WO2019099378A1

WO2019099378A1 - Rotary actuator with annular motor and gearset

Info

Publication number: WO2019099378A1
Application number: PCT/US2018/060745
Authority: WO
Inventors: Jinseok Jeon
Original assignee: Dura Operating, Llc
Priority date: 2017-11-14
Filing date: 2018-11-13
Publication date: 2019-05-23

Abstract

A rotary actuator includes a motor having a stator and a rotor driven for rotation relative to the stator, a gearset including an input gear coupled to the rotor for rotation with the rotor and an output gear coupled to the input gear, an output member coupled to the output gear so that the output member is rotated when the output gear rotates, a rotary position sensor member coupled to the output member for co-rotation with the output member. The rotary position sensor member may be directly connected to the output member for co-rotation with the output member. The rotary position sensor member may include a magnet carrier fixed to at least one of the output gear or the output member and coaxially arranged with the output member, and a magnet may be carried by the magnet carrier for rotation of the magnet as the output member rotates.

Description

ROTARY ACTUATOR WITH ANNULAR MOTOR AND GEARSET

Reference to Co-pending Applications

This application claims the benefit of U.S. Provisional Patent Application Serial

No. 62/585,777 filed November 14, 2017, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates to an actuator that includes an annular motor and a gearset through which a rotary output member is driven.

Background

Rotary actuators may be used to rotate a component among multiple positions. For example, a locking assembly, such as for a vehicle park lock, may include a lock body that is rotated from an unlocked position to a locked position. Some transmissions include shift-by-wire systems wherein a vehicle driver commanded shift of the vehicle transmission is electrically communicated to a rotary actuator that drives a transmission shift lever to a desired position to shift the transmission to a desired gear (e.g. park, reverse, neutral and one or more drive gears). The space in which such actuators need to be received is sometimes small, yet significant force may be needed for the actuator to drive the component among its positions. Accordingly, a powerful yet small actuator is needed in such situations. Summary

In at least some implementations, a rotary actuator includes a motor having a stator and a rotor driven for rotation relative to the stator, a gearset including an input gear coupled to the rotor for rotation with the rotor and an output gear coupled to the input gear, an output member coupled to the output gear so that the output member is rotated when the output gear rotates, a rotary position sensor member coupled to the output member for co-rotation with the output member. The rotary position sensor member may be directly connected to the output member for co-rotation with the output member. The rotary position sensor member may include a magnet carrier fixed to at least one of the output gear or the output member and coaxially arranged with the output member, and a magnet may be carried by the magnet carrier for rotation of the magnet as the output member rotates.

In at least some implementations, the magnet carrier includes a shaft that extends coaxially through the input gear from a first end coupled to the output member to a second end axially spaced from the output member. The shaft may extend coaxially through the rotor from a first end coupled to the output member to a second end axially spaced from the output member. The actuator may include a circuit board with a sensor element located adjacent to the magnet so that movement of the magnet is detected by the sensor element. An intermediate wall having an opening may be located between the output member and the circuit board, and the shaft may extend through the opening and from a first end coupled to the output member to a second end axially spaced from and on the opposite side of the intermediate wall as the output member. The actuator may include a housing having a first body coupled to a lower body with an interior defined between the bodies, and the motor, gearset, intermediate wall and circuit board may be received within the interior. The circuit board may be axially located on an opposite side of the stator as the output member.

In at least some implementations, the gearset includes a compound gearset. The compound gearset may include a first planetary gearset having a sun gear fixed to the rotor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation, and a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears, wherein the output member may be fixed to the second planet gear. The output member and second ring gear may be integrally formed in the same body.

In at least some implementations, a rotary actuator includes a housing having a first body and a second body and an interior between the first body and the second body, a stator received within the interior and connected directly to the housing, the stator having an axis and an axial height, an annular rotor located radially inwardly of the stator and defining an opening, an output member is driven by the rotor for rotation relative to the housing, and a bearing coupled to the rotor, received within the opening of the rotor, arranged concentric with the rotor and having an axial height that is less than the axial height of at least one of the rotor and stator. The bearing is fully axially overlapped by at least one of the rotor and stator. The stator may be annular and have a first face and a second face spaced axially from the first face, and the rotor and bearing may be located axially between the faces of the stator. The housing may include a shoulder engaged by the stator to axially locate the stator within the interior, and the shoulder may be defined by an outer edge of one of the first body or second body of the housing, which outer edge may define part of a junction between the first body and second body. An intermediate wall may be located at least partially within the interior, and in contact with the stator, and the bearing may be coupled to the intermediate wall. The stator may define an opening and the intermediate wall may include a projection having a shape that corresponds to the shape of the opening in the stator. The projection may be at least partially received within the opening to axially position the stator relative to the intermediate wall or the intermediate wall relative to the stator. With the rotor bearing also coupled to rotor and the intermediate wall, the rotor, rotor bearing and stator may be accurately located relative to each other.

In at least some implementations, the actuator includes a gearset including an input gear connected to the rotor for rotation with the rotor and an output gear coupled to the input gear and to the output member. The gearset may be a planetary gearset and the input gear is a sun gear of the planetary gearset. The gearset may be a compound planetary gearset having a first planetary gearset having a sun gear fixed to the rotor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation. The compound gearset may include a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears, and the output member is fixed to the second ring gear. The compound planetary gearset may provide a very high gear ratio of 100: 1 or greater, and may include coaxial input and output gears.

In at least some implementations, the actuator also includes a rotary position sensor member that includes a magnet and is coupled to the output member for co rotation with the output member. The rotary position sensor member may include a shaft coaxial with the output member and extending through the rotor opening.

In at least some implementations, a rotary actuator includes a motor, a compound planetary gearset and an output member driven by the gearset. The gearset has a first planetary gearset which has a sun gear driven for rotation by the motor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation. And the gearset includes a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears. The output member is fixed to the second ring gear for co rotation with the second ring gear, and the gear ratio from the sun gear to the second ring gear is sometimes 100 or 200: 1 and may be much higher, including 500: 1 or greater. The sun gear and output member may be coaxial.

In at least some implementations, the motor includes a stator and an annular rotor that defines an opening and the sun gear is fixed to the rotor and is coaxial with the rotor. A bearing may be fixed to the sun gear so that at least part of the bearing rotates with the sun gear. A bearing may be fixed to the output member so that at least part of that bearing rotates with the output member.

In at least some implementations, the output member is formed in the same piece of material as the second ring gear. The axial thickness of the second ring gear may be greater than the axial thickness of the first ring gear. A housing having an interior may be provided and the motor and gearset may be located within the interior, and the first ring gear may be integrally formed in the housing.

In at least some implementations, each first planet gear is formed in the same piece of material as a respective one of the second planet gears. Further, the first planet gears may have a different number of teeth than the second planet gears. And the planet carrier may include posts and each post may mount one first planet gear and one second planet gear.

In at least some implementations, a rotary actuator includes an electric motor having a stator and a rotor that is rotatable relative to the stator, a gearset including an input gear connected to the rotor for rotation with the rotor and an output gear coupled to the input gear so that the output gear rotates when the input gear rotates, an output member coupled to the output gear so that the output member is rotated when the output gear rotates, an electrical assembly including power control circuitry for the electric motor and a housing. The housing has a first body and a second body and an interior between the first body and the second body. The output member is received at least partially within or extends from the second body, the first body is axially spaced from the output member, and wherein the electrical assembly is received within the interior and axially within the first body. In at least some implementations, the output member is at one axial end of the housing and the electrical assembly is at the other axial end of the housing, within the interior. The rotor and output member may be coaxial. The output member may have a free end and the second body may axially overlap the free end. That is, the free end of the output may be received within the housing rather than extended out of the housing. Of course, the output member may instead extend out of the housing, if desired.

In at least some implementations, a magnetic sensor element is fixed to the output member for rotation with the output member, and the electrical assembly includes a sensor responsive to movement of the magnet. The electrical assembly may include a circuit board and a controller mounted to the circuit board, the sensor may be received on a side of the circuit board facing the output member and the controller may be mounted on the opposite side of the circuit board facing away from the output member.

An intermediate wall may engage at least one of the stator and rotor, and may be received within the interior and axially within the first housing. The sensor element and sensor may be located on one side of the intermediate wall and the motor and gearset may be located on the other side of the intermediate wall. The stator may include an opening and the intermediate wall may include a projection complementary in shape to and received at least partially within the opening.

The second body of the housing may include an opening aligned with the output member to permit access to the output member or the output member may extend outwardly from the housing. To axially locate the stator, the housing may include a locating feature engaged by the stator. The locating feature may include a radially inwardly extending shoulder, and the shoulder may be defined at a junction between the first body and second body. To inhibit entry of contaminants into the interior of the housing, a seal may be carried by the housing at the junction. Another seal may be carried by the second body and engaged with the output member to provide a fluid-tight seal between the second body and the output member. Further, to guide rotation of and/or axially locate the output member, a bearing may be carried by the second body and engaged with the output member.

Brief Description of the Drawings

The following detailed description of representative implementations and best mode will be set forth with regard to the accompanying drawings, in which:

FIG. 1 is an exploded view of an actuator;

FIG. 2 is a cross-sectional perspective view of the actuator;

FIG. 3 is a cross-sectional side view of the actuator;

FIG. 4 is a perspective view of a gearset of the actuator;

FIG. 5 is a perspective view of the gearset with a sun gear removed;

FIG. 6 is a perspective bottom view of the sun gear;

FIG. 7 is a perspective top view of the sun gear; FIG. 8 is a perspective view of the gearset with the sun gear and a portion of planet carrier removed to show planet gears and ring gears of the gearset;

FIG. 9 is a perspective bottom view of a ring gear with integral output shaft; FIG. 10 is a perspective view of a magnet assembly, circuit board and sun gear;

FIG. 11 is a side view of the components shown in FIG. 10;

FIG. 12 is a perspective view of the magnet assembly mounted to the ring gear;

FIG. 13 is a perspective bottom view of an upper housing;

FIG. 14 is a perspective top view of a lower housing; and

FIG. 15 is a perspective bottom view of the lower housing.

Detailed Description

Referring in more detail to the drawings, FIGS. 1-3 illustrate a rotary actuator 10 having a motor 12 that, through a gearset 14, drives an output member 16 for rotation. The output member or output 16 may be a body that may have a connection feature (such as a socket in which a projection is received, or a projection for receipt in a socket of another component). Via the connection feature or otherwise, the output 16 may be coupled, for example and without intending to limit this disclosure, to an input shaft of a shifting mechanism 18 (FIG. 2) of an automotive vehicle transmission 20. In that example, rotation of the output 16 rotates the input shaft to shift the transmission from one gear to the next (e.g. from neutral to drive).

The motor 12 may include an annular rotor 22 that is driven for rotation about an axis 24. The rotor 22 has a radially outer surface 26 that defines an outer diameter of the rotor 22 and an inner diameter defined by a radially inner surface 28 that defines a central opening 30. The rotor 22 may have generally planar and axially opposed first and second faces 32, 34 that extend radially between the inner and outer surfaces 26, 28 and between which an axial thickness or axial height of the rotor is defined. The first and second faces 32, 34, as well as the inner and outer surfaces 26, 28 may be circumferentially continuous. In this way, the rotor 22 may define a hollow, right circular cylinder, although other constructions and arrangements may be used.

The rotor 22 is driven for rotation relative to a stator 36. In at least some implementations, the stator 36 is received radially outwardly of the rotor 22. In the example shown, the stator 36 is also annular and has a radially outer surface 38 that defines an outer diameter of the stator 36 and an inner diameter defined by a radially inner surface 40 that defines a central opening 42. The stator 36 may have generally planar and axially opposed first and second faces 44, 46 that extend radially between the inner and outer surfaces 38, 40 and between which an axial thickness or axial height of the stator is defined. The first and second faces 44, 46, as well as the inner and outer surfaces 38, 40 may be circumferentially continuous. In this way, the stator 36 may define a hollow, right circular cylinder, although other constructions and arrangements may be used.

The rotor 22 may be coaxially aligned with the stator 36, at least partially and up to fully axially overlapped by the stator 36, and received inwardly of the stator inner surface 40 with an air gap between them to permit relative rotation of the rotor 22. In the example shown, the stator 36 has greater axial thickness than the rotor 22, and the rotor 22 is fully axially overlapped and circumferentially surrounded by the stator 36. That is, the rotor 22 may be axially positioned between the axial location of the first and second faces 44, 46 of the stator 36. In at least some implementations, the motor 12 is a brushless motor 12 and hence, does not include a commutator and associated brushes and is instead a multi phase, electrically commutated motor 12. By way of non-limiting examples, the motor 12 may be a permanent magnet synchronous motor, asynchronous/induction motor or a switched reluctance motor.

As noted above, the motor 12 drives the gearset 14 of the actuator 10. The gearset 14 may include a planetary gearset 14, and as shown in FIGS. 1-9, at least some implementations may include a compound planetary gearset 14. The gearset 14 increases the torque provided from the motor 12 to the output 16 and thus, a smaller, less expensive and lighter motor 12 may be used to drive the output 16 at a desired torque.

The gearset 14 includes a sun gear 48 (FIGS. 2, 6, 10 and 11) that is coupled to and which may be fixed to and rotates with the rotor 22. The sun gear 48 may have or be carried by a hollow shaft 50 that is fixed to the rotor 22 at or near a first end 52. In the example shown, the hollow shaft 50 includes, at or near the first end 52 and axially aligned with the rotor 22, an internal counterbore 54 in which is located a bearing 56 that journals the shaft 50, and hence the rotor 22, for rotation. The bearing 56 may include an inner race 58 that is fixed against rotation (e.g. coupled to a plate, intermediate wall 60 or a portion of the housing 61 of the actuator 10) and an outer race 62 that is fixed to the shaft 50. In the example shown, the bearing 56 is annular and the inner race 58 is received around and fixed to a boss or projection 64 of the intermediate wall 60, and an outer surface of the outer race 62 is fixed to the shaft 50 within the counterbore 54. Thus, the bearing 56 is positioned within the opening of and is coupled of fixed to the rotor 22 by way of the connection of the rotor 22 to the shaft 50 and the shaft 50 to the bearing outer race 62. And the bearing has an axial height (measured between opposed axial faces of the bearing) that is less than the axial height of at least one of the rotor and the stator, and the bearing is fully axially overlapped by at least one of the rotor and the stator (e.g. received in an area axially between opposed axial faces of either or both of the rotor and stator).

The shaft 50 extends axially away from or outboard of the rotor 22 to a second end 66 that may engage a bearing or bushing 68 to axially locate the shaft 50 and j oumal the second end 66 of the shaft 50 for rotation. A radially extending step 70 (FIGS. 6, 10 and 11), may be provided to engage an axial end of the bearing or busing 68, which has its opposite axial end engaged with a support surface 72 (FIG. 12 - shown here as a base of a ring gear, as will be described in more detail below) and thereby axially locate the shaft 50 and sun gear 48 relative to the motor 12 and other gears in the gearset 14. The sun gear 48 may be fixed to the shaft 50 between the ends of the shaft 50, and may include a plurality of teeth 74 extending radially outwardly from the shaft 50. The sun gear 48 and shaft 50 could be integral and formed in the same piece of material. The sun gear 48 is coaxially arranged and axially aligned with one or more planet gears 76 of a first stage 78 of the compound gearset 14, hereafter called first planet gears 76.

The first planet gears 76 may be mounted on posts 80 (FIG. 1) of a planet carrier 82, and in the implementation shown, there are three posts 80 and three first planet gears 76. Each first planet gear 76 may include outwardly extending teeth 84 adapted to engage and be meshed with both the sun gear teeth 74 and teeth 86 of a first ring gear 88. The posts 80 may be equally radially spaced from the axis 24 of rotation of the sun gear 48 (and motor 12), and the first planet gears 76 may all be of the same size and are equally spaced apart circumferentially. Each first planet gear 76 may rotate about an axis 90 (FIG. 8) defined by its respective post 80 and the first planet gears 76 may also rotate with the carrier about its axis 24, which may be coaxially aligned with the sun gear 48, shaft 50 and motor 12. The planet carrier 82 may include axially spaced apart supports 92 to which the posts 80 are coupled or engaged and axially between which the first planet gears 76 are received. A first support may include a central opening 94 (FIG. 5) through which the shaft 50 and sun gear 48 extend.

As noted above, the first planet gears 76 are meshed with the first ring gear 88.

The first ring gear 88 is annular and includes inwardly extending teeth 86 about a radially inner surface. The first ring gear 88 may be fixed to the housing 61 so that the ring gear does not rotate as the sun gear 48, first planet gears 76 and planet carrier 82 rotate when driven by the motor 12. Because the first ring gear 88 is fixed against rotation relative to the housing 61, the first ring gear 88 may, if desired, be formed integrally with the housing 61. In the example shown, a lower body 110 of the housing 61 could include radially inwardly extending teeth that would define the first ring gear 88 and be meshed with and engaged by the first planet gears 76.

The compound gearset 14 also includes a second stage 98 which is also a planetary gearset. The second stage 98 includes one or more second planet gears 100 and a second ring gear 102 meshed with the second planet gears 100. Each of the second planet gears 100 is carried on a respective one of the posts 80 of the planet carrier 82, axially offset from a first planet gear 76 (although the first and second planet gears may be integrally formed in the same piece of material or otherwise fixed together, if desired) and axially aligned and meshed with the second ring gear 102. As shown in FIG. 8, the second planet gears 100 include outwardly extending teeth 104 meshed with inwardly extending teeth 106 of the second ring gear 102 so that the second planet gears 100 rotate relative to the planet carrier 82 about the posts 80 and with the planet carrier 82 as the planet carrier 82 rotates relative to the second ring gear 102. The second ring gear 102 is driven for rotation about the axis 24 by the second planet gears 100 as the planet carrier 82 is rotated. In this compound gearset 14 arrangement, a second sun gear is not needed, and only one planet carrier 82 is needed - the planet carrier 82 is shared by both stages of gears. If two separate planetary gearsets 14 were provided, a second sun gear could be fixed against rotation with the second ring gear 102 free to rotate, and a separate planet carrier could be provided for each stage of gears.

The output 16 is carried by the second ring gear 102 and rotates with the second ring gear 102. The output 16 may be a stub shaft cantilevered from the second ring gear 102 and may be integral with/formed in the same piece of material as the second ring gear 102. Hence, in this arrangement, the sun gear 48 is the input and the second ring gear 102 is or includes the output 16 of the gearset 14. The torque flow path then flows from the motor 12 to an input gear (e.g. the sun gear 48) to the first planet gears 76 and to the planet carrier 82, and from the planet carrier 82 to the second planet gears 100 and to an output gear (e.g. the second ring gear 102) which is coupled to the output 16. The torque may be increased by any desired amount between the motor l2/shaft 50 and the output 16. In at least some implementations, the torque at the output 16 may be between 100 and 1,000 times greater than the torque at the rotor 22, and in some implementations the torque ratio is at least 1,000:1. The second ring gear 102 may be thicker (axially) and have stronger teeth than the first ring gear 88, for example, to handle the greater torque and forces on the second ring gear 102. In the compound gearset 14, the first ring gear 88 may have a different number and arrangement of teeth compared to the second ring gear 102 (e.g. different gear ratios). Correspondingly, the first planet gear teeth may be different from the second planet gear teeth so that the planet gears 76, 100 smoothly mesh with their respective ring gear 88, 102. In this way, the torque increase provided by the first stage 78 may be different than that provided by the second stage 98. Of course, the gear teeth could be the same, if desired. Further, while planetary gears are shown and described, the gearset 14 could include cycloidal gears, spur gears, bevel gears, combinations of such gears or other gearsets, as desired.

The motor 12, sun gear 48, ring gears 88, 102 and planet carrier 82 may all be coaxially aligned and can be conveniently carried within the housing 61 which may have a width or diameter that is about the same width as the widest component of the motor 12 and gearset 14. In the example shown, the stator 36 has the largest diameter and is closely received within the housing 61 such that the thickness of the housing 61 walls is the only increase in the width/diameter of the assembly compared to the width/diameter of the stator 36. Further, the rotor 22, bearing 56 and part of the shaft 50 may be axially overlapped by the stator 36 (e.g. located axially between the first and second faces 44, 46 of the stator 36) to reduce the axial extent of the assembly. The planet carrier 82 may also be at least partially axially overlapped by the stator 36 (i.e. received within the opening 42 of the stator 36). With this arrangement, the ring gears 88, 102 both have an outer diameter larger than the inner diameter of the stator 36 and both ring gears are thus axially spaced from the stator 36. It may be possible for one or both ring gears 88, 102 to have a smaller outer diameter, in which case, at least one of the ring gears may be partially or fully received within the stator opening 42 and axially overlapped by the stator 36 to reduce the axial extent of the assembly, if desired.

In at least some implementations, as shown in FIGS. 1-3 and 13-15, the motor

12 and gearset 14 are received within a common housing 61 having first and second bodies, herein called upper and lower bodies, respectively although the installed position of the actuator may vary and the terms upper and lower are not intended to limit the possible installed orientations of the actuator. Both the lower and upper bodies 110, 112 may be generally cup-shaped and when they are coupled together, such as by fasteners, adhesive or a weld, the bodies collectively define an interior 114 (FIG. 3) in which the motor 12 and gearset 14 are received. A seal, such as an O-ring 116 may be provided at a junction between the bodies 110, 112 if desired, to prevent contaminants that could foul the motor 12 and gears from entering the housing interior 114 between the bodies.

In at least some implementations, the stator 36 may be axially received and located between an inwardly extending locating feature, such as a shoulder 118 (FIGS.

2, 3, 14) of the lower body 110, and another portion of the housing 61, such as the intermediate wall 60. The shoulder 118 may be defined at an outer edge 120 of a sidewall 122 of the lower body 110, and the edge 120 of the lower body 110 may be wider than the corresponding edge 124 of the upper body 112, as shown in FIGS. 2 and

3. The junction may be defined by or at the abutted edges 120, 124 of the bodies 110, 112. The stator 36 may be a machined or otherwise more dimensionally accurate and consistent part than the housing bodies 110, 112 (which may, for example, be cast or molded). Thus, the stator 36 may be used to locate the housing bodies 110, 112 relative to the stator 36 and each other, if desired. In at least some implementations, the stator 36 is directly connected (i.e. fixed) to the housing 61 and the rotor 22 is separately carried by the housing 61. That is, the stator 36 and rotor 22 are not contained within a casing that is then placed into the housing 61, and the stator 36 may directly engage the housing 61. In at least some implementations, the rotor 22 is coupled to the housing 61 independently of the connection of the stator 36 to the housing 61. In the example shown, the rotor 22 is coupled to the shaft 50 which is coupled to the bearing 56 which is coupled to the intermediate wall 60, and the stator 36 is coupled to one or both of the upper body 112 and the intermediate wall 60 at a location spaced from the location at which the rotor 22 is coupled to the intermediate wall. The lower body 110 can include a base 126 coupled to the sidewall 122 with an opening 128 through the base that is aligned with the output 16. As shown in FIG. 3, to guide andjoumal the output 16 for rotation, a bearing 130 may be provided between the lower body 110 (e.g. within a projection 132 that surrounds or defines the opening 128) and the output 16. An inner race of the bearing may be fixed to the output 16 and an outer race may be fixed to or received against the lower body 110. The bearing 130 may be axially located by a shoulder 134 in the projection 132, and the bearing may axially locate the output 16 and second ring gear 102 to facilitate rotation of the second ring gear 102 relative to the housing 61. An annular seal 136 may be provided between the output 16 or bearing 130 and the lower body 110, to prevent intrusion of contaminants into the housing 61 between the output 16 and lower body 110. The output 16 may extend into or through the opening 128 to facilitate coupling the output to the transmission or other driven component, or an end (e.g. free end) of the output may be received within and axially overlapped by the projection 132 or other portion of the lower body 110.

The lower body 110 may include one or more holes 138 through which fasteners may be received to mount the lower body 110 to another component, such as a transmission case. The lower body 110 may be formed of any desired polymeric, composite or metal material that is sufficiently strong to maintain axial rotation of the output 16 and sufficiently durable and resistant to the operating conditions in which the housing 61 is used. With an automotive transmission, the lower body 110 may be subjected to temperatures of 150 degrees Celsius or more. If desired the lower body 110 may include ribs, fins or other heat dissipating features.

The upper body 112 may have a base 139 and a sidewall 140 with an inner surface 142 sized for close receipt of the stator 36 and/or intermediate wall 60 which may be axially located within the upper body 112. In at least some implementations, the stator 36 may be press-fit into the upper body 112. The intermediate wall 60 could be overmolded or otherwise coupled to the stator 36 to maintain the position of the intermediate wall in use. With the intermediate wall 60 fixed to the stator 36, the bearing 56 which is fixed to the intermediate wall (in this example), the shaft 50 which is fixed to the bearing 56, and the rotor 22 which is fixed to the shaft 50, can be accurately positioned relative to the stator 36. The upper body 112 may be formed of any desired polymeric, composite or metal material that is sufficiently durable and resistant to the operating conditions in which the housing 61 is used. With an automotive transmission, the upper body 112 may be subjected to temperatures of 150 degrees Celsius or more. If desired the upper body 112 may include ribs, fins or other heat dissipating features 144. The upper body 112 may include an opening 146 through which electrical connection(s) can be made to an electrical assembly that includes a circuit board 148 received within the housing 61, such as between the intermediate wall 60 and base 139 of the upper body 112. The opening 146 may receive a connector body and a seal may be provided to prevent contaminants from entering the housing 61.

In at least some implementations, the electrical assembly received within the housing 61 may include all components needed for operation of the actuator 10. Non limiting examples of components that may be included in the electrical assembly and which may be mounted on or coupled to the circuit board 148 include and are diagrammatically shown in FIG. 11, power control circuitry 150 for the motor 12, a controller 152 for the motor 12 which may be or include a microprocessor that also manages other functions of the actuator 10 and possibly other vehicle components, and a position sensor 154 able to provide feedback about the rotational position of the motor 12, gearset 14, output 16 or any or all of these. The upper body 112 may include pockets or recesses 157 (FIGS. 2, 3 and 13) into which circuit board components may extend, and some or all of the upper body 112 may engage some or all of the components to improve heat transfer from the components to the housing 61, if desired. In at least some implementations, the circuit board 148 may be overmolded by the housing 61 to provide more intimate contact between the components, circuit board 148 and housing 61, and reduce or eliminate air gaps, for improved heat transfer.

The position sensor 154 may be a non-contact type sensor, like a Hall-effect sensor or a sensor wherein a conductive contact member engages a variable resistor. The contact member, which moves, can be carried by the movable component the position of which is to be monitored, and the variable resistor, which may be stationary, can be carried (e.g. printed or wired) on the circuit board. In the example shown, the position sensor 154 is used to monitor the rotary position of the output 16. While not required, directly detecting or sensing the position of the output 16 as opposed to the position of the rotor 22, shaft 50 or another gear in the gearset 14 can be more accurate because of tolerances and necessary lash or gaps between gears/gear teeth in the gearset 14 which cause the position of the output 16 relative to these other components to be somewhat variable.

Accordingly, in at least some implementations, at least part of the position sensor 154 is directly coupled to the output 16 for co-rotation with the output 16. In at least some implementations, a rotary position sensor member, called first member 155, of the position sensor 154 is fixed to the second ring gear 102 for rotation with the second ring gear 102, and hence, the output 16 which is fixed to the second ring gear for co-rotation therewith. A sensor element, called a second member 158 (FIG. 11) which is responsive to movement of the first member 155, is carried by the circuit board

148. The second member 158 could be located elsewhere in the actuator 10 and communicated with the processor or controller 152 on the circuit board 148, if desired.

The second member 158 may be mounted on the side of the circuit board 148 facing the output 16 and the controller 152 may be mounted on the opposite side of the circuit board, facing away from the output. Further, the circuit board 148 could be located closer to the second ring gear 102 or output 16, but may then need to have an opening to accommodate one or more components of the gearset 14, such as the shaft 50, sun gear 48 and/or planet carrier 82. This would reduce the surface area of the circuit board which may be acceptable in some applications. This also positions the circuit board closer to the vehicle transmission or other component driven by the output 16 which may be at a higher temperature or otherwise not desirable in some applications (but acceptable in other applications and/or with the specific components being used). In at least some implementations, the circuit board 148 is located immediately adjacent to the base 139 of the upper body 112 (e.g. with direct contact or nothing but air between them) and is at the axially opposite end of the actuator 10 as is the output 16, and the circuit board may be on the opposite side of the stator as the output 16. Further, if desired, a single circuit board is provided in the actuator 10 and one of the two members 155, 158 of the sensor 154 is fixed to the circuit board 148.

In at least some implementations, the sensor 154 may be a Hall-effect or other type of magnetic sensor wherein the first member 155 is or includes a magnet 156 and the second member 158 includes a sensing device responsive to movement of the magnet 156. The first member 155 may also include a magnet carrier 160 that carries the magnet 156 and which is coupled, as shown in FIG. 12, at a first end 162 to at least one of the second ring gear 102 or the output 16 (which is fixed to or integrally formed with the second ring gear 102 or other output gear), and has a second end 164 adjacent to the circuit board 148. The magnet carrier 160 may include a magnet holder 166 at or near the second end 164, and an elongate shaft 168 extending from the magnet holder

166 to the first end 162 that is coupled to the second ring gear 102 and output 16. In the example shown, the second ring gear 102 includes a boss 170 with a cavity 172 (FIGS. 5 and 8) in which the first end 162 of the shaft 168 may be fixed, such as by a press-fit, adhesive, set screw, weld or otherwise. The shaft 168 extends through at least part of the motor 12 and gearset 14, and is shown as being coaxially arranged with the motor 12 and gearset 14, output 16 and extending through a central bore 173 of the shaft 50 and sun gear 48, to the second ring gear 102. Hence, the first end 162 of the shaft is coupled to the output 16 and the second end is axially spaced from the output 16.

To allow the shaft 168 to pass therethrough, the intermediate wall 60 may include an aligned opening 174, and the magnet holder 166 and second end 164 of the magnet carrier 160 are received on an opposite side of the intermediate wall 60 as the motor 12, gearset 14 and output 16. To journal or guide the magnet carrier 160 for rotation about the axis 24, a bushing, bearing 176 or both are provided between the shaft 168 and intermediate wall 60. Hence, the shaft 168 may be axially located at the first end 162 via its connection with the second ring gear 102 and at or near the second end 164 by the intermediate wall 60 (e.g. the opening 174) and/or the bushing/bearing 176. In this way, the magnet carrier 160 and magnet 156 can be restrained to rotation coaxially with the output 16 for accurate indication of the rotary position of the output 16. In the example shown, the magnet holder 166 includes a recess 178 formed in a head carried by the shaft 168 and having a larger outer diameter than the shaft 168. The magnet 156 may be circular or of any desired shape. The shaft 168 may be generally cylindrical and, if desired, may have a noncircular portion at or near the first end 162 which may be received in a complementary cavity in the second ring gear 102 to prevent relative rotation between the shaft 168 and second ring gear l02/output 16. With the circuit board 148 spaced from the motor 12 and gearset 14, no central opening is needed in the circuit board, and the second member 158 of the sensor 154 may be carried by the circuit board 148 in axial alignment with the magnet 156. Further, the second ring gear 102 and circuit board 148 may be consistently and accurately located relative to each other within the housing 61. This facilitates providing the magnet 156 in a consistent position relative to the sensor, with a desired axial gap between them for consistent position sensing among a production run of actuators. Further, the magnet 156 and second member 158 may be located on one side of the intermediate wall 60 (e.g. a side facing axially away from the output) and the motor 12 and gearset 14 may be located on the other side of the intermediate wall 60.

In at least some implementations, the intermediate wall 60 may include a cylindrical proj ection 180 (FIGS. 2 and 3) that defines a recess 182 in which the magnet holder 166 and magnet 156 are received for rotation relative to the intermediate wall 60. An outer diameter of the projection 180 may correspond in size to and be received at least partially in the opening 42 in the stator 36 such that the intermediate wall 60 has a portion received in the opening 42 to facilitate coaxial alignment of the intermediate wall 60 and the stator 36, and also the magnet carrier 160 and rotor 22 relative to the stator 36. The intermediate wall 60 may be formed from a non-magnetic material to provide a magnetic flux shield to inhibit a magnetic flux path through the wall and toward magnetic components beyond the wall (e.g. the stator 36 or rotor 22). The electrical assembly, including the circuit board and other components, may be at one axial end of the housing and the output member may be at or near the other axial end of the housing. The output may be close to a transmission or other object interfaced with the output and the electrical assembly may be axially spaced and separated from the transmission or other object.

While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.

Claims

Claims:

1. A rotary actuator, comprising:

a motor having a stator and a rotor driven for rotation relative to the stator; a gearset including an input gear coupled to the rotor for rotation with the rotor and an output gear coupled to the input gear;

an output member coupled to the output gear so that the output member is rotated when the output gear rotates; and

a rotary position sensor member coupled to the output member for co-rotation with the output member.

2. The actuator of claim 1 wherein the rotary position sensor member is directly connected to the output member for co-rotation with the output member.

3. The actuator of claim 2 wherein the rotary position sensor member includes a magnet carrier fixed to at least one of the output gear or the output member and coaxially arranged with the output member, and which also includes a magnet carried by the magnet carrier for rotation of the magnet as the output member rotates.

4. The actuator of claim 3 wherein the magnet carrier includes a shaft that extends coaxially through the input gear from a first end coupled to the output member to a second end axially spaced from the output member.

5. The actuator of claim 3 wherein the magnet carrier includes a shaft that extends coaxially through the rotor from a first end coupled to the output member to a second end axially spaced from the output member.

6 The actuator of claim 1 wherein the gearset includes a compound gearset.

7. The actuator of claim 6 wherein the compound gearset includes a first planetary gearset having a sun gear fixed to the rotor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation, and the compound gearset includes a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears, wherein the output member is fixed to the second ring gear.

8. The actuator of claim 7 wherein the output member and second ring gear are integrally formed in the same body.

9. The actuator of claim 3 which also includes a circuit board with a sensor element located adj acent to the magnet so that movement of the magnet is detected by the sensor element.

10. The actuator of claim 9 which also includes an intermediate wall located between the output member and the circuit board, and having an opening, and wherein the magnet carrier includes a shaft that extends through the opening and from a first end coupled to the output member to a second end axially spaced from and on the opposite side of the intermediate wall as the output member.

11. The actuator of claim 9 which also includes a housing having a first body coupled to a lower body with an interior defined between the bodies, and wherein the motor, gearset, intermediate wall and circuit board are received within the interior.

12. The actuator of claim 9 wherein the circuit board is axially located on an opposite side of the stator as the output member.

13. A rotary actuator, comprising:

a housing having a first body and a second body and an interior between the first body and the second body;

a stator received within the interior and connected directly to the housing, the stator having an axis and an axial height;

an annular rotor located radially inwardly of the stator and defining an opening; a bearing coupled to the rotor, received within the opening of the rotor, arranged concentric with the rotor and having an axial height that is less than the axial height of at least one of the rotor and stator and wherein the bearing is fully axially overlapped by at least one of the rotor and stator; and

an output member driven by the rotor for rotation relative to the housing.

14. The actuator of claim 13 wherein the stator is annular and has a first face and a second face spaced axially from the first face, and the rotor and bearing are located axially between the faces of the stator.

15. The actuator of claim 13 which also includes an intermediate wall located at least partially within the interior, wherein the intermediate wall contacts the stator and the bearing is coupled to the intermediate wall.

16. The actuator of claim 15 wherein the stator defines an opening and the intermediate wall includes a projection having a shape that corresponds to the shape of the opening in the stator.

17. The actuator of claim 13 which also includes a gearset including an input gear connected to the rotor for rotation with the rotor and an output gear coupled to the input gear and to the output member.

18. The actuator of claim 17 wherein the gearset is a planetary gearset and the input gear is a sun gear of the planetary gearset.

19. The actuator of claim 18 wherein the gearset includes a compound planetary gearset having a first planetary gearset having a sun gear fixed to the rotor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation, and the compound gearset includes a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears, wherein the output member is fixed to the second ring gear.

20. The actuator of claim 13 which also includes a rotary position sensor member that includes a magnet and is coupled to the output member for co-rotation with the output member, wherein the rotary position sensor member includes a shaft coaxial with the output member and extending through the rotor opening.

21. The actuator of claim 13 wherein the housing includes a shoulder engaged by the stator to axially locate the stator within the interior.

22 The actuator of claim 21 wherein the shoulder is defined by an outer edge of one of the first body or second body of the housing.

23. A rotary actuator, comprising:

a motor;

a compound planetary gearset having a first planetary gearset which has a sun gear driven for rotation by the motor, multiple first planet gears carried by a planet carrier and driven by the sun gear, and a first ring gear held against rotation, and the compound gearset includes a second planetary gearset having second planet gears driven by the planet carrier and a second ring gear driven by the second planet gears; and

an output member fixed to the second ring gear for co-rotation with the second ring gear, wherein the gear ratio from the sun gear to the second ring gear is at least 100: 1.

24. The actuator of claim 23 wherein the sun gear and output member are coaxial.

25. The actuator of claim 23 which also includes a bearing fixed to the sun gear so that at least part of the bearing rotates with the sun gear.

26. The actuator of claim 23 which includes a bearing fixed to the output member so that at least part of the bearing rotates with the output member.

27. The actuator of claim 23 wherein the motor includes a stator and an annular rotor that defines an opening and wherein the sun gear is fixed to the rotor and is coaxial with the rotor.

28. The actuator of claim 23 wherein the output member is formed in the same piece of material as the second ring gear.

29. The actuator of claim 23 wherein the axial thickness of the second ring gear is greater than the axial thickness of the first ring gear.

30. The actuator of claim 23 which also includes a housing having an interior and wherein the motor and gearset are located within the interior, and wherein the first ring gear is integrally formed in the housing.

31. The actuator of claim 23 wherein each first planet gear is formed in the same piece of material as a respective one of the second planet gears.

32. The actuator of claim 31 wherein the first planet gears have a different number of teeth than the second planet gears.

33. The actuator of claim 23 wherein the planet carrier includes posts and wherein each post mounts one first planet gear and one second planet gear.

34. A rotary actuator, comprising:

an electric motor having a stator and a rotor that is rotatable relative to the stator; a gearset including an input gear connected to the rotor for rotation with the rotor and an output gear coupled to the input gear so that the output gear rotates when the input gear rotates;

an output member coupled to the output gear so that the output member is rotated when the output gear rotates;

an electrical assembly including power control circuitry for the electric motor; and

a housing having a first body and a second body and an interior between the first body and the second body, wherein the output member is received at least partially within or extends from the second body, wherein the first body is axially spaced from the output member, and wherein the electrical assembly is received within the interior and axially within the first body.

35. The actuator of claim 34 wherein the output member is at one axial end of the housing and the electrical assembly is at the other axial end of the housing, within the interior.

36. The actuator of claim 34 which also includes a magnetic sensor element including a magnet fixed to the output member for rotation with the output member, and wherein the electrical assembly includes a sensor responsive to movement of the magnet.

37. The actuator of claim 36 wherein the electrical assembly includes a circuit board and a controller mounted to the circuit board, the sensor is received on a side of the circuit board facing the output member and the controller is mounted on the opposite side of the circuit board facing away from the output member.

38. The actuator of claim 34 which also includes an intermediate wall that engages at least one of the stator and rotor, and wherein the intermediate wall is received within the interior and axially within the first housing.

39. The actuator of claim 36 which also includes an intermediate wall that engages at least one of the stator and rotor, wherein the intermediate wall is received within the interior and axially within the first housing, and wherein the sensor element and sensor are located on one side of the intermediate wall and the motor and gearset are located on the other side of the intermediate wall.

40. The actuator of claim 34 wherein the second body includes an opening aligned with the output member.

41. The actuator of claim 38 wherein the stator includes an opening and the intermediate wall includes a projection complementary in shape to and received at least partially within the opening.

42. The actuator of claim 34 wherein the housing includes a locating feature engaged by the stator to axially locate the stator within the interior.

43. The actuator of claim 42 wherein the locating feature includes a radially inwardly extending shoulder.

44. The actuator of claim 43 wherein the shoulder is defined at a junction between the first body and second body.

45. The actuator of claim 44 which also includes a seal carried by the housing at the junction.

46. The actuator of claim 34 which also includes a bearing carried by the second body and engaged with the output member.

47. The actuator of claim 34 wherein rotor and output member are coaxial.

48. The actuator of claim 40 which also includes a seal carried by the second body and engaged with the output member to provide a fluid-tight seal between the second body and the output member.

49. The actuator of claim 34 wherein the output member has a free end and the second body axially overlaps the free end.