear 202 deforms the sixth locator surface 114f and / or the seventh axial portion 112g. In this case, the material of the sixth locator surface 114f and / or the seventh axial portion 112g can be pressed between the teeth and ridges of the fixed gear 202, which prevents the fixed gear 202 from moving axially or radially relative to the housing 102.

[0070] The strain wave gearbox 200 includes a drive gear 214. The drive gear 214 is configured to transmit torque from the drive system 300 to the wave generator 220 (as discussed further below). The drive gear 214 includes a body 216 extending annularly about an axis A. The body 216 defines a cavity 218 arranged coaxially with the axis A. The cavity 218 is designed, sized and shaped to receive components of the drive system 300 (as discussed below). The drive gear 214 includes one or more blades extending radially outward from the body 216. The drive gear 214 can be any suitable material, such as a metal, to receive and transmit torque from the drive system 300.

[0071] The strain wave gearbox 200 includes a wave generator 220. The wave generator 220 is arranged coaxially with the axis A. The wave generator 220 is circumferentially surrounded by the fixed gear 202 relative to the axis A. The wave generator 220 includes a bearing 222. The bearing 222 includes an inner ring 190, an outer ring 192, a cage 201 between the inner ring and the outer ring, and a plurality of rollers or balls 194 supported in the cage 201 and circumferentially spaced from each other. The inner ring 190 has a non-circular, for example, elliptical profile. The outer ring 192 is configured to be flexible relative to the inner ring 190 so that the outer ring 192 is adapted to the non-circular shape of the inner ring 190.

[0072] The wave generator 220 includes a coupling 224 that is non-rotatably connected to the inner ring 190, for example, via fasteners. The coupling 224 defines an opening 226 coaxially aligned with the axis A. The opening 226 extends axially through the coupling 224. The opening 226 is designed, i.e., sized and shaped to receive the drive gear 214. The coupling 224 is configured to transmit torque to the inner ring of the bearing 222 while reducing or preventing torque clearance. The coupling 224 can be referred to as an Oldham coupling. The coupling 224 can be any suitable material, such as plastic, rubber, etc.

[0073] The wave generator 220 includes a flexible ring 228 extending annularly about the axis A. The flexible ring 228 extends circumferentially about the outer ring 192 of the bearing 222. It is further stated that the flexible ring 228 is disposed radially outwardly relative to the outer ring 192. The flexible ring 228 can be configured to fit the shape of the outer ring 192. The flexible ring 228 can be frictionally engaged with the outer ring 192. For example, the flexible ring 228 can be rotated by the outer ring 192 based on the friction therebetween. The flexible ring 228 can be any suitable material, such as plastic, rubber, etc.

[0074] The flexible ring 228 comprises an external tooth system 230. The external tooth system 230 comprises a plurality of teeth extending radially outward from the flexible ring 228. The teeth are circumferentially spaced from one another around the axis A. The teeth may extend from one axial side of the flexible ring 228 to the other axial side. The external tooth system 230 of the flexible ring 228 engages with the internal tooth system 208 of the fixed gear 202. The teeth of the internal tooth system 208 may extend partially on the flexible ring 228 relative to the axis A. The number of teeth of the external tooth system 230 corresponds to the number of teeth of the internal tooth system 208. Thus, the flexible ring 228 maintains, i.e. maintains, an angular position relative to the fixed gear 202.

[0075] The wave generator 220 may include a cover 196 extending annularly about the axis A. The cover 196 may circumferentially surround the coupling 224 relative to the axis A. The cover 196 may be designed to cover the cage and the rollers, for example to prevent debris from entering the bearing 222. The cover 196 may be non-rotatably connected to the housing 102, for example, via a press-fit connection. For example, the cover 196 may abut the seventh axial portion 112g. By extending radially to the seventh axial portion 112g, the cover 196 may axially constrain the bearing 222 in the first direction d1. The cover 196 may be any suitable material, such as a metal.

[0076] The strain wave gearbox 200 includes an output gear 232. The output gear 232 includes an inner surface extending circumferentially around the axis A. The inner surface defines a protrusion 234. The protrusion 234 is disposed within the recess 148 of the output shaft 134. The protrusion 234 has a diameter corresponding to the diameter of the recess 148. Specifically, the recess 148 is designed to receive a fastener, such as a bolt 188. The bolt 188 can threadably engage the recess 148 to connect the strain wave gearbox 200, that is, the output gear 232, to the output shaft 134 in a non-rotatable manner.

[0077] The output gear 232 includes a first axial side portion 236 and a second axial side portion 238. The first axial side portion 236 abuts the second end portion 138 of the output shaft 134. The bearing 222 may abut the second axial side portion 238. That is, the output gear 232 is axially disposed between the output shaft 134 and the wave generator 220.

[0078] The output gear 232 includes an outer surface extending circumferentially around the inner surface. The outer surface is radially spaced from the housing 102, for example to allow the output gear 232 to rotate relative to the housing 102. For example, the outer surface can be located radially inside the fifth axial portion 112e. The output gear 232 includes an extension 240 extending axially from the second axial side 238 at the outer surface. The extension 240 extends in the first direction d1, i.e., toward the drive system 300. The extension 240 extends circumferentially around the axis A.

[0079] The extension includes an internal tooth system 242 having a plurality of teeth extending radially inwardly toward the axis A. The internal tooth system 242 is configured to engage the external tooth system 230 of the flexible ring 228. The internal tooth system 242 may be spaced apart from the internal tooth system 208 of the fixed gear 202 relative to the axis A. That is, the internal tooth system 242 may extend partially over the flexible ring 228 relative to the axis A. The number of teeth of the internal tooth system 242 is different from the number of teeth of the external tooth system 230. The difference between the number of teeth in the corresponding tooth systems 242, 230 results in a slight pivoting of the output gear 232 relative to the housing 102. The strain wave gearbox 200 may be configured such that the output gear 232 rotates in the same direction as the electric motor 302.

[0080] The rotary actuator 100 may include any suitable number of spacers arranged to axially control the positions of various components within the rotary actuator 100. For example, Figure 3 As shown, the rotary actuator 100 may include a spacer 201 disposed between the output bearing 150 and the strain wave gearbox 200, such as the output gear 232. The spacer may be any suitable material, such as metal. The spacer may have any suitable thickness, such as determined along the axis A.

[0081] Now go to Figure 5 The drive system 300 is engaged with the gearbox 200, as discussed further below. The drive system 300 is disposed in the cavity 110. The gearbox 200 is disposed between the output shaft 134 and the drive system 300.

[0082] The drive system 300 includes an electric motor 302. The electric motor 302 includes a fixed stator 304 and a rotatable rotor 306. The stator 304 is non-rotatably connected to the housing 102, such as via a press-fit connection, an adhesive, or the like.

[0083] Power is provided to the windings of the stator 304, thereby generating a magnetic force that exerts torque on the rotor 306. The electric motor 302 may be, for example, an AC electric motor, such as a permanent magnet synchronous motor, etc. In the case of a synchronous AC electric motor, the rotational speed of the rotor 306 is adjusted by adjusting the frequency of the current using an inverter. In the case of other types of electric motors, a speed or position feedback signal may be required.

[0084] The rotor shaft 308 includes a first end 310 and a second end 312 spaced apart from the first end 310 along the axis A. The rotor shaft 308 may extend from the first end 310 to the second end 312. The rotor shaft 308 includes a first portion 314 extending from the first end 310 to a first shoulder 316. The first shoulder 316 extends radially outward from the first portion 314. The first portion 314 may be designed to engage the gearbox 200. For example, the first portion 314 may be disposed in a cavity 218 of a drive gear 214. In such an example, the first portion 314 may be connected to the drive gear 214 in a non-rotatable manner such that rotation of the rotor shaft 308 causes the drive gear 214 to rotate. The first shoulder 316 may abut the drive gear 214, which may axially constrain the rotor shaft 308 in the second direction d2.

[0085] The rotor shaft 308 includes a second portion 318 extending from the first shoulder 316 to the second shoulder 320. The second portion 318 is disposed radially outward from the first portion 314. The second shoulder 320 extends radially outward from the second portion 318.

[0086] The rotor shaft 308 includes a third portion 322 extending from the second shoulder 320 to the third shoulder 324. The third portion 322 is disposed radially outward from the second portion 318. The third shoulder 324 extends radially outward from the third portion 322. The rotor 306 abuts the third shoulder 324. That is, the third shoulder 324 axially constrains the rotor 306 in the first direction d1. At least a portion of the third portion 322 is disposed within the rotor 306.

[0087] The rotor shaft 308 includes a fourth portion 326 extending from the third shoulder 324 to a fourth shoulder 328. The fourth portion 326 is disposed radially outward from the third portion 322. The fourth shoulder 328 extends radially inward from the fourth portion 326.

[0088] The rotor shaft 308 includes a fifth portion 330 extending from the fourth shoulder 328 to the fifth shoulder 332. The fifth portion 330 is disposed radially inward from the fourth portion 326. The fifth shoulder 332 extends radially inward from the fifth portion 330. The fifth portion 330 may be designed to create an axial gap between the fourth portion 326 of the rotor shaft 308 and the second drive bearing 350, for example to allow the inner ring of the second drive bearing 350 to rotate relative to the outer ring.

[0089] The rotor shaft 308 includes a sixth portion 334 extending from the fifth shoulder 332 to the sixth shoulder 336. The sixth portion 334 is disposed radially inward from the fifth portion 330. The sixth shoulder 336 extends radially inward from the sixth portion 334. The sixth portion 334 may be designed, ie, sized and shaped, to receive the second drive bearing 350.

[0090] The rotor shaft 308 includes a seventh portion 338 extending from the sixth shoulder 336 to the second end 312 of the rotor shaft 308. The seventh portion 338 is disposed radially inward of the sixth portion 334.

[0091] The drive system 300 comprises a sleeve 370 arranged on the rotor shaft 308. The sleeve 370 may be non-rotatably connected to the rotor shaft 308, for example via a press-fit connection. The sleeve 370 comprises a recess designed to receive the first encoder magnet 368a.

[0092] The first encoder magnet 368a is connected to the sleeve 370 in a non-rotatable manner. For example, the first encoder magnet 368a can be connected to the sleeve 370 in a recess, such as via a press-fit connection, an adhesive, etc. The first encoder magnet 368a has diametric polarity, i.e., magnetic poles that are diametrically spaced from each other on the first encoder magnet 368a. The first encoder magnet 368a can be arranged coaxially with the axis A. The sleeve 370 can be brass or any other suitable material that does not produce magnetic interference.

[0093] The drive system 300 includes a first drive bearing 340 and a first drive bearing housing 342. The rotor shaft 308 is rotatably supported by the first drive bearing 340. The first drive bearing 340 is non-rotatably connected to the second portion 318 of the rotor shaft 308. For example, the first drive bearing 340 can be press-fit onto the rotor shaft 308. The first drive bearing 340 abuts the second shoulder 320. That is, the second shoulder 320 axially constrains the first drive bearing 340 in the first direction d1. The first drive bearing 340 can be any suitable type of bearing, such as a single row roller bearing.

[0094] The first drive bearing housing 342 houses the first drive bearing 340. For example, the first drive bearing housing 342 can extend annularly about the axis A. The first drive bearing housing 342 defines a first housing cavity 344. The first housing cavity 344 extends circumferentially about the axis A. Additionally, the first housing cavity 344 can extend from a first axial side to a second axial side of the first drive bearing housing 342. The first drive bearing 340 is disposed within the first housing cavity 344. The first drive bearing 340 can be slidably fitted or press-fitted into the first housing cavity 344, for example to allow rotation of the rotor shaft 308 relative to the first drive bearing housing 342. The first drive bearing housing 342 can be any suitable material, such as plastic, aluminum, etc.

[0095] The first drive bearing housing 342 includes an outer surface 346 that extends circumferentially about the axis A. The outer surface 346 is radially spaced apart from the first housing cavity 344. The outer surface 346 is designed to engage the seventh axial portion 112g of the wall 108. Specifically, the outer surface 346 of the first drive bearing housing 342 is non-rotatably connected to the seventh axial portion 112g, for example, via a press-fit connection.

[0096] The drive system 300 includes a second drive bearing 350 and a second drive bearing housing 352. The rotor shaft 308 is rotatably supported by the second drive bearing 350. The second drive bearing 350 is non-rotatably connected to the sixth portion 334 of the rotor shaft 308. For example, the second drive bearing 350 can be press-fitted onto the rotor shaft 308. The second drive bearing 350 engages the fifth shoulder 332. That is, the fifth shoulder 332 axially constrains the second drive bearing 350 in the second direction d2. The second drive bearing 350 can be substantially the same as the first drive bearing 340.

[0097] The second drive bearing housing 352 accommodates the second drive bearing 350. For example, the second drive bearing housing 352 may extend annularly around the axis A. The second drive bearing housing 352 defines a second drive bearing housing cavity 354. The second drive bearing housing cavity 354 extends circumferentially around the axis A. The second drive bearing housing cavity 354 extends from a first axial side portion to a second axial side portion of the second drive bearing housing 352. The second drive bearing 350 is arranged in the second drive bearing housing cavity 354. The second drive bearing housing 352 may be any suitable material, such as plastic, aluminum, etc. The second drive bearing housing 352 may include a shoulder 356 disposed in the second drive bearing housing cavity 354 and extending radially inward, i.e., toward the axis A. The second drive bearing 350 may engage with the shoulder 356. That is, the shoulder 356 may axially constrain the second drive bearing housing 352 in the second direction d2. The second drive bearing 350 may be slidably fitted or press-fitted into the second drive bearing housing cavity 354 and facilitate the rotation of the rotor shaft 308 relative to the second drive bearing housing 352.

[0098] The second drive bearing housing 352 includes an outer surface 358 extending circumferentially around the axis A. The outer surface 358 is radially spaced apart from the second drive bearing housing cavity 354. The outer surface 358 includes a first portion 360 and a second portion 362. The first portion 360 extends from the first axial side to the second portion 362, and the second portion 362 extends from the first portion 360 toward the second axial side. The first portion 360 of the outer surface 358 is disposed radially outside the second portion 362. The first portion 360 engages the tenth axial portion 112j. For example, the first portion 360 may be non-rotatably connected to the tenth axial portion 112j, for example, via a press-fit connection. The transition between the first portion 360 and the second portion 362 of the second drive bearing housing 352 may be axially aligned with the tenth locator surface 114j.

[0099] Second bearing housing 352 may include a groove extending axially from the first axial side toward second portion 362. The groove may extend circumferentially about axis A. The groove may be disposed radially between second portion 362 and second drive bearing housing cavity 354. The groove may reduce compressive forces on second drive bearing 350, which may help allow rotor shaft 308 to rotate relative to second bearing housing 352.

[0100] The second portion 362 is radially spaced from the eleventh axial portion 112k. The second portion 362 may include a groove 364 extending circumferentially about the axis A. The groove 364 may extend radially inward from the second portion 362 toward the second drive bearing housing cavity 354. The groove 364 may be axially spaced from the first portion 360. The groove 364 may extend toward the second drive bearing housing cavity 354 by any suitable amount.

[0101] The second portion 362 may include an opening extending axially through a first axial side and a second axial side of the second bearing housing 352. The opening may be designed, sized and shaped to receive one or more wires from the electric motor 302. For example, wires from the electric motor 302 may be routed through the opening to connect the motor 302 to the circuit board(s) 412. The second bearing housing 352 may include a grommet designed to seal around the opening of the wires. The grommet may be any suitable material, such as rubber.

[0102] The first encoder magnet 368a is disposed within the second drive bearing housing cavity 354. The second drive bearing housing cavity 354 can be designed, i.e., sized and shaped, such that the second drive bearing housing 352 does not generate magnetic interference. That is, the second drive bearing housing 352 can extend annularly about the axis A such that the inner surface of the second drive bearing housing 352 is radially spaced from the first encoder magnet 368a by at least a distance that prevents the second drive bearing housing 352 from magnetically interfering with a first sensor 414a arranged to detect the angular position of the first encoder magnet 368a. The first sensor 414a can be described as a rotational position sensor.

[0103] The drive system 300 includes a shield 366 connected to the second drive bearing housing 352. The shield 366 can be connected to the second drive bearing housing 352 in any suitable manner, such as via fasteners, adhesives, welding, etc. The shield 366 is disposed on an axial side of the second drive bearing housing 352 facing away from the gearbox 200. The shield 366 covers the second drive bearing accommodating cavity 354 at the axial side. The shield 366 and the second drive bearing housing 352 can prevent fluid communication through the cavity 110, for example, fluid communication from one end 104, 106 to the other end 104, 106.

[0104] The shield 366 can be any suitable material that does not generate magnetic interference, such as plastic, metal, etc. The shield 366 can have a thickness determined along the axis A so that the thickness can limit deformation of the shield 366, such as due to thermal effects and / or vibration effects, while not preventing the first sensor 414a from detecting the first encoder magnet 368a.

[0105] The resilient member 152 is axially disposed between the cover 196 of the wave generator 220 and the first drive bearing housing 342. The resilient member 152 is designed, sized and shaped, to axially control, i.e., minimize, stacking tolerances of components associated with the drive system 300 relative to the housing 102. Axially controlling the drive system 300 can increase the likelihood that the first encoder magnet 368a remains within a predetermined range of the first sensor 414a. The predetermined range can be specified by the manufacturer of the sensor, for example, based on empirical testing to determine that the sensor 414 output meets a specified range of measurement accuracy and / or precision.

[0106] The elastic member 152 is engaged with the drive system 300 to bias the drive system 300 in the first direction d1. The elastic member 152 may also be engaged with the strain wave gearbox 200 and / or the housing 102 to bias the drive system 300 in the first direction d1. The elastic member may be of any suitable type, such as a compression spring, an arc spring, a wave spring, etc.

[0107] Now go to Figure 6 The rotation controller 400 is disposed between the driving system 300 and the second end 106 of the housing 102. That is, the rotation controller 400 is disposed in the cavity 110. The rotation controller 400 includes a sensor 414 and a plurality of circuit boards 412.

[0108] The first circuit board 412a includes a first sensor 414a. The first sensor 414a is axially aligned with the first encoder magnet 368a. The first sensor 414a is an angular position sensor. Specifically, the first sensor 414a is configured to detect the angular position of the first encoder magnet 368a (arranged on the sleeve 370 of the rotor shaft 308) relative to the axis A. The first sensor 414a can be any suitable type of angular position sensor. For example, the first sensor 414a can be a Hall effect sensor configured to output a unique angular position within a range of 360° rotation around the axis A. In such an example, the Hall effect sensor can, for example, determine the angular position of the first encoder magnet 368a based on the position of the detection pole relative to the axis A according to known techniques.

[0109] The second circuit board 412 b may be referred to as a power electronics circuit board. That is, the second circuit board 412 b may include one or more devices, such as semiconductor switching devices such as diodes, thyristors, power transistors, etc., current converter devices, etc., for controlling and converting the power provided to the rotation controller 400, which allows the computer 416 to control the electric motor 302.

[0110] The third circuit board 412c includes a second sensor 414b. The second sensor 414b can be substantially the same as the first sensor 414a and can also be described as a rotational position sensor. The second sensor 414b can be configured to measure the absolute position of the idler shaft 154 within a 360-degree range. The third circuit board 412c can have a smaller surface area than the first circuit board 412a and / or the second circuit board 412b.

[0111] A plurality of supports 402 supports a circuit board 412 within the cavity 110. Each support 402 includes a first end 404 that engages the second drive bearing housing 352 and a second end 406 that is axially spaced from the first end 404. Each support 402 is mounted to the second drive bearing housing 352, for example, via a press-fit connection. For example, the second drive bearing 350 may have a plurality of recesses (not shown) that are circumferentially spaced from each other about the axis A, and each support 402 may be press-fit into a corresponding recess. The supports 402 may be any suitable material, such as plastic.

[0112] Each support 402 may include a plurality of loading surfaces 408 spaced apart from one another along axis A. Each loading surface 408 may be configured to axially support a corresponding circuit board 412, as discussed further below. Each support 402 may include the same number of loading surfaces 408 as circuit boards 412. Each loading surface 408 may extend radially relative to axis A. Each support 402 may include a plurality of fingers 410 spaced apart from one another axially along axis A. Each finger 410 may extend obliquely toward axis A. For example, each finger 410 may extend radially inward and axially toward a corresponding loading surface 408. Each finger 410 is configured to axially constrain a corresponding circuit board 412 relative to a corresponding loading surface 408. The support 402 is configured to position the first sensor 414a within a predetermined range of the first encoder magnet 368a and to position the second sensor 414b within a predetermined range of the second encoder magnet 368b.

[0113] For example, each support member 402 may include a first loading surface 408a spaced apart from the first end 404 and a first finger 410a spaced apart from the first loading surface 408a in the first direction d1. The first finger 410a extends toward the first loading surface 408a along the second direction d2 and extends radially inward toward the axis A. The first circuit board 412a may be disposed between the first loading surface 408a and the first finger 410a. Specifically, the first finger 410a may bias the first circuit board 412a against the first loading surface 408a. For example, the first finger 410a may be designed to be elastically deformed so that the first circuit board 412a may be inserted between the first loading surface 408a and the first finger 410a. After installation, the first finger 410a may rebound in the second direction d2 and axially bias the first circuit board 412a to contact the first loading surface 408a.

[0114] The first loading surface 408a is spaced from the first end 404 such that the first sensor 414a is disposed within a predetermined range of the first encoder magnet 368a. As discussed herein, components of the rotary actuator 100 are axially constrained to maintain the first sensor 414a within a predetermined range of the first encoder magnet 368a.

[0115] Each support member 402 may include a second loading surface 408b axially spaced from the first finger 410a in the first direction d1. Additionally, each support member 402 may include a second finger 410b axially spaced from the second loading surface 408b in the first direction d1. The second finger 410b may extend toward the second loading surface 408b in the second direction d2 and extend radially inward toward the axis A. The second circuit board 412b may be disposed between the second loading surface 408b and the second finger 410b. The second finger 410b may be axially spaced from the second circuit board 412b. For example, the second finger 410b may be an assembly aid that prevents the second circuit board 412b from being inserted between the second loading surface 408b and the second finger 410b when a component of the first circuit board 412a is not properly seated with a mating component of the second circuit board 412b.

[0116] Each support 402 may include a third loading surface 408c axially spaced from the second finger 410b in the first direction d1. Additionally, each support 402 may include a third finger 410c axially spaced from the third loading surface 408c in the first direction d1. The third finger 410c may be disposed at the second end 406. The third finger 410c may extend toward the third loading surface 408c in the second direction d2 and extend radially inward toward the axis A. The third circuit board 412c may be disposed between the third loading surface 408c and the third finger 410c. Specifically, the third finger 410c may bias the third circuit board 412c against the third loading surface 408c. The third finger 410c may be substantially the same as the first finger 410a. The third loading surface 408c may be spaced from the first end 404 so that the second sensor 414b is disposed within a predetermined range of the second encoder magnet 368b.

[0117] The eleventh axial portion 112k of the cavity 110 accommodating the rotation controller 400 may be potted, ie filled with a potting compound 182 (see Figure 1). The potting compound 182 can be any suitable material, such as epoxy, polyurethane, silicone, etc. For example, the potting compound 182 can cover the rotation controller 400 and adhesively seal relative to the inner surface 184 of the wall 108 of the housing 102. By covering the rotation controller 400, the potting compound 182 can protect the rotation controller 400, and specifically protect the circuit board 412 and its components from debris and / or fluids entering the cavity 110 in the presence. Additionally, the potting compound 182 can provide a means of vibration resistance for the rotation controller 400, and can also provide an enhanced thermal path between the rotation controller 400 and the housing 102 to better dissipate heat. Due to the adhesive properties of the potting compound 182, filling the groove 364 and surrounding area of ​​the second drive bearing housing 352 with the potting compound prevents axial displacement of the second drive bearing housing 352 relative to the housing 102. This axial fixation prevents axial displacement of the second drive bearing 350 , which resides within the second drive bearing housing 352 and is fixed to the rotor shaft 308 , and the first drive bearing 340 , which is fixed to the rotor shaft 308 .

[0118] The potting compound 182 is radially spaced from the second encoder magnet 368b. That is, the potting compound 182 defines a recess 198 within which the second encoder magnet 368b can rotate freely. The recess 198 can be formed during installation of the potting compound 182 into the cavity 110. The potting compound 182 can be axially spaced from the second encoder magnet 368b.

[0119] Reference Figure 2 , it should be noted that the rotation controller 400 and the surrounding potting compound 182 reside within an eleventh axial segment or portion 112k defined by a first diameter d1 of the inner surface 184. The tenth axial segment 112j directly adjacent to the first side of the eleventh axial segment or portion 112k is defined by a second diameter d2 of the inner surface 184, and the twelfth axial segment or segment 112l directly adjacent to the second side of the eleventh axial segment 112k is defined by a third diameter d3 of the inner surface. The first diameter d1 is greater than the second diameter d2 and the third diameter d3. In other words, the inner surface 184 residing within the eleventh axial segment 112k extends radially outward relative to the axis A from adjacent inner surfaces residing within the respective tenth axial segment 112j and the twelfth axial segment 112l.

[0120] Now go to Figure 7 , the rotary actuator 100 may include an idler shaft 154. The rotary controller 400 may be disposed between the idler shaft 154 and the drive system 300. The idler shaft 154 is disposed coaxially with the axis A. The idler shaft 154 extends outward through the second end 104 of the cavity 110. That is, the idler shaft 154 is partially disposed within the cavity 110.

[0121] The idler shaft 154 includes a first end 156 and a second end 158 spaced apart from the first end 156 along the axis A. The idler shaft 154 also includes a first portion 160, a second portion 162, a sealing portion 164, and a third portion 166. The first portion 160 extends from the first end 156 to the second portion 162. The first portion 160 extends circumferentially around the axis A. A sleeve 178 is arranged on the first portion 160 of the idler shaft 154. The sleeve 178 can be connected to the idler shaft 154 in a non-rotatable manner, for example, via a press-fit connection. The sleeve 178 can extend farther along the axis A than the first portion 160. For example, the sleeve 178 can extend from the second portion 162 beyond the first end 156 of the idler shaft 154 in the second direction d2. The sleeve 178 can be substantially the same as the sleeve 370.

[0122] The sleeve 178 of the idler shaft 154 includes a second encoder magnet 368b. The second encoder magnet 368b is substantially identical to the first encoder magnet 368a. The second encoder magnet 368b can be arranged coaxially with the axis A. The second encoder magnet 368b is non-rotatably connected to the sleeve 178, for example, in a manner substantially the same as discussed above regarding the first encoder magnet 368a being non-rotatably connected to the sleeve 370. As discussed below, the idler shaft 154 is axially constrained to keep the second encoder magnet 368b within a predetermined range of the second sensor 414b.

[0123] The second portion 162 extends from the first portion 160 to the sealing portion 164. The second portion 162 extends circumferentially around the axis A. The second portion 162 has a larger diameter than the first portion 160. That is, the second portion 162 extends radially outward from the first portion 160. The second portion 162 may include two grooves 168 axially spaced from each other. The first groove 168a may be disposed closer to the first portion 160 than the second groove 168b. The second groove 168b may be disposed closer to the sealing portion 164 than the first groove 168a. The groove 168 may extend circumferentially around the axis A, i.e., completely around the second portion 162.

[0124] The sealing portion 164 is disposed radially inwardly of the second portion 162 relative to the axis A. The sealing portion 164 extends from the second portion 162 to the third portion 166 along the axis A. The sealing portion 164 may be designed, ie, sized and shaped, to engage the second seal 120b.

[0125] The third portion 166 extends from the sealing portion 164 to the second end 158. The third portion 166 extends circumferentially about the axis A. The third portion 166 can extend radially inward from the sealing portion 164. The third portion 166 can have a larger diameter than the first portion 160. The third portion 166 can include a blind recess 170 extending axially from the second end 158 and terminating in the sealing portion 164. The recess 170 can extend circumferentially about the axis A.

[0126] An idler bearing 172 rotatably supports the idler shaft 154 in the cavity 110. The idler bearing 172 is coaxially arranged with the axis A. The idler bearing 172 may extend annularly about the axis A. The idler bearing 172 may be positioned between the grooves 168. The idler bearing 172 may be any suitable type of bearing, such as a deep groove ball bearing. The idler bearing 172 may be substantially the same as the output bearing 150. The idler bearing 172 may be press-fitted onto the second portion 162. The idler bearing 172 may have a slip fit connection or a press fit connection with the thirteenth axial portion 112m to facilitate rotation of the idler shaft 154 relative to the housing 102.

[0127] The inner idler retainer 174 is engaged with the idler shaft 154 and the idler bearing 172. The inner idler retainer 174 axially constrains the idler bearing 172 in the first direction d1 and the second direction d2. The inner idler retainer 174 can be any suitable type of retainer, such as a snap ring. Each inner idler retainer 174 is disposed in a corresponding groove 168.

[0128] The outer idler retainer 176 engages within the groove 175 of the housing 102 and the idler bearing 172. The outer idler retainer 176 can be any suitable type of retainer, such as a snap ring. The outer idler retainer 176 and the inner idler retainer 174 can be the same type or different types of retainers.

[0129] The grooves 168, 175 can be crimped to axially constrain the idler bearing 172, as previously discussed with respect to the output bearing 150. Additionally, the housing 102 can be crimped, for example, to minimize the axial clearance between the thirteenth locator surface 114m and the fourteenth locator surface 114n, to axially constrain the idler bearing 172. The axially constrained idler bearing 172 can control the axial clearance between the second encoder magnet 368b and the second sensor 414b, for example, to maintain the second encoder magnet 368b within a predetermined range of the second sensor 414b.

[0130] The second seal 120b is disposed at the second end 106 of the housing 102. The second seal 120b is substantially the same as the first seal 120a. The second seal 120b covers the second end 106 of the housing 102. Specifically, the second seal 120b extends radially from the idler shaft 154 to the housing 102. The idler shaft 154 rotates sealingly relative to the housing 102 via the second seal 120b, and the second seal seals relative to the sealing portion of the idler shaft 154 and the inner surface 184 of the housing 102. The second seal 120b prevents fluid communication between the cavity 110 and the environment around the housing 102 through the second end 106.

[0131] The rotary actuator 100 may include grease or the like disposed in the cavity 110 adjacent to the second seal 120 b. The grease may be any suitable type of water-resistant grease. The grease may reduce the likelihood of water intrusion into the cavity 110.

[0132] The rotary actuator 100 may include an arm (not shown) disposed outside of the cavity 110. The arm extends from the idler shaft 154 to the output shaft 134. The arm is non-rotatably connected to the idler shaft 154 and the output shaft 134. That is, the idler shaft 154 is non-rotatably connected to the output shaft 134 via the arm. In other words, rotation of the output shaft 134 causes the arm to rotate, which in turn causes the idler shaft 154 to rotate in unison with the output shaft 134. The arm may be any suitable material. For example, the arm may be a non-corrosive metal, such as stainless steel.

[0133] Now go to Figure 8 , the rotary controller 400 may include a computer 416 that electronically communicates with the sensor 414 and the electric motor 302 over a communication network 418 via known wired mechanisms and / or wireless mechanisms. The computer 416 and the communication network 418 are part of the rotary controller that resides within the housing 102. Via the communication network 418, the computer 416 may send electronic messages to various components in the rotary actuator 100 and / or receive electronic messages from various components such as the sensor 414, the electric motor 302, etc. In addition, the computer 416 may be configured to electronically communicate with devices external to the rotary actuator 100 via the cable 124.

[0134] The computer 416 includes a processor and a memory such as is known. The memory includes one or more forms of computer-readable media and stores instructions that can be executed by the processor for performing various operations, including operations disclosed herein. The computer 416, i.e., components of the computer, can be supported by one or more of the circuit boards 412.

[0135] The computer 416 is programmed to receive data from the sensor 414 substantially continuously, periodically, and / or when instructed by a remote computing device. The data includes the angular position of the rotor shaft 308 and the angular position of the idler shaft 154. For example, the first sensor 414a can detect the angular position of the first encoder magnet 368a, and the second sensor 416b can detect the angular position of the second encoder magnet 368b, as discussed above. The angular position of the rotor shaft 308 corresponds to the angular position of the first encoder magnet 368a, and the angular position of the idler shaft 154 corresponds to the angular position of the second encoder magnet 368b. The sensor 414 can then provide the detected angular position of the encoder magnet 368 to the computer 416, for example, via the communication network 418. Then, the computer 416 can provide the angular position of the rotor shaft 308 and / or the angular position of the idler shaft 154 to the remote computing device, for example, via the cable 124. Additionally, computer 416 can actuate electric motor 302 to update the angular position of rotor shaft 308 so that the angular position of idler shaft 154 corresponds to a desired angular position specified, for example, in instructions received via a remote computing device. This dual sensor arrangement can compensate for inherent mechanical lash present within gearbox 200 or any other drive component.

[0136] Upon determining that the angular position of rotor shaft 308 corresponds to the desired angular position, computer 416 may compare the angular position of idler shaft 154 to the angular position of rotor shaft 308. If the angular position of idler shaft 154 matches the angular position of rotor shaft 308, i.e., is the same value or is within a specified error margin, computer 416 may determine that the angular position of idler shaft 154 corresponds to the desired angular position. In this case, computer 416 may stop actuation of electric motor 302.

[0137] If the angular position of the idler shaft 154 differs from the angular position of the rotor shaft 308, for example by more than a specified error margin, the computer 416 may determine the difference between the angular position of the idler shaft 154 and the angular position of the rotor shaft 308. The computer 416 may then actuate the electric motor 302 to rotate the rotor shaft 308 to compensate for the difference between the angular position of the idler shaft 154 and the angular position of the rotor shaft 308, for example by rotating the rotor shaft 308 in one direction to compensate for a positive difference or in another direction to compensate for a negative difference. Upon determining that the angular position of the idler shaft 154 corresponds to the desired angular position, the computer 416 may stop actuation of the electric motor 302.

[0138] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms covered by the claims. The words used in the specification are descriptive rather than restrictive words, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. As previously described, the features of various embodiments can be combined to form other embodiments of the present disclosure that may not be explicitly described or illustrated. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it is recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, applicability, weight, manufacturability, ease of assembly, etc. Therefore, in the sense that any embodiment is described as less desirable than other embodiments or prior art implementations in terms of one or more characteristics, these embodiments are not outside the scope of the present disclosure and may be desirable for specific applications.

Claims

1. A rotary actuator comprising: a hollow housing including a first end and a second end spaced apart from the first end along an axis, the hollow housing defining a cavity extending from the first end to the second end; an output shaft disposed coaxially with the axis and extending outwardly from the cavity through the first end; a drive system disposed in the cavity and drivably connected to the output shaft; a gearbox disposed in the cavity and axially arranged between the output shaft and the drive system, the gearbox being drivably connected to the drive system and the output shaft; as well as A rotation controller is disposed in the cavity between the drive system and the second end, the rotation controller being configured to actuate the drive system to adjust an angular position of the output shaft.

2. The rotary actuator according to claim 1, wherein: The hollow housing is a one-piece housing.

3. The rotary actuator according to claim 2, further comprising a first seal disposed at the first end and a second seal disposed at the second end, wherein: The first seal and the second seal are configured to prevent fluid communication between the cavity and an environment surrounding the hollow housing via the first end and the second end.

4. The rotary actuator according to claim 3, wherein: The rotary actuator is configured to operate while submerged in a fluid.

5. The rotary actuator according to claim 1, wherein: The drive system comprises: an electric motor having a rotor shaft; a bearing housing defining a bearing housing cavity extending axially therethrough, the rotor shaft extending partially through the bearing housing cavity; an encoder magnet connected to the rotor shaft and detectable by the rotation controller, the encoder magnet disposed within the bearing housing cavity; and A shield covers the bearing housing cavity and is disposed between the encoder magnet and the rotation controller.

6. The rotary actuator according to claim 5, wherein: The bearing housing and the shroud are configured to prevent fluid communication through the bearing housing cavity.

7. The rotary actuator according to claim 1, wherein: The gearbox is a strain wave gearbox.

8. The rotary actuator according to claim 1, wherein: The rotary controller is covered with a potting compound.

9. The rotary actuator according to claim 8, wherein: The potting compound fills the cavity around the rotation controller.

10. The rotary actuator of claim 1, further comprising an idler shaft coaxially disposed with the axis, the idler shaft extending outwardly from the cavity through the second end, and the rotary controller being disposed between the drive system and the idler shaft.

11. The rotary actuator according to claim 10, wherein: The rotation controller includes a first sensor configured to detect an angular position of a rotor shaft of the electric motor and a second sensor configured to detect an angular position of the idler shaft, the first sensor and the second sensor being axially spaced from each other.

12. The rotary actuator according to claim 11, wherein: The first sensor and the second sensor are disposed within the cavity.

13. The rotary actuator according to claim 12, wherein: The first sensor and the second sensor are arranged coaxially with the axis.

14. The rotary actuator according to claim 1, wherein: The drive system and the gearbox are arranged coaxially with the axis.

15. A rotary actuator configured to be immersed in a fluid, the rotary actuator comprising: A one-piece hollow shell extending along an axis, the one-piece hollow shell having: a first sealed end portion and a second sealed end portion; a longitudinal cavity extending from the first sealed end to the second sealed end; a plurality of axial segments defining a plurality of inner diameters of the longitudinal cavity; an output shaft disposed coaxially with the axis and extending outwardly from the longitudinal cavity through the first sealed end; a drive system disposed within the longitudinal cavity and drivably connected to the output shaft; a gearbox disposed within the longitudinal cavity and axially arranged between the output shaft and the drive system; as well as A rotation controller is disposed in the longitudinal cavity between the drive system and the second sealed end, the rotation controller being configured to actuate the drive system to adjust an angular position of the output shaft.

16. The rotary actuator according to claim 15, wherein: The rotation controller is arranged in a first axial segment defining a first inner diameter among the plurality of axial segments, and a second axial segment of the plurality of axial segments immediately adjacent to the first axial segment of the plurality of axial segments defines a second inner diameter; and a third axial segment of the plurality of axial segments immediately adjacent to the first axial segment of the plurality of axial segments defines a third inner diameter; and The second inner diameter and the third inner diameter are smaller than the first inner diameter.

17. The rotary actuator of claim 16, further comprising an idler shaft disposed coaxially with the axis, the idler shaft extending outwardly from the longitudinal cavity through the second sealed end, and the rotary controller disposed between the drive system and the idler shaft.

18. The rotary actuator of claim 17, further comprising: an opening in the one-piece hollow housing, the opening being disposed axially between the first sealed end and the second sealed end of the one-piece hollow housing; as well as A cable is configured to extend through the opening and connect with the rotary controller.

19. The rotary actuator of claim 17, wherein: The drive system includes an electric motor; The rotation controller comprises: a first rotational position sensor configured to detect an angular position of a rotor shaft of the electric motor; and A second rotational position sensor is configured to detect an angular position of the idler shaft.

20. The rotary actuator of claim 19, wherein: The gearbox is a strain wave gearbox.

Images