Rotary motion control device with zero backlash, including pins.

Abstract

A zero-backlash rotary motion control device includes a housing having a cylindrical outer surface and an operating cavity. The device further includes a rotor, an operating plate, and a flexible plate. The rotor includes a hub received within the operating cavity, a friction facing, and a disk extending between the friction facing and the hub. The friction facing is positioned between the operating plate and the outer flange of the housing. The device includes at least one pin that abuts around the operating plate and rotationally restricts the operating plate. The flexible plate is flexible enough to allow the operating plate and any flexible plate attached to it to move axially away from the housing. A spring biases the operating plate, sandwiching the friction facing between the flange and the operating plate. An electromagnet in the housing can be energized to pull the operating plate against the spring bias.

Description

[[BACKGROUND ART]]

[0001] An apparatus for controlling rotational motion that achieves zero backlash and a method for manufacturing the same are illustrated and described. Rotary brakes transmit torque from a rotatable shaft to a stationary housing, and are applicable to commonly used actuation methods including, but not limited to, electromagnetic, pneumatic, and hydraulic types. In conventional rotary brakes, axial movement of internal components is used to capture or engage the rotatable rotor, resulting in a mechanical connection between the stationary component and the axially translating component. Common methods for mechanically connecting axially movable components include splines, pins, studs, and bushings, all of which require mechanical clearance for free operation. Clearance results in loss of stiffness and torsional backlash, which can cause undesirable movement of a locked shaft in applications. Accordingly, there is a need for an apparatus that controls rotational motion to achieve zero backlash.

[0002] Patent Document 1 discloses a rotational motion control device comprising: an annular housing having a cylindrical outer surface extending between a first end and a second end and an operating cavity; a rotor rotatably received within the operating cavity, the rotor including a hub, an annular friction facing, and a disk extending between the friction facing and the hub that allows flexible movement of the friction facing relative to the hub; an annular actuation plate movably connected to the housing via a flexible plate, slidable on a pin, with the friction facing positioned between the actuation plate and the housing; and a spring that biases the actuation plate toward the friction facing to clamp the friction facing between the housing and the actuation plate, wherein the actuation plate is moved against the biasing force of the spring.

[0003] Even more interesting are Patent Documents 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. In addition, Patent Documents 12, 13, 14, and 15 are also of interest. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] British Patent No. 878273 [Patent Document 2] U.S. Patent No. 3071226 [Patent Document 3] U.S. Patent No. 8851258 [Patent Document 4] China Utility Model No. 201916038 Specification [Patent Document 5] China Utility Model No. 203463518 Specification [Patent Document 6] China Utility Model No. 206903736 Specification [Patent Document 7] China Utility Model No. 210686765 Specification [Patent Document 8] French Patent No. 1071474 [Patent Document 9] Korean Patent Publication No. 10-1664499 [Patent Document 10] International Publication No. 2010 / 001827 [Patent Document 11] U.S. Patent Application Publication No. 2011 / 0036678 [Patent Document 12] European Patent Application Publication No. 0222312 [Patent Document 13] French Patent Application Publication No. 1531246 [Patent Document 14] European Patent Application Publication No. 0209943 [Patent Document 15] U.S. Patent No. 3,893,191 [Overview of the Initiative]

[0005] This and other needs in the field of rotational motion control are addressed by providing a rotational motion control device with zero backlash. Specifically, the rotational motion control device comprises a housing and an actuation plate, with a flexible plate fixed to the housing and movably connecting the actuation plate to the housing. The flexible plate is flexible enough to allow the actuation plate and the flexible plate fixed thereto to move axially away from the housing, so as to create a friction surface between the housing and the actuation plate. A pin restricts the radial movement of the actuation plate but allows axial movement. This prevents excessive stress on the flexible plate during dynamic or emergency stops.

[0006] In addition, the housing of the rotary motion control device includes an output flange having a second flat surface among first and second spaced parallel flat surfaces that abut against the first end of the housing and abut against the friction surface.

[0007] Furthermore, the rotational motion control device further includes an electromagnet located on the same side as the spring of the actuating plate within the housing, the electromagnet attracting the actuating plate toward and against the biasing force of the spring, and an annular cavity within the housing receiving the electromagnet. A cylindrical cavity within the housing receives the spring, and the cylindrical cavity is located within the housing concentrically within and away from the annular cavity. A first fastener extends into the actuating plate through a flexible plate, and the first fastener extends into the annular cavity. A second fastener extends into the housing through a flexible plate, and the second fastener is located concentrically within the cylindrical cavity. A bore extends through the actuating plate, and the second fastener extends through the bore.

[0008] Exemplary embodiments will become clearer in light of the following detailed description, which is illustrated in relation to the drawings. Exemplary embodiments can be best described by reference to the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] For ease of illustration, an exploded perspective view of the rotary motion control device with the operating mechanism removed is shown. [Figure 2] Figure 1 shows a cross-sectional view of the rotational motion control device, including the operating mechanism, in the disengaged position. [Figure 3] Figure 1 shows a cross-sectional view of the rotational motion control device, including the operating mechanism, in the engaged position. [Modes for carrying out the invention]

[0010] All drawings are provided solely to facilitate the explanation of the basic teachings of the present invention. Further diagrammatic extensions relating to the number, location, relationships, and dimensions of parts for forming exemplary embodiments will be explained after the following description has been read and understood, or will be within the scope of the skills of those skilled in the art. Furthermore, precise dimensions and dimensional ratios for meeting specific forces, weights, strengths, and similar requirements will also be within the scope of the skills of those skilled in the art after the following description has been read and understood.

[0011] Where used in various drawings, the same numbers indicate the same or similar parts. Furthermore, where the terms “top,” “bottom,” “first,” “second,” “front,” “rear,” “reverse,” “front,” “rear,” “height,” “width,” “length,” “end,” “side,” “horizontal,” “vertical,” and similar terms are used herein, it should be understood that these terms refer only to the structures shown in the drawings and are used solely to facilitate the description of exemplary embodiments, as will be obvious to the viewer of the drawings.

[0012] The rotary motion control device is shown in the drawings and is denoted as 10 as a whole. The device 10 includes an annular housing 12. In one mode of operation, the housing 12 is held stationary relative to the ground so that the device 10 acts as a brake. The housing 12 has a cylindrical outer surface 14 extending between a first end 16 and a second end 18. The cylindrical bore 20 extends axially between the ends 16 and 18 and substantially concentrically with the surface 14. The cylindrical cavity, defined by the cylindrical wall 22, extends axially from the end 16 toward the second end 18, but away from the second end 18, and extends substantially concentrically with the outer surface 14 and inward from the outer surface 14, terminating at a radially extending wall 24. The annular cavity 26 extends axially from the radially extending wall 24 toward the end 18, but is separated from the end 18 and extends concentrically between the cylindrical bore 20 and the outer surface 14, and is also separated from the cylindrical bore 20 and the outer surface 14. The multiple cylindrical cavities 28 extend axially from the radially extending wall 24 and are located concentrically within the annular cavity 26, and are separated from the annular cavity 26, and are located between the annular cavity 26 and the cylindrical bore 20, and are also separated from the annular cavity 26 and the cylindrical bore 20. The multiple threaded cylindrical cavities 30 extend axially from the radially extending wall 24 and are located between the annular cavity 26 and the cylindrical bore 20, and are separated from them, and are located circumferentially in the middle of the multiple cylindrical cavities 28. Each of the threaded cylindrical cavities 30 includes a relief boss 32 formed in a radially extending wall 24 and intersecting the annular cavity 26. The elongated bore 37 extends axially between the ends 16 and 18, and between and away from the outer surface 14, the cylindrical wall 22, and the annular cavity 26.

[0013] The housing 12 includes an annular output flange 34 having a diametrical extent corresponding to the outer surface 14. The output flange 34 may extend beyond the outer surface 14, and may be circular, square, or other shapes. The output flange 34 has first and second spaced apart parallel flat surfaces. The second surface of the output flange 34 abuts the first end 16, is fixed to the housing 12 by a plurality of bolts 36 that extend axially through the elongated bores 37 and threadably engage with the threaded bores 38 formed in the output flange 34. The output flange 34 includes a diametrically sized cylindrical bore 40 positioned between and spaced apart from the central bore 20 and the annular cavity 26. An operating cavity having a minimum radial extent defined by the cylindrical wall 22 is defined between the output flange 34 and the radially extending wall 24. The annular cavity 26, the cylindrical cavity 28, and the threaded cylindrical cavity 30 extend axially within the housing 12 on the opposite side from the output flange 34.

[0014] The apparatus 10 also includes a rotor 46 received within the operating cavity. The rotor 46 includes a hub 48 fixed to a rotatable shaft. The rotor 46 may be slidably fixed onto the rotatable shaft by means such as a keyway. The rotor 46 includes an annular-shaped friction facing 50 that has an inner radial extent 50a larger than the cylindrical bore 40 and an outer radial extent 50b smaller than the cylindrical wall 22, and abuts against the second face of the output flange 34. A disk 52 extends integrally between the inner radial extent 50a and the hub 48. The rotor 46 is formed as a single piece of homogeneous material. The disk 52 has an axial thickness substantially thinner than that of the hub 48 and the friction facing 50, allowing flexible movement of the friction facing 50 relative to the hub 48. However, the rotor 46 may take other forms and types suitable for providing rotatable engagement and disengagement. By way of example, the rotor 46 may be of a design that minimizes or eliminates flexible movement. Likewise, different methods of engaging and disengaging the rotor 46 may be utilized, including but not limited to having a toothed interface surface. In this regard, the rotor 46 may be of any form or type that allows the rotor 46 to be freely rotatable relative to the housing 12 or rotatably fixed relative to the housing 12.

[0015] The apparatus 10 further includes an annular-shaped actuation plate 60. The friction facing 50 is located intermediate between the actuation plate 60 and the second face of the output flange 34. The actuation plate 60 has an outer radial extent that is slightly smaller than the cylindrical wall 22 to be movably received within the cylindrical wall 22. The actuation plate 60 has an inner radial extent that is substantially coextensive with the cylindrical bore 20 and larger than the hub 48. A plurality of bores 62 extend through the actuation plate 60 at circumferentially spaced positions corresponding to the threaded cylindrical cavities 30. A plurality of threaded bores 64 extend through the actuation plate 60 at circumferentially spaced positions corresponding to the annular cavities 26.

[0016] The device 10 also includes a flexible plate 70, which includes an annular portion 72 sized to fit within the annular cavity 26. The flexible plate 70 may consist of two or more parts. A tab 78 extends radially outward from the annular portion 72. A fastener 76 extends through the tab 78 toward the output flange 34 and is screw-received into a threaded bore 64 to secure the flexible plate 70 to the actuation plate 60. The tab 74 extends radially inward from the annular portion 72 and is received within a relief boss 32. A fastener 80 extends axially through the tab 74 away from the output flange 34 and is screw-received into a threaded cylindrical cavity 30 to secure the flexible plate 70 to the housing 12. Thus, the actuation plate 60 is movably connected to the housing 12 by the flexible plate 70.

[0017] Appropriate means are provided for operating the device 10 and moving it between an engaged position and a disengaged position. In an exemplary embodiment, the device 10 includes a plurality of springs 86 located in a cylindrical cavity 28 for clamping the friction facing 50 between the output flange 34 of the housing 12 and the device 60, thereby biasing the actuation plate 60 toward the friction facing 50 away from the radially extending wall 24. The device 10 further includes a mechanism 90 for moving the actuation plate 60 toward the radially extending wall 24 against the biasing force of the springs 86. In the illustrated exemplary embodiment, the mechanism 90 is an electromagnet positioned in an annular cavity 26 and appropriately fixed therein by adhesive or the like. The mechanism 90 is located in the housing 12 on the opposite side of the actuation plate 60 from the output flange 34 and pulls the actuation plate 60 toward and against the biasing force of the springs 86. In particular, the actuation plate 60 is formed from a magnetic material, so that when the mechanism 90 is energized, the actuation plate 60 is pulled toward the biasing force of the spring 86, moves against it, and comes into contact with the radially extending wall 24. Similarly, when the mechanism 90 is not energized, the actuation plate 60 is not pulled toward the radially extending wall 24, but moves toward the radially extending wall 24 due to the biasing force of the spring 86. It should be understood that the flexible plate 70 has sufficient flexibility to allow the flexible plate 70, which is fixed to the actuation plate 60 by the actuation plate 60 and tab 78, to move toward the axially extending wall 24, thereby allowing the friction facing 50 to be sandwiched between the housing 12 and the output flange 34 of the housing 12, under the biasing force of the spring 86, by the housing 12 and tab 74. It should be understood that the mechanism 90 for moving the operating plate 60 may take other forms and types, including but not limited to electromagnetic, pneumatic, hydraulic, and / or manual operation.

[0018] When assembling the device 10, a fastener 76 is extended into a tab 78 and screwed into a bore 64 to secure the flexible plate 70 to the actuating plate 60. A spring 86 is positioned within the cylindrical cavity 28. In the illustrated exemplary embodiment, the mechanism 90 is positioned within the annular cavity 26 and is properly secured within the annular cavity 26. A fastener 80 extends into a tab 74 and screws into a threaded cylindrical cavity 30 to secure the flexible plate 70 and the actuating plate 60 to the housing 12, and the spring 86 is sandwiched between the actuating plate 60 and the closed end of the cylindrical cavity 28. The rotor 46 is positioned within a cylindrical cavity defined by the cylindrical wall 22. The output flange 34 is positioned to abut the first end 16 and the housing 12, and the bolt 36 extends axially through the bore 37 of the housing 12, radially outward from the operating cavity, and is screwed into a threaded cylindrical bore 38 that extends axially from the second face to the first face of the output flange 34.

[0019] In the operation of the illustrated exemplary embodiment, when the mechanism 90 is energized, the actuator plate 60 is drawn against the bias of the spring 86 and comes into contact with the radially extending wall 24. Thus, the axial distance between the actuator plate 60 and the output flange 34 is greater than the axial thickness of the friction facing 50. Thus, the rotor 46 and the shaft rotatably fixed thereto rotate freely relative to the housing 12. When the mechanism 90 is not energized, the actuator plate 60 moves away from the radially extending wall 24 under the bias of the spring 86 to engage with the rotor 46, sandwiching the friction facing 50 between the output flange 34 and the actuator plate 60, thereby rotatably fixing the rotor 46 to the housing 12. Assuming the housing 12 is rotatably fixed to the ground, the device 10 acts as a brake to stop the rotation of the rotor 46 and the shaft received therein. As the actuation plate 60 moves away from the radially extending wall 24, the rotor 46 is bent so that the friction facing 50 moves axially and comes into contact with the output flange 34 and the actuation plate 60. The flexible plate 70, fastened to the housing 12 by fasteners 80 and to the actuation plate 60 by fasteners 76, is rotatably fixed to the housing 12, but allows axial movement and operation without adding backlash. Furthermore, the disengagement of the friction facing 50 from the output flange 34 and the actuator plate 60 occurs without any external force applied to the rotor 46, resulting in zero torsional force acting on the rotatable shaft received by the hub 48 of the rotor 46.

[0020] The device 10 may also include a plurality of pins 100 arranged within a pin shaft 101. The pin shaft 101 is located within a radially extending wall 24. The pins 100 are arranged radially around the circumference of the actuation plate 60 and are located within actuation plate slots 102. The actuation plate slots 102 are located around the circumference of the actuation plate 60. The actuation plate slots 102 are located distal to the flexible plate 70.

[0021] The actuation plate slot 102 may be a hole or other cavity for preventing radial movement of the pin 100. The actuation plate slot 102 is any cavity in which the pin 100 can be fixed.

[0022] In one embodiment, the pin 100 does not contact the rotor 46. The pin restricts the radial movement of the actuation plate 60 but allows axial movement. Restricting the actuation plate 60 prevents excessive stress on the flexible plate 70 during dynamic or emergency stops. The pin 100 helps to support the actuation plate 60 during movement. This support also reduces the stress on the flexible plate 70, thus providing a zero-backlash condition.

[0023] Accordingly, the invention disclosed herein can be embodied in other specific forms without departing from its spirit or general characteristics, and since some of these forms are shown, the embodiments described herein should be considered in all respects to be illustrative and not limiting. The scope of the invention should be indicated not by the foregoing description but by the appended claims, and all modifications that fall within the meaning and scope of the equivalents of the claims are intended to be encompassed therein.

Claims

1. A rotational motion control device, An annular housing having a cylindrical outer surface extending between a first end and a second end, and an operating cavity, A rotor rotatably received within the operating cavity, comprising: a hub; an annular friction facing; and a disk extending between the friction facing and the hub, enabling the flexible movement of the friction facing relative to the hub; An annular operating plate, wherein the friction facing is located between the operating plate and the housing, A spring that biases the operating plate toward the friction facing, At least one pin positioned within a radially extending wall, wherein the pin abuts against the periphery of the actuation plate within the actuation plate slot, and the pin rotationally restricts the actuation plate; A flexible plate fixed to the housing and the actuation plate, which movably connects the actuation plate to the housing, wherein the actuation plate and the flexible plate fixed to the actuation plate have sufficient flexibility to move axially away from the housing, allowing the friction facing to be sandwiched between the housing and the flexible plate fixed to the housing at an intermediate position between the housing and the actuation plate. Equipped with, A rotary motion control device characterized in that the housing includes an annular output flange having first and second spaced parallel flat surfaces, the first end of the housing abuts against the second surface of the output flange, the friction facing abuts against the second surface of the output flange, and the friction facing is located midway between the operating plate and the second surface of the output flange.

2. The rotational motion control device according to claim 1, further comprising the at least one pin disposed within a pin shaft disposed within a radially extending wall, wherein the pin abuts against the periphery of the operating plate and is disposed within an operating plate slot.

3. The rotational motion control device according to claim 1, wherein the pins include a plurality of pins that rotationally restrict the operating plate.

4. The rotational motion control device according to claim 1, wherein the pin does not come into contact with the rotor.

5. The rotational motion control device according to claim 1, further comprising a plurality of pins arranged in a pin shaft arranged in the radially extending wall, wherein the pins abut against the operating plate.

6. The rotational motion control device according to claim 1, wherein the pin rotationally restricts the operating plate.

7. The rotary motion control device according to claim 1, further comprising a plurality of bolts extending axially through the housing radially outward of the operating cavity and a threaded bore extending axially from the second face to the first face of the output flange, wherein the plurality of bolts are screwably received in the threaded bore.

8. The rotational motion control device according to claim 1, further comprising an electromagnet disposed in the housing on the side of the operating plate opposite to the output flange, which pulls the operating plate toward and against the biasing force of the spring.

9. The rotational motion control device according to claim 1, further comprising an annular cavity extending axially into the housing on the opposite side of the output flange and receiving the electromagnet.

10. The rotary motion control device according to claim 1, further comprising a cylindrical cavity extending axially into the housing on the opposite side of the output flange and receiving the spring, wherein the cylindrical cavity is arranged concentrically within the annular cavity and spaced apart from the annular cavity within the housing.

11. The rotational motion control device according to claim 1, further comprising: a first fastener extending into the operating plate through the flexible plate toward the output flange, the first fastener extending into the annular cavity; and a second fastener extending into the housing away from the output flange through the flexible plate, the second fastener concentrically located within the cylindrical cavity.

12. A rotary motion control device according to claim 1, further comprising: a boss extending into the housing on the opposite side of the output flange and intersecting a threaded cylindrical cavity extending axially into the housing on the opposite side of the output flange, wherein the flexible plate includes an annular portion that is received in the annular cavity; and a first tab extending radially inward of the annular portion, wherein the second fastener extends inward through the first tab to the boss.

13. The rotational motion control device according to claim 1, wherein the flexible plate further comprises a second tab extending radially outward from the annular portion, and the first fastener extends through the second tab.

14. The rotational motion control device according to claim 1, wherein the flexible plate comprises an annular portion that is received in the annular cavity and a second tab extending radially outward from the annular portion, and the first fastener extends through the second tab.

15. The rotational motion control device according to claim 1, further comprising a bore extending through the operating plate, wherein the second fastener extends away from the output flange through the bore.

16. The rotational motion control device according to claim 1, wherein the disk has an axial thickness that is considerably thinner than the hub and the friction facing.

17. The rotational motion control device according to claim 1, wherein the hub is adapted to be slidably and fixedly received on a rotatable shaft.

18. The rotational motion control device according to claim 1, wherein the housing is adapted to be held stationary with respect to the ground.

19. Positioning a spring within an annular housing having a cylindrical outer surface extending between a first end and a second end, and an operating cavity, Position at least one pin on a wall extending radially, Positioning the pin within the operating plate slot located on the annular operating plate, Positioning the electromagnet within the housing, Extending the first fastener into the operating plate through the flexible plate, After extending the first fastener and positioning the spring and the electromagnet, the second fastener is extended into the housing through the flexible plate, and the flexible plate, which has sufficient flexibility to allow the operating plate and the flexible plate fixed to the operating plate to move axially away from the housing and sandwich the friction facing between the housing and the flexible plate fixed to the housing between the housing and the operating plate, is fixed to the housing and the operating plate, and the operating plate is movably connected to the housing, After extending the second fastener, the rotor, which includes an annular friction facing and a disk extending radially inward from the friction facing, and which allows the flexible movement of the friction facing relative to the operating plate and the output flange, is positioned within the operating cavity in the housing. After positioning the rotor, the output flange is fixed to the first end of the housing, having an annular output flange with first and second spaced parallel flat surfaces, wherein the first end of the housing abuts against the second surface of the output flange, the friction facing abuts against the second surface of the output flange, and the friction facing is located midway between the operating plate and the second surface of the output flange. A method that includes this.

20. The method according to claim 19, wherein extending the second fastener includes extending the second fastener through the bore of the operating plate and through the flexible plate into the housing.

21. The method according to claim 19, wherein positioning the spring includes positioning the spring within a cylindrical cavity extending axially within the housing, the spring biasing the actuation plate toward the rotor, and extending the second fastener includes extending the second fastener through a first tab that extends outside the annular portion of the flexible plate, is located within a boss formed within the housing, and intersects with a threaded cylindrical cavity extending axially within the housing.

22. The method according to claim 19, wherein positioning the electromagnet includes positioning the electromagnet within an annular cavity extending axially within the housing, the electromagnet attracts the actuation plate toward the electromagnet, and extending the first fastener includes extending the first fastener through a second tab extending inside the annular portion of the flexible plate and into the actuation plate, the first fastener extending into the annular cavity after positioning the second fastener.

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