WO2019218047A1

WO2019218047A1 - Cycloidal speed reducer and method for retrofitting the same

Info

Publication number: WO2019218047A1
Application number: PCT/CA2018/050589
Authority: WO
Inventors: Michaël ROUSSEAU
Original assignee: 9188-7588 Quebec Inc.
Priority date: 2018-05-18
Filing date: 2018-05-18
Publication date: 2019-11-21

Abstract

A cycloidal speed reducer comprising: rotatable input and output shafts; an eccentric cam member mounted on the input shaft; at least one cycloidal disc rotatably mounted on the eccentric cam member, each cycloidal disc further having at least one circular pin opening and a plurality of teeth extending radially outwardly; a plurality of teeth members disposed annularly around the at least one cycloidal disc for meshingly engaging the plurality of teeth of a corresponding cycloidal disc; and an output flange extending radially outwardly from the output shaft and including at least one output pin extending into a corresponding pin opening of the cycloidal disc. In one embodiment, the output flange is removably fastened to the shaft. In one embodiment, the input shaft includes a tapered shaft portion and the eccentric cam member includes a tapered bore for receiving the tapered shaft portion.

Description

CYCLOIDAL SPEED REDUCER AND METHOD FOR RETROFITTING THE

SAME

TECHNICAL FIELD

The technical field generally relates to speed reducers, and more specifically to cycloidal speed reducers and to methods for retrofitting cycloidal speed reducers.

BACKGROUND

Cycloidal speed reducers are becoming increasingly popular as a means to transmit rotation from a rotating actuator such as a motor to a rotating shaft of a device while reducing the rotation speed provided by the actuator.

Typically, a cycloidal speed reducer includes an input shaft which is inserted through an eccentric core which includes one or more eccentric cam members mounted on the input shaft. A toothed cycloidal disc is further mounted around each eccentric cam via a roller bearing, such that the input shaft is offcentered relative to the cycloidal discs. In this configuration, rotation of the input shaft causes the cycloidal disc to move in a circular path around the input shaft. The roller bearing is further disposed within an annular gear member with teeth which mesh with the cycloidal disc to rotate the cycloidal disc as it moves in its circular path. The output shaft includes a disc or flange and a plurality of pins or rollers which extend away from the disc and into holes of the cycloidal disc. This arrangement allows the cycloidal disc to rotate the output shaft at a rotation speed which is lower than the rotation speed of the input shaft as the cycloidal disc rotates and simultaneously moves in a circular path.

It has been observed that due to the specific movement of the components in this type of speed reducer, there may be a tendency for cycloidal speed reducers to become worn and/or be damaged in certain specific areas.

For example, the pins of the output shaft could become worn or be damaged or broken. In other cases, the opposite end of the output shaft, which may include a key to be connected to a rotating shaft of a device, may be subjected to wear which may reduce its diameter, which may cause the key and/or corresponding keyway to become warped or which may even cause the entire output shaft to crack. Unfortunately, these types of failures usually require the entire output shaft, including the disc or flange of the output shaft, to be replaced, which can be time consuming and/or expensive. Furthermore, the input shaft is usually connected to the eccentric core by inserting the shaft through a cylindrical bore extending through the eccentric core and prevented from rotating relative to the eccentric core by a key which extends into a keyseat defined in the shaft and a keyway defined in the core. Unfortunately, in some circumstances, the key may become damaged or break which prevents the reducer from functioning.

There is therefore a need for a cycloidal speed reducer which would be more durable and/or would be configured so as to facilitate the replacement of parts which are worn or damaged.

SUMMARY

According to one aspect, there is provided a cycloidal speed reducer comprising: a rotatable input shaft; a rotatable output shaft; and a transmission assembly operatively connecting the input shaft to the output shaft for transmitting rotation of the input shaft rotating at an input rotation speed to the output shaft, the transmission assembly including: an eccentric cam member mounted on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being sized and shaped to receive the input shaft therein, the shaft bore further being offcentered relative to the at least one cylindrical portion; at least one cycloidal disc, each cycloidal disc including a circular disc body having a central opening for rotatably receiving a corresponding cylindrical portion of the eccentric cam member such that rotation of the input shaft moves the cycloidal disc along a circular path, each cycloidal disc further having at least one circular pin opening spaced radially outwardly from the central opening and a plurality of teeth extending radially outwardly from the disc body; a plurality of teeth members disposed annularly around the at least one cycloidal disc, the teeth members being sized and shaped for meshingly engaging the plurality of teeth of a corresponding cycloidal disc to rotate the cycloidal disc as it moves along the circular path; and an output flange distinct from the output shaft and removably attached to the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed.

In one embodiment, the input shaft defines an input shaft axis and the output shaft defines an output shaft axis, the input and output shafts being disposed such that the input shaft axis and the output shaft axis extend parallel to each other.

In one embodiment, the input shaft and the output shaft are coaxial with each other. In one embodiment, the speed reducer further includes a flange connection assembly for removably connecting the driven flange to the output shaft.

In one embodiment, the flange connection assembly includes a mounting flange extending radially outwardly from the output shaft and a plurality of mounting fasteners configured for extending through the mounting flange and the output flange to removably fasten the output flange to the mounting flange.

In one embodiment, the output flange includes a circular flange body having a first face and a second face located opposite the first face, the at least one output pin extending generally orthogonally from the first face and away from the first face.

In one embodiment, the at least one output pin includes a plurality of output pins disposed annularly on the first face of the flange body.

In one embodiment, the output flange further includes a circular mounting recess defined in the flange body on the second face thereof, the circular mounting recess being sized and shaped to receive the mounting flange.

In one embodiment, the flange includes a plurality of mountings holes disposed annularly in the circular mounting recess, the mounting holes being sized and shaped to receive the mounting fasteners.

In one embodiment, each mounting hole is internally threaded.

In one embodiment, the plurality of mounting holes includes twelve mounting holes evenly distributed in a circular pattern around the central opening.

In one embodiment, the flange body is annular and has an outer circular edge and an inner circular edge defining a central flange opening, the circular mounting recess extending from the inner circular edge radially towards the outer edge.

In one embodiment, the output shaft includes a tubular rim projection extending away from the mounting flange, the tubular rim projection being sized and shaped to be snuggly received in the central opening of the output flange when the mounting flange is received in the circular mounting recess.

In one embodiment, the eccentric cam member includes a first cylindrical portion and a second cylindrical portion, the first and second cylindrical portions being offset relative to each other.

In one embodiment, the at least one cycloidal disc includes a first cycloidal disc and a second cycloidal disc parallel to and spaced apart from the first cycloidal disc, the first cylindrical portion of the eccentric cam member being rotatably received in the first cycloidal disc and the second cylindrical portion being rotatably received in the second cycloidal disc.

In one embodiment, the input shaft includes a tapered shaft portion and the shaft bore further being tapered to snuggly receive the tapered shaft portion.

According to another aspect, there is also provided an output assembly for a cycloidal speed reducer, the speed reducer including a rotatable input shaft, an eccentric cam member mounted on the input shaft and at least one cycloidal disc rotatably mounted to one of at least one cylindrical portions of the eccentric cam member, the cycloidal disc being offcentered relative to the input shaft such that rotation of the input shaft moves the cycloidal disc along a circular path, the speed reducer further including a plurality of teeth members disposed annularly around the cycloidal disc and the cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the cycloidal disc further including at least one circular pin opening, the output assembly comprising: a rotatable output shaft; and an output flange distinct from the output shaft and removably attached to the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the cycloidal disc such that movement of the cycloidal disc along the eccentric cycloidal path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed.

In one embodiment, the output assembly further includes a flange connection assembly for removably connecting the driven flange to the output shaft.

In one embodiment, the output flange further includes a circular mounting recess defined in the flange body on the second face thereof, the circular mounting recess being sized and shaped to receive the mounting flange. In one embodiment, the flange includes a plurality of mountings holes disposed annularly in the circular mounting recess, the mounting holes being sized and shaped to receive the mounting fasteners.

In one embodiment, each mounting hole is internally threaded.

According to yet another aspect, there is also provided a cycloidal speed reducer comprising: a rotatable input shaft having a tapered shaft portion; a rotatable output shaft; and a transmission assembly operatively connecting the input shaft to the output shaft for transmitting rotation of the input shaft rotating at an input rotation speed to the output shaft, the transmission assembly including: an eccentric cam member mounted on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft; at least one cycloidal disc, each cycloidal disc including a circular disc body having a central opening for rotatably receiving a corresponding cylindrical portion of the eccentric cam member such that rotation of the input shaft moves the cycloidal disc along a circular path, each cycloidal disc further having at least one circular pin opening spaced radially outwardly from the central opening and a plurality of teeth extending radially outwardly from the disc body; a plurality of teeth members disposed annularly around the at least one cycloidal disc, the teeth members being sized and shaped for meshingly engaging the plurality of teeth of a corresponding cycloidal disc to rotate the cycloidal disc as it moves along the circular path; and an output flange extending radially outwardly from the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed. In one embodiment, the tapered shaft portion includes a first end having a first diameter and a second end having a second diameter smaller than the first diameter, the first end being disposed away from the output shaft and the second end being disposed towards the output shaft.

In one embodiment, the input shaft includes an elongated key defined on the tapered shaft portion and extending parallel to the input shaft, and the eccentric cam member includes a corresponding keyway defined in the shaft bore for receiving the key to prevent rotation of the input shaft relative to the eccentric cam member.

In one embodiment, both the tapered input shaft portion and the shaft bore are tapered at a taper angle of 1 .4916 degrees.

In one embodiment, the output flange is distinct from the output shaft and removably attached thereto.

According to yet another aspect, there is also provided a method for retrofitting an existing cycloidal speed reducer, the existing cycloidal speed reducer including a rotatable non-tapered input shaft, a rotatable monolithic output assembly and a non-tapered eccentric cam member mounted on the non-tapered input shaft, the non-tapered eccentric cam member having a non-tapered shaft bore sized and shaped to receive the non-tapered input shaft therein, the existing cycloidal speed reducer further including at least one cycloidal disc mounted to at least one cylindrical portion of the eccentric cam member, the at least one cycloidal disc being offcentered relative to the non-tapered input shaft such that rotation of the non-tapered input shaft moves the at least one cycloidal disc along a circular path, the existing cycloidal speed reducer further including a plurality of teeth members disposed annularly around the at least one cycloidal disc and the at least one cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the at least one cycloidal disc further including at least one circular pin opening, the kit comprising: removing the monolithic output assembly; providing a rotatable output shaft; providing an output flange distinct from the output shaft and removably attachable to the output shaft, the output flange including at least one output pin configured for extending into a corresponding pin opening of the at least one cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed; removably attaching the output flange to the output shaft to thereby form an outlet assembly; installing the output assembly in the speed reducer. In one embodiment, the method further comprises removing the non-tapered input shaft and the non-tapered eccentric cam member from the existing cycloidal speed reducer; providing a rotatable input shaft having a tapered shaft portion; providing an eccentric cam member mountable on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft; mounting the eccentric cam member on the tapered shaft portion of the input shaft; installing the input shaft with the eccentric cam mounted thereon in the speed reducer.

According to yet another aspect, there is also provided a kit for retrofitting an existing cycloidal speed reducer, the existing cycloidal speed reducer including a rotatable non-tapered input shaft, a rotatable monolithic output assembly and a non-tapered eccentric cam member mounted on the non-tapered input shaft, the non-tapered eccentric cam member having a non-tapered shaft bore sized and shaped to receive the non-tapered input shaft therein, the existing cycloidal speed reducer further including at least one cycloidal disc mounted to at least one cylindrical portion of the eccentric cam member, the at least one cycloidal disc being offcentered relative to the non-tapered input shaft such that rotation of the non-tapered input shaft moves the at least one cycloidal disc along a circular path, the existing cycloidal speed reducer further including a plurality of teeth members disposed annularly around the at least one cycloidal disc and the at least one cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the at least one cycloidal disc further including at least one circular pin opening, the kit comprising: a rotatable output shaft; an output flange distinct from the output shaft and removably attachable to the output shaft, the output flange including at least one output pin configured for extending into a corresponding pin opening of the at least one cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed; a rotatable input shaft having a tapered shaft portion; and an eccentric cam member mountable on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-section view of a cycloidal speed reducer, in accordance with one embodiment;

FIG. 2 is a front elevation view of an output flange for the cycloidal speed reducer illustrated in FIG. 1 ;

FIG. 3 is a longitudinal cross-section view of the output flange illustrated in FIG. 2;

FIG. 4 is a front elevation view of an output shaft for the cycloidal speed reducer illustrated in FIG. 1 ;

FIG. 5 is a longitudinal cross-section view of the output shaft illustrated in FIG. 4;

FIG. 6 is a side elevation view of the input shaft for the cycloidal speed reducer illustrated in FIG. 1 ;

FIG. 7is a front elevation view of an eccentric cam member for the cycloidal speed reducer illustrated in FIG. 1 ;

FIG. 8 is a longitudinal cross-section view of the eccentric cam member illustrated in FIG. 7; and

FIG. 9 is a block diagram showing a method for retrofitting an existing cycloidal speed reducer, in accordance with one embodiment.

DETAILED DESCRIPTION

Referring first to FIG. 1 , there is shown a speed reducer 100, in accordance with one embodiment. The speed reducer 100 includes a housing, not shown, defining an inner chamber, rotatable input and output shafts 102, 104 extending into the chamber and a transmission assembly 106 disposed in the chamber and operatively connecting the input shaft 102 to the output shaft 104. The input shaft 102 is configured to be operatively connected to a rotating actuator such as a motor, not shown, and the output shaft 104 is configured to be operatively connected to a driven rotating device or machine, also not shown. When the input shaft 102 is rotated at a first rotation speed, the transmission assembly 106 causes the output shaft 104 to be rotated at a second rotation speed which is lower than the first rotation speed. Furthermore, by reducing the rotation speed between the input shaft 102 and the output shaft 104, the torque provided by the output shaft 104 is also increased relative to the torque provided at the input shaft 102, as is well known in the art. In the illustrated embodiment, the speed reducer 100 is an inline speed reducer. Specifically, the input shaft 102 and the output shaft 104 are coaxial to each other and extend along a common longitudinal shaft axis Li .

Still in the illustrated embodiment, the input shaft 102 includes a first end 108 and a second end 1 10 located away from the first end 108. Similarly, the output shaft 104 includes a first end 1 12 and a second end 1 14 located away from the first end 1 12. In the illustrated embodiment, the first end 108 of the input shaft 102 and the first end 1 12 of the output shaft 104 are disposed generally towards each other. Specifically, the first end 108 of the input shaft 102 is received in the first end 1 12 of the output shaft 104, as will be explained further below. The second end 1 10 of the input shaft 102 may be connected to the rotating actuator and the second end 1 14 of the output shaft 104 may be operatively connected to the driven rotating device or machine. Alternatively, the input shaft 102 and the output shaft 104 could be disposed relative to each other according to any other configuration. It will also be understood that the input shaft 102 and the output shaft 104 could alternatively have another length, diameter, shape and/or general configuration than those illustrated herein.

Still referring to FIG. 1 , the speed reducer 100 is a cycloidal speed reducer. More specifically, the transmission assembly 106 includes an eccentric core or eccentric cam member 1 16 which is mounted on the input shaft 102 and first and second cycloidal discs 1 18, 120 which are mounted around the eccentric cam member 1 16. The eccentric cam member 1 16 is configured such that the cycloidal discs 1 18, 120 are offcentered relative to the input shaft 102, as will be explained further below. Instead of rotating about their center, the cycloidal discs 1 18, 120 therefore move along a circular path around the longitudinal shaft axis Li .

In the illustrated embodiment, each cycloidal disc 1 18, 120 includes a generally circular disc body 122 which is substantially flat and which has a central disc opening 124 allowing the input shaft 102 to extend through the cycloidal disc 1 18, 120. Each cycloidal disc 1 18, 120 is further connected to the eccentric cam member 1 16 via a generally-annular bearing 126, such as a roller bearing. More specifically, the bearing 126 is concentrically received in the central disc opening 124 and the input shaft 102 extends concentrically through the bearing 126. In this configuration, the bearing 126 allows the cycloidal disc 1 18, 120 to rotate relative to the eccentric cam member 1 16 and to the input shaft 102. Alternatively, instead of a roller bearing, the bearing 126 could include a ball bearing, a plain bearing or any other type of bearing which the skilled person would consider to be appropriate. Moreover, the bearing 126 could include a custom bearing manufactured specifically for this particular application or a standard common- sized bearing as is widely currently available. Each cycloidal disc 1 18, 120 further has a gear-like configuration and includes a plurality of teeth 128 which extends radially outwardly from the disc body 122.

The speed reducer 100 further includes an outer gear assembly 130 which has a plurality of teeth members 132 disposed around the first and second cycloidal discs 1 18, 120 for operatively meshing with the teeth 128 of the cycloidal discs 1 18, 120 as the cycloidal discs 1 18, 120 move around their respective circular path.

Specifically, the outer gear assembly 130 includes an annular frame, not shown, which is longitudinally aligned with the cycloidal discs 1 18, 120, and the plurality of spaced-apart teeth members 132 are disposed annularly along the annular frame around the cycloidal discs 1 18, 120. In the illustrated embodiment, each tooth member 132 includes a pin 134 disposed generally parallel to the longitudinal shaft axis Li and first and second rollers 136, 138 rotatably mounted to the pin 134. The pin 134 extends longitudinally across the planes of the first and second cycloidal discs 1 18, 120, and each one of the first and second rollers 136, 138 is longitudinally aligned respectively with the first and second cycloidal discs 1 18, 120. It will be appreciated that in this configuration, the teeth members 132 mesh with the teeth 128 of the cycloidal discs 1 18, 120 to rotate the cycloidal discs 1 18, 120 as the cycloidal discs 1 18, 120 move along their respective circular paths, while the rollers 136, 138 reduce friction of the disc’s teeth 128 against the teeth members 132.

Alternatively, instead of first and second rollers 136, 138, each tooth member 132 may instead include a single roller which extends longitudinally across the planes of the first and second cycloidal discs 1 18, 120. In yet another embodiment, the outer gear assembly 130 may not include any rollers and may simply include rotating or non-rotating pins.

Still referring to FIG. 1 , the speed reducer 100 further includes an output assembly 140 which includes the output shaft 104 and an output flange 142 located at the first end 1 12 of the output shaft 104. In the illustrated embodiment, the output flange 142 is generally circular and extends radially outwardly from the output shaft 104. The output flange 142 further includes a plurality of pins 144 which extend from the output flange 142, away from the output shaft 104 and towards the input shaft 102. Each pin 144 extends generally parallel to the longitudinal shaft axis Li and is adapted to engage the first and second cycloidal discs 1 18, 120. More specifically, each cycloidal disc 1 18, 120 includes a plurality of circular pin openings 146, each circular pin opening 146 being sized and shaped for receiving a corresponding pin 144 of the output flange 142. In this configuration, the output flange 142, and therefore the output shaft 104, are rotated as the cycloidal discs 1 18, 120 rotate. In the illustrated embodiment, the plurality of pins 144 includes a number of pins which corresponds to the number of circular pin openings 146 defined in the cycloidal discs 1 18, 120. For example, the output flange 142 may include ten (10) pins and each cycloidal disc 1 18, 120 may include ten (10) pin openings 146. Alternatively, the output flange 142 and the cycloidal discs 1 18, 120 may respectively include more or less than ten (10) pins 144 and pin openings 146.

Still in the illustrated embodiment, the output flange 142 further includes a plurality of rollers 145, each roller 145 being rotatably mounted to a corresponding pin 144 and being adapted to rotate about the pin 144 to reduce friction between the pin 144 and the corresponding cycloidal disc 1 18, 120 which the pin 144 engages. Alternatively, the output flange 142 may not include any roller 145 and the pins 144 may directly contact the cycloidal discs 1 18, 120.

It will be appreciated that in the speed reducer 100 described above, the output flange 142 and/or the pins 144 of the output flange 142 may tend to become worn and damaged and/or break due to the forces which are applied to them during operation of the speed reducer 100. Alternatively, the output shaft 104 may also become worn and damaged and/or break due to the forces which are applied to them during operation of the speed reducer 100. In one embodiment, the flange 142 is distinct from the output shaft 104 and is removably mounted to the output shaft 104, such that the output flange 142 and/or the output shaft 104 may be easily removed and replaced when desired or needed, without having to remove and replace the other one of the output flange 142 and the output shaft 104.

Moreover, providing the output flange 142 as a distinct component from the output shaft 104 further allows the output flange 142 to be made according to a configuration, shape and/or material which is different from the output shaft 104. Therefore, specific combinations of configurations, shapes and/or materials for the output flange 142 and the output shaft 104 can be selected according to a specific application in which the speed reducer 100 is to be used.

Referring to FIGS. 1 -5, the output flange 142 is removably connected to the output shaft 104 by a flange connection assembly 150. In the illustrated embodiment, the flange connection assembly 150 includes a mounting flange 152 secured to the first end 1 12 of the output shaft 104 and a plurality of mounting fasteners, not shown, which are configured to extend through the mounting flange 152 and at least partially through the output flange 142.

In the illustrated embodiment, the output flange 142 includes a generally flat, circular flange body 200 which has a first face 202 and a second face 204 located opposite the first face 202. When the output flange 142 is mounted to the output shaft 104, the output flange 142 is oriented such that the first face 202 is disposed towards the input shaft 102 and the second face 204 is disposed towards the output shaft 104, away from the input shaft 102.

Still in the illustrated embodiment, the flange body 200 is annular. More specifically, the flange body 200 has an outer circular edge 206 and an inner circular edge 208 which defines a central flange opening 210 of the flange body 200. In this configuration, the first and second faces 202, 204 are therefore annular as well.

In one embodiment, the flange body 200 includes a plurality of pin bores 300 which are configured to receive the pins 144. Specifically, the pin bores 300 are evenly spaced around the central flange opening 210 and extend generally orthogonally to the first and second faces 202, 204 of the flange body 200. Each pin bore 300 may extend through the flange body 200, between the first face 202 and the second face 204 of the flange body 200, or partially through the flange body 200 from the first face 202 towards the second face 204. Each pin bore 300 is further generally cylindrical and is sized and shaped to receive a corresponding pin 144.

The pins 144 further have a length which is greater than a thickness of the flange body 200, defined between the first and second faces 202, 204. In the embodiment illustrated in FIG. 3, the pins 144 are inserted in their corresponding pin bores 300 such that the pins 144 extend beyond the first face 202 to engage the cycloidal discs 1 18, 120, but not beyond the second face 204. Alternatively, the pins 144 could extend beyond the second face 204 as well.

Once the pins 144 are inserted into the corresponding pin bores 300, the pins 144 may be secured to the flange body 200 by welding, gluing, interference fitting which may or may not include thermal shrink-fitting or using any other securing techniques known to a skilled person. In another embodiment, instead of the pins 144 being manufactured separately from the flange body 200 and then secured to the flange body 200, the flange body 200 and the pins 144 could be manufactured as a single, unitary body.

In the illustrated embodiment, the flange body 200 further includes a circular first recess or mounting recess 212 which extends from the second face 204 towards the first face 202. The mounting recess 212 is generally centred on the output flange 142 and is sized and shaped to receive the mounting flange 152. Specifically, the mounting recess 212 includes a first annular bottom face 214 a cylindrical sidewall 216 which extends around the mounting recess 212 and which is generally perpendicular to the annular bottom face 214 and the second face 204.

In the illustrated embodiment, the flange body 200 further includes a second circular recess 218 which extends from the first face 202 towards the second face 204. Still in the illustrated embodiment, the second circular recess 218 has generally the same diameter as the mounting recess 212 and includes a second annular bottom face 220 which is spaced from the first face 202 of the flange body 200 by a distance corresponding to a second recess depth. Alternatively, the second circular recess 218 could have a diameter which is greater or less and the diameter of the mounting recess 212.

As best shown in FIG. 2, the output flange 142 further includes a plurality of fastener bores 222 defined in the circular mounting recess 212 for receiving the mounting fasteners. Specifically, the fastener bores 222 are disposed annularly around the central flange opening 210 and extend through the flange body 200 between the first annular bottom face 214 of the mounting recess 212 and the second annular bottom face 222 of the second circular recess 218.

In the illustrated embodiment, the fastener bores 222 are threaded and are therefore adapted to receive corresponding threaded fasteners such as screws, threaded bolts or the like. Alternatively, the fastener bores 222 may be unthreaded and each fastener bore 222 may be adapted to receive a corresponding fastener such as a bolt with a nut engaging the bolt and abutting the second annular bottom face 220 to maintain the mounting flange 152 in abutment against the first annular bottom face 214 of the mounting recess 212.

Turning to FIGS. 4 and 5, the output shaft 104 includes a first end portion 500 located at the first end 1 12 of the output shaft 104, a second end portion 502 located at the second end 1 14 of the output shaft 104 and first and second intermediate portions 504, 506 located between the first and second end portions 500, 502. More specifically, the first intermediate portion 504 is located adjacent the first end portion 500 and the second intermediate portion 506 is located adjacent the second end portion 502.

In the illustrated embodiment, the diameter of the shaft portions 500, 502, 504, 506 decreases from the first end portion 500 to the second end portion 502. Specifically, the first end portion 500 has a first diameter and the first intermediate portion 504 has a second diameter which is substantially smaller than the first diameter, while the second intermediate portion 506 has a third diameter which is only slightly smaller than the second diameter and the second end portion 502 has a fourth diameter which is only slightly smaller than the third diameter. Alternatively, the output shaft 104 could have a different configuration. For example, the output shaft 104 could have more or less than four portions, and each portion could have a different diameter. The mounting flange 152 is located around the first end portion 500 and has a first annular face 400 facing away from the second end 1 14 of the output shaft 104 and a second annular face 402 facing towards the second end 1 14 of the output shaft 104. The mounting flange 152 further includes a plurality of mounting holes 404 which are disposed annularly on the mounting flange 152. The mounting holes 404 extend through the mounting flange 152 from the first annular face 400 to the second annular face 402 and are evenly distributed on the mounting flange 152 in an annular pattern which corresponds to the annular pattern of the fastener bores 222 on the output flange 142 such that each mounting hole 404 may be aligned with a corresponding fastener bore 222 of the output flange 142.

In the illustrated embodiment, the output flange 142 includes twelve (12) fastener bores 222 and the mounting flange 152 includes twelve (12) corresponding mounting holes 404. Alternatively, the output flange and the mounting flange 142 could include a different number of fastener bores 222 and mounting holes 404.

Still referring to FIGS. 4 and 5, the output shaft 104 further includes a tubular rim projection 508 which is located at the first end 1 12 of the output shaft 104 and which extends away from the mounting flange 152. The rim projection 508 is sized and shaped to be snuggly received in the central flange opening 210 of the output flange 142 when the mounting flange 152 is received in the mounting recess 212 of the output flange 142.

The rim projection 508 further defines a circular inner recess 510 which has a generally circular bottom wall 512 and a central cavity 514 extending from the bottom wall 512 towards the second end 1 14 of the output shaft 104. As shown in FIG. 1 , the central cavity 514 is configured to receive the first end 108 of the input shaft 102 and the inner recess 510 is adapted to receive a bearing 154 such as a roller bearing or any other suitable type of bearing mounted around the input shaft 102.

In the embodiment illustrated in FIGS. 4 and 5, the central cavity 514 is generally funnel-shaped and extends through the first end portion 500 and partially through the first intermediate portion 504 of the output shaft 104. This configuration corresponds to the configuration of the first end 108 of the input shaft 102. Alternatively, the first end 108 of the input shaft 102 could have a different configuration and the central cavity 514 could have a corresponding configuration to receive the first end 108 of the input shaft 102.

In the illustrated embodiment, the first end portion 500 of the output shaft 104 further has a generally conical lower surface 516 which is located between the mounting flange 152 and the first intermediate portion 504 of the output shaft 104. Specifically, the conical lower surface 516 tapers from the mounting flange 152 to the first intermediate portion 504. Still in the illustrated embodiment, the output shaft 104 further includes one or more lubrication conduits 518 which extend through the first end portion 500, from the conical lower surface 516 to the bottom wall 512 of the inner recess 510, to allow lubricating fluid to be provided in the inner recess 510. Alternatively, instead of being conical, the lower surface 516 could extend in a plane perpendicular to the longitudinal shaft axis Li .

Referring now to FIGS. 1 and 5, the output shaft 104 is further configured to be received within an output shaft holding assembly 160 which maintains the output shaft 104 in alignment with the longitudinal shaft axis Li while allowing the output shaft 104 to rotate about the longitudinal shaft axis Li . In the illustrated embodiment, the output shaft holding assembly 160 includes a first roller bearing 162 mounted around the first intermediate portion 504 of the output shaft 104 and abutting the first end portion 500, a retaining ring 164 mounted around the second end portion 502 and abutting the second intermediate portion 506 and a second roller bearing 166 mounted around the second intermediate portion 506 and abutting the retaining ring 164. The first and second roller bearings 162, 166 and the retaining ring 164 may be secured to the housing or to another structure such as a frame or a bracket assembly which is distinct from the housing.

Still in the illustrated embodiment, the output shaft 104 further includes a connection interface 170 for operatively connecting the speed reducer 100 directly to a driven rotating device or machine or indirectly to the driven rotating device or machine via a shaft extension. Specifically, the connection interface 170 includes a keyway 172 defined in the output shaft 104 and extending from the second end 1 14 towards the first end 1 12 of the output shaft 104. The keyway 172 is generally parallel to the longitudinal shaft axis Li and is configured for receiving a corresponding key, not shown.

In one embodiment, the output shaft 104 further includes a threaded bore 174 extending from the second end 1 14 towards the first end 1 12 of the output shaft 104, generally parallel to the longitudinal shaft axis Li . The threaded bore 174 is adapted to threadably receive a threaded tool to allow the output shaft 104 to be moved along the longitudinal shaft axis Li for installation and/or removal or to be otherwise manipulated. The threaded bore 174 could further be configured to receive a drive coupling accessory or to be connected to a drive coupling connected to a rotatable shaft of a device to reinforce the drive coupling connection between the reducer 100 and the device.

When the speed reducer 100 is properly assembled and ready for operation, the output flange 142 is fastened to the output shaft 104. More specifically, the mounting flange 152 of the output shaft 104 is received in the mounting recess 212 of the output flange 142 and the rim projection 508 of the output shaft 104 is received in the central flange opening 210. In this configuration, the output flange 142 is generally orthogonal to the longitudinal shaft axis Li . The output flange 142 is further oriented relative to the mounting flange 152 such that each fastener bore 222 of the output flange is in alignment with a corresponding mounting hole 404 of the mounting flange 152. The mounting fasteners are inserted through the mounting holes 404 and into the fastener bores 222, and thereby prevent the output flange 142 from moving or rotating relative to the output shaft 104. The output flange 142 is thereby removably fastened to the mounting flange 152.

Still when the speed reducer 100 is properly assembled and ready for operation, the output shaft 104 is further received within the output shaft holding assembly 160 and the pins 144 of the output flange 142 operatively engage the circular pin openings 146 of the first and second cycloidal discs 1 18, 120.

When the pins 144 or the flange body 200 of the output flange 142 become worn or damaged, the entire output assembly 140 may be removed from the speed reducer 100 and the output flange 142 may be replaced without having to replace the output shaft 104. More specifically, the output shaft 104 and the output flange 142 may be removed from the output shaft holding assembly 160 and from the housing. The output flange 142 may then be unfastened from the mounting flange 152 by removing the mounting fasteners, and the output flange 142 can be removed from the output assembly 140.

A replacement output flange, similar to the output flange 142, may then be provided. The replacement output flange may be fastened to the mounting flange 152 of the output shaft 104, as detailed above. The output assembly 140 can then be installed again in the speed reducer 100 and operation of the speed reducer 100 can resume.

Similarly, if the output shaft 104 becomes worn or damaged, the output assembly 140 can be removed from the speed reducer 100, the output shaft 104 can be unfastened from the output flange 142 and removed, a replacement output shaft can be provided, the replacement output shaft can be fastened to the output flange 142 and the output assembly 140 can be installed again in the speed reducer 100.

It will be appreciated that providing the output assembly 140 as two distinct elements, i.e. the output shaft 104 and the output flange 142, removably fastened to each other rather than a single, monolithic part eliminates the need to replace the entire output assembly 140 if only one of the output shaft 104 and the output flange 142 becomes worn or damaged and requires replacement. This may reduce the costs of the parts and labour associated with the replacement.

It will also be appreciated that the flange connection assembly 150 may have one of various alternative configurations. For example, the flange connection assembly 150 could include an output flange having a cylindrical sleeve portion extending over the first end portion 500 of the output shaft 104. In this alternative configuration, the output flange could be fastened to the output shaft 104 using one or more mounting fasteners extending through the sleeve and into the first end portion 500 of the output shaft 104, transversely to the longitudinal shaft axis Li . Alternatively, the flange connection assembly 150 could include any connection assembly adapted to removably fasten the output flange 142 to the output shaft 104 which a skilled person would consider to be suitable. In one embodiment, the flange connection assembly 150 could even include a connection made by welding the output flange 142 to the output shaft 104. In this case, the output flange 142 could be detached from the output shaft 104 by breaking, melting or otherwise removing the weld between the output flange 142 and the output shaft 102.

In one embodiment, the input shaft 102 includes a tapered shaft portion 180 which is configured to be received in the eccentric cam member 1 16. This configuration contributes to preventing axial movement of the eccentric cam member 1 16 relative to the input shaft 102. This configuration may also create further friction between the eccentric cam member 1 16 and the input shaft 102 to further prevent the eccentric cam member 1 16 from rotating relative to the input shaft 102.

Referring to FIGS. 1 and 6, the input shaft 102 includes a first end portion 600 extending from the first end 108 towards the second end 1 10 of the input shaft 102 and a second end portion 602 extending from the second end 1 10 towards the first end 108 of the input shaft 102. The tapered shaft portion 180 extends between the first and second end portions 600, 602. Specifically, the tapered shaft portion 180 includes a first end 604 located towards the first end 108 of the input shaft and a second end 606 located towards the second end 1 10 of the input shaft 102. In this configuration, the first end 604 is located towards the output shaft 104 and the second end 606 is located away from the output shaft 104.

As best shown in FIG. 6, the tapered shaft portion 180 tapers from the second end 606 to the first end 604 such that the first end 604 has a first diameter and the second end 606 has a second diameter which is larger than the first diameter.

Still in the illustrated embodiment, the input shaft 102 further includes a tapered portion keyway 608 extending generally parallel to the longitudinal shaft axis Li of the input shaft 102. The tapered portion keyway 608 is adapted to receive a key, not shown, which engages the eccentric cam member 1 16 when the tapered shaft portion 180 is received in the eccentric cam member 1 16 to prevent the eccentric cam member 1 16 from rotating relative to the input shaft 102, as well as to transfer torque from the input shaft 102 to the eccentric cam member 1 16. In the illustrated embodiment, the tapered portion keyway 608 is elongated and extends generally along the entire length of the tapered shaft portion 180, between the first end 604 and the second end 606 of the tapered shaft portion 180. Alternatively, the tapered portion keyway 608 could instead be shorter than the tapered shaft portion 180.

Still in the illustrated embodiment, the tapered portion keyway 608 is generally straight to receive a generally straight key. Alternatively, if the key is wedge- shaped, then the tapered portion keyway 608 may be angled.

In the illustrated embodiment, the tapered shaft portion 180 has a length of about 3.446 inches or about 8.7528 cm, the first end 604 of the tapered shaft portion 180 has a diameter of about 2.401 1 inches or 6.0988 cm and the second end 606 of the tapered shaft portion 180 has a diameter of about 2.5806 inches or 6.5547 cm. In this configuration, the tapered shaft portion 180 may have a taper angle of about 1 .4916 degrees. Alternatively, the tapered shaft portion 180 could have different dimensions considered to be appropriate by a skilled person.

Still referring to FIGS. 1 and 6, the first end portion 600 of the input shaft 102 is generally cylindrical and has the same diameter as the first end 604 of the tapered shaft portion 180. Alternatively, the first end portion 600 may have a greater or smaller diameter than the first end 604 of the tapered shaft portion 180. In yet another embodiment, the input shaft 102 may not include a first end portion and the tapered shaft portion 180 may instead extend to the first end 108 of the input shaft 102.

In the illustrated embodiment, the second end portion 602 includes a plurality of adjacent shaft end sections 610 having different diameters and a shoulder 612 located near the second end 606 of the tapered shaft portion 180 between the tapered shaft portion 180 and the plurality of adjacent shaft end sections 610. Alternatively, the second end portion 602 may not include a plurality of adjacent shaft end sections having different diameters and/or a shoulder.

Still in the illustrated embodiment, the second end portion 602 is configured to be received in an input shaft holding assembly 190 which maintains the input shaft 102 in alignment with the longitudinal shaft axis Li while allowing the input shaft 102 to rotate about the longitudinal shaft axis Li . In the illustrated embodiment, the input shaft holding assembly 190 includes a retaining ring 192 disposed around the second end portion 602 and a roller bearing 194 sandwiched between the shoulder 612 and the retaining ring 192. Similarly to the output shaft holding assembly 160, the roller bearing 194 and the retaining ring 192 may be secured to the housing or to another structure such as a frame or a bracket assembly which is distinct from the housing.

Still in the illustrated embodiment, the input shaft 102 further includes a threaded bore 614 which extends from the first end 108 of the input shaft 102 through the first end portion 600 and partially into the tapered shaft portion 180. The threaded bore 614 may be used to fasten a cap member 196, shown in FIG. 1 , to the first end 108 of the input shaft 102. The input shaft 102 further includes a fluid passageway 616 which extends from the threaded bore 614 to the tapered portion keyway 608 and thereby allows fluid communication between the threaded bore 614 and the tapered portion keyway 608. In this configuration, the cap member 196 could be removed and a fluid could be injected into the tapered portion keyway 608 through the threaded bore 614 and the fluid passageway 616 to dislodge the key received in the tapered portion keyway 608. The force applied by the fluid on the key may further be useful to separate the eccentric cam member 1 16 from the input shaft 102 when the eccentric cam member 1 16 is mounted on the tapered shaft portion 180 of the input shaft 102. In one embodiment, the fluid may be pressurized to exert on the key a force sufficient to dislodge the key from the tapered portion keyway 608 and/or to separate the eccentric cam member 1 16 from the input shaft 102.

In the illustrated embodiment, the reducer 100 further includes a tubular space sleeve 198 which is disposed around the first end portion 600 of the input shaft 102 and which abuts the eccentric cam member 1 16. Still in the illustrated embodiment, the cap member 196 has a diameter which is slightly larger than the first end portion 600 of the input shaft 102 to hold the bearing 154 against the spacer sleeve 198. Alternatively, the spacer sleeve 198, the cap member 196 and the first end portion 600 may have a different configuration.

Referring now to FIGS. 1 , 7 and 8, the eccentric cam member 1 16 includes a cam body 700 having a first cylindrical portion 702 and a second cylindrical portion 704. More specifically, each cylindrical portion 702, 704 includes opposite first and second ends 706, 708, and the first and second cylindrical portions 702, 704 respectively define a first cam longitudinal axis Ci and a second cam longitudinal axis C2. As best shown in FIG. 8, the first and second cylindrical portions 702, 704 are disposed side-by-side such that the second end 708 of the first cylindrical portion 702 is adjacent the first end 706 of the second cylindrical portion 704 and such that the first and second cam longitudinal axes C1 , C2 are parallel to each other. As shown in FIG. 7, the first and second cylindrical portions 702, 704 are not disposed coaxially to each other but are instead offset relative to each other. Specifically, the eccentric cam member 1 16 further includes a shaft bore 710 which extends through the cam body 700 between the first end 706 of the first cylindrical portion 702 and the second end 708 of the second cylindrical portion 704. The shaft bore 710 defines a shaft bore longitudinal axis C3 which is spaced from both the first cam longitudinal axis C1 and the second cam longitudinal axis C2.

In this configuration, the shaft bore 710 is therefore offcentered relative to both the first cylindrical portion 702 and the second cylindrical portion 704. Specifically, the first cam longitudinal axis C₁ and the second cam longitudinal axis C₂ are symmetrically offset from the shaft bore longitudinal axis C3 in opposite radial directions, such that the first and second longitudinal axes C1 , C2 and the shaft bore longitudinal axis C3 all extend along a common plane, as best shown in FIG. 7. It will be appreciated that this configuration contributes to balancing the radial loads applied on the input shaft 102 resulting from the eccentric movement of the first and second cycloidal discs 1 18, 120 about the input shaft 102. In an alternative embodiment, the eccentric cam member 1 16 may not include the second cylindrical portion 704, but only include a single cylindrical portion, in which case the reducer 100 would also include a single cycloidal disc 1 18 or 120.

In the illustrated embodiment, the shaft bore 710 is not cylindrical but is instead tapered. More specifically, the shaft bore 710 includes a generally conical inner sidewall 712 having a first end 714 which has a first end diameter and a second end 716 which has a second end diameter which is larger than the first end diameter. In one embodiment, the shaft bore 710 has a length of about 3.4480 inches or about 8.7579 cm, the first end 714 of the shaft bore 710 has a first end diameter of about 2.3947 inches or 6.0825 cm and the second end 716 of the shaft bore 710 has a second end diameter of about 2.5743 inches or 6.5387 cm. In this configuration, the shaft bore 710 may have a taper angle of about 1 .4916 degrees, which corresponds to the taper angle of the tapered shaft portion 180. Alternatively, the shaft bore 710 could have different dimensions that a skilled person would considered to be appropriate. For example, the taper angle could be greater or less than 1 .4916 degrees.

Still referring to FIGS. 1 , 7 and 8, the cam body 700 further includes a cam member keyway 720 defined in the inner sidewall 712 of the shaft bore 710. The cam member keyway 720 is elongated and extends generally parallel to the shaft bore longitudinal axis C3 along the entire length of the shaft bore 710, between the first end 714 and the second end 716 of the shaft bore 710. The cam member keyway 720 is generally similar to the tapered portion keyway 608 of the input shaft 102 and is adapted to receive the same key which is received in the tapered portion keyway 608. In the illustrated embodiment, the cam member keyway 720 is generally straight to receive a generally straight key. Alternatively, if the key is wedge-shaped, then the cam member keyway 720 may be angled. When the key is received in both the tapered portion keyway 608 and the cam member keyway 720, the key prevents the eccentric cam member 1 16 from rotating relative to the input shaft 102.

In one embodiment, each one of the first and second cylindrical portions 702, 704 could be manufactured separately and the first and second cylindrical portions 702, 704 could then be assembled together to form the eccentric cam member 1 16. Alternatively, the eccentric cam member 1 16 could be manufactured as a single, unitary piece.

To mount the eccentric cam member 1 16 to the input shaft 102, the first end 108 of the input shaft 102 is inserted into the shaft bore 710 through the second end 716 of the shaft bore 710, through the shaft bore 710 and out the first end 714 of the shaft bore 710. The input shaft 102 and the eccentric cam member 1 16 are further oriented relative to each other such that the tapered portion keyway 608 and the cam member keyway 720 are aligned with each other, and the key is inserted in the tapered portion keyway 608 and the cam member keyway 720 to thereby lock the input shaft 102 and the eccentric cam member 1 16 in rotation relative to each other.

It will be appreciated that in this position, the tapered shaft portion 180 sits against the inner sidewall 712 of the shaft bore 710 since the tapered shaft portion 180 and the shaft bore 710 are tapered at the same taper angle. In addition to being locked in rotation, this configuration further prevents the eccentric cam member 1 16 from further moving along the longitudinal shaft axis Li towards the second end 1 10 of the input shaft 102.

Moreover, the eccentric cam member 1 16 may be forced towards the second end 1 10 of the input shaft 102 such that the eccentric cam member 1 16 becomes wedged on the tapered shaft portion 180, thereby creating a press fit-type connection between the eccentric cam member 1 16 and the tapered shaft portion 180. Therefore, by combining the effect of the press fit-type connection with the key to lock the eccentric cam member 1 16 in rotation with the input shaft 102, the present configuration may generally reduce wear on the key and thereby extend the life of the key. This in turn reduces the risk of the speed reducer 100 becoming damaged and requiring repairs. It will be appreciated that the speed reducer 100 illustrated and described above is merely provided as an example, and that many variations are possible. For example, instead of having first and second cycloidal discs, the speed reducer could include a single cycloidal disc, or any number of cycloidal discs which a skilled person would consider to be appropriate.

In one embodiment, the input shaft 102 and the eccentric cam member 1 16 could be provided as an input kit to allow a user to retrofit an existing cycloidal speed reducer. Specifically, the existing cycloidal speed reducer includes a non-tapered input shaft which includes only cylindrical portions and no tapered shaft portions. In this embodiment, the existing cycloidal speed reducer further includes a non- tapered eccentric cam member which includes a cylindrical shaft bore sized and shaped to receive one of the cylindrical portions of the non-tapered input shaft. Still in this embodiment, the input shaft 102 and the eccentric cam member 1 16, configured as described above, would first be assembled together by the user. The non-tapered input shaft and the non-tapered eccentric cam member could be removed from the existing cycloidal speed reducer and replaced by the input shaft 102 with the eccentric cam member 1 16 mounted on the input shaft 102 to thereby provide the existing cycloidal speed reducer with at least some of the advantages of the speed reducer 100 as described above.

In one embodiment, the output assembly 140 including the output shaft 104 and the output flange 142 fastenable to the output shaft 104 could also be provided as an output kit to allow a user to retrofit an existing cycloidal speed reducer. Specifically, the existing cycloidal speed reducer includes a monolithic output assembly having an output shaft and an output flange which are integrally formed together. In this embodiment, the output flange 142 would first be fastened to the output shaft 104 using the mounting fasteners as described above. The monolithic output assembly could be removed from the existing cycloidal speed reducer and replaced by the output shaft 104 with the output flange 142 fastened to the output shaft 104 to thereby provide the existing cycloidal speed reducer with at least some of the advantages of the speed reducer 100 as described above.

Turning now to FIG. 9, there is further provided a method 900 for retrofitting an existing cycloidal speed reducer, in accordance with one embodiment. The existing cycloidal speed reducer may be generally similar to the speed reducer 100 described above, except that the existing cycloidal speed reducer includes a monolithic output assembly having an output shaft and an output flange which are integrally formed together.

In one embodiment, the existing cycloidal speed reducer may also include a non- tapered input shaft which includes only cylindrical portions and no tapered shaft portions. In this embodiment, the existing cycloidal speed reducer further includes a non-tapered eccentric cam member which includes a cylindrical shaft bore sized and shaped to receive one of the cylindrical portions of the non-tapered input shaft.

According to 902, the monolithic output assembly is removed from the existing cycloidal speed reducer. It will be understood that this step may involve additional operations such as removing the output shaft holding assembly from the housing, or any other additional operation which a skilled person would consider to be appropriate.

According to 904 and 906, the output shaft 104 and the output flange 142, configured as described above, are provided. In one embodiment, one or both of the output shaft 104 and the output flange 142 may be manufactured from an existing monolithic output assembly. Specifically, one or both of the output shaft 104 and the output flange 142 may be manufactured by cutting, machining or otherwise modifying the monolithic output assembly removed from the existing cycloidal speed reducer in step 902 above.

According to 908, the output flange 142 is fastened on the output shaft 104 using the mounting fasteners, as described above, to form the output assembly 140.

According to 910, the output assembly 140 is then installed in the existing cycloidal speed reducer. Specifically, the output assembly 140 is disposed such that the output shaft 104 is received in the output shaft holding assembly 160 and extends along the longitudinal shaft axis Li , and the pins 144 of the output flange 142 are received in the corresponding pin openings 146 of the first and second cycloidal discs 1 18, 120. The existing cycloidal speed reducer is now retrofitted such that it may benefit from at least some of the advantages of the speed reducer 100 as described above.

According to 912, the non-tapered input shaft and the non-tapered eccentric cam member may also be removed from the existing cycloidal speed reducer. It will be understood that this step may involve additional operations such as removing the input shaft holding assembly from the housing, or any other additional operation which a skilled person would consider to be appropriate.

According to 914 and 916, the input shaft 102 including the tapered shaft portion 180 and the eccentric cam member 1 16 including the tapered shaft bore 710 may be provided.

According to 918, the eccentric cam member 1 16 may be mounted on the input shaft 102 as described above. According to 920, the input shaft 102 with the eccentric cam member 116 mounted on the input shaft 102 may now be installed in the existing cycloidal speed reducer. Specifically, the input shaft 102 is disposed such that it extends along the longitudinal shaft axis Li and the first and second eccentric discs 118, 120 are mounted on the eccentric cam member 116 via bearings 126 as described above. The existing cycloidal speed reducer is now further retrofitted such that it may benefit from at least some of the advantages of the speed reducer 100 as described above.

It will be appreciated that the method described above is merely provided as an example, and that other embodiments of a method for retrofitting an existing cycloidal speed reducer may be provided.

Claims

1. A cycloidal speed reducer comprising:

a rotatable input shaft;

a rotatable output shaft; and

a transmission assembly operatively connecting the input shaft to the output shaft for transmitting rotation of the input shaft rotating at an input rotation speed to the output shaft, the transmission assembly including:

an eccentric cam member mounted on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being sized and shaped to receive the input shaft therein, the shaft bore further being offcentered relative to the at least one cylindrical portion; at least one cycloidal disc, each cycloidal disc including a circular disc body having a central opening for rotatably receiving a corresponding cylindrical portion of the eccentric cam member such that rotation of the input shaft moves the cycloidal disc along a circular path, each cycloidal disc further having at least one circular pin opening spaced radially outwardly from the central opening and a plurality of teeth extending radially outwardly from the disc body;

a plurality of teeth members disposed annularly around the at least one cycloidal disc, the teeth members being sized and shaped for meshingly engaging the plurality of teeth of a corresponding cycloidal disc to rotate the cycloidal disc as it moves along the circular path; and an output flange distinct from the output shaft and removably attached to the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed.

2. The speed reducer as claimed in claim 1 , wherein the input shaft defines an input shaft axis and the output shaft defines an output shaft axis, the input and output shafts being disposed such that the input shaft axis and the output shaft axis extend parallel to each other.

3. The speed reducer as claimed in claim 2, wherein the input shaft and the output shaft are coaxial with each other.

4. The speed reducer as claimed in any one of claims 1 to 3, further including a flange connection assembly for removably connecting the driven flange to the output shaft.

5. The speed reducer as claimed in claim 4, wherein the flange connection assembly includes a mounting flange extending radially outwardly from the output shaft and a plurality of mounting fasteners configured for extending through the mounting flange and the output flange to removably fasten the output flange to the mounting flange.

6. The speed reducer as claimed in claim 5, wherein the output flange includes a circular flange body having a first face and a second face located opposite the first face, the at least one output pin extending generally orthogonally from the first face and away from the first face.

7. The speed reducer as claimed in claim 6, wherein the at least one output pin includes a plurality of output pins disposed annularly on the first face of the flange body.

8. The speed reducer as claimed in any one of claims 6 and 7, wherein the output flange further includes a circular mounting recess defined in the flange body on the second face thereof, the circular mounting recess being sized and shaped to receive the mounting flange.

9. The speed reducer as claimed in claim 8, wherein the flange includes a plurality of mountings holes disposed annularly in the circular mounting recess, the mounting holes being sized and shaped to receive the mounting fasteners.

10. The speed reducer as claimed in claim 9, wherein each mounting hole is threaded.

1 1 . The speed reducer as claimed in any one of claims 8 and 9, wherein the plurality of mounting holes includes twelve mounting holes evenly distributed in a circular pattern around the central opening.

12. The speed reducer as claimed in any one of claims 8 to 1 1 , wherein the flange body is annular and has an outer circular edge and an inner circular edge defining a central flange opening, the circular mounting recess extending from the inner circular edge radially towards the outer edge.

13. The speed reducer as claimed in claim 12, wherein the output shaft includes a tubular rim projection extending away from the mounting flange, the tubular rim projection being sized and shaped to be snuggly received in the central opening of the output flange when the mounting flange is received in the circular mounting recess.

14. The speed reducer as claimed in any one of claims 1 to 13, wherein the eccentric cam member includes a first cylindrical portion and a second cylindrical portion, the first and second cylindrical portions being offset relative to each other.

15. The speed reducer as claimed in claim 14, wherein the at least one cycloidal disc includes a first cycloidal disc and a second cycloidal disc parallel to and spaced apart from the first cycloidal disc, the first cylindrical portion of the eccentric cam member being rotatably received in the first cycloidal disc and the second cylindrical portion being rotatably received in the second cycloidal disc.

16. The speed reducer as claimed in any one of claims 1 to 15, wherein the input shaft includes a tapered shaft portion and the shaft bore further being tapered to snuggly receive the tapered shaft portion.

17. An output assembly for a cycloidal speed reducer, the speed reducer including a rotatable input shaft, an eccentric cam member mounted on the input shaft and at least one cycloidal disc rotatably mounted to one of at least one cylindrical portion of the eccentric cam member, the at least one cycloidal disc being offcentered relative to the input shaft such that rotation of the input shaft moves the at least one cycloidal disc along a circular path, the speed reducer further including a plurality of teeth members disposed annularly around the at least one cycloidal disc and the at least one cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the at least one cycloidal disc further including at least one circular pin opening, the output assembly comprising:

a rotatable output shaft; and

an output flange distinct from the output shaft and removably attached to the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the at least one cycloidal disc such that movement of the cycloidal disc along the eccentric cycloidal path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed.

18. The output assembly as claimed in claim 17, further including a flange connection assembly for removably connecting the driven flange to the output shaft.

19. The output assembly as claimed in claim 18, wherein the flange connection assembly includes a mounting flange extending radially outwardly from the output shaft and a plurality of mounting fasteners configured for extending through the mounting flange and the output flange to removably fasten the output flange to the mounting flange.

20. The output assembly as claimed in claim 19, wherein the output flange includes a circular flange body having a first face and a second face located opposite the first face, the at least one output pin extending generally orthogonally from the first face and away from the first face.

21 . The output assembly as claimed in claim 20, wherein the at least one output pin includes a plurality of output pins disposed annularly on the first face of the flange body.

22. The output assembly as claimed in any one of claims 20 and 21 , wherein the output flange further includes a circular mounting recess defined in the flange body on the second face thereof, the circular mounting recess being sized and shaped to receive the mounting flange.

23. The output assembly as claimed in claim 22, wherein the flange includes a plurality of mountings holes disposed annularly in the circular mounting recess, the mounting holes being sized and shaped to receive the mounting fasteners.

24. The output assembly as claimed in claim 23, wherein each mounting hole is internally threaded.

25. The output assembly as claimed in any one of claims 23 and 24, wherein the plurality of mounting holes includes twelve mounting holes evenly distributed in a circular pattern around the central opening.

26. The output assembly as claimed in any one of claims 22 to 25, wherein the flange body is annular and has an outer circular edge and an inner circular edge defining a central flange opening, the circular mounting recess extending from the inner circular edge radially towards the outer edge.

27. The output assembly as claimed in claim 26, wherein the output shaft includes a tubular rim projection extending away from the mounting flange, the tubular rim projection being sized and shaped to be snuggly received in the central opening of the output flange when the mounting flange is received in the circular mounting recess.

28. A cycloidal speed reducer comprising: a rotatable input shaft having a tapered shaft portion;

a rotatable output shaft; and

an eccentric cam member mounted on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft;

at least one cycloidal disc, each cycloidal disc including a circular disc body having a central opening for rotatably receiving a corresponding cylindrical portion of the eccentric cam member such that rotation of the input shaft moves the cycloidal disc along a circular path, each cycloidal disc further having at least one circular pin opening spaced radially outwardly from the central opening and a plurality of teeth extending radially outwardly from the disc body;

a plurality of teeth members disposed annularly around the at least one cycloidal disc, the teeth members being sized and shaped for meshingly engaging the plurality of teeth of a corresponding cycloidal disc to rotate the cycloidal disc as it moves along the circular path; and an output flange extending radially outwardly from the output shaft, the output flange including at least one output pin extending into a corresponding pin opening of the cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed.

29. The speed reducer as claimed in claim 28, wherein the tapered shaft portion includes a first end having a first diameter and a second end having a second diameter larger than the first diameter, the first end being disposed towards the output shaft and the second end being disposed away from the output shaft.

30. The speed reducer as claimed in any one of claims 28 and 29, wherein the input shaft includes an elongated key defined on the tapered shaft portion and extending parallel to a longitudinal axis of the input shaft, and the eccentric cam member includes a corresponding keyway defined in the shaft bore for receiving the key to prevent rotation of the input shaft relative to the eccentric cam member.

31 . The speed reducer as claimed in any one of claims 28 to 30, wherein both the tapered input shaft portion and the shaft bore are tapered at a taper angle of 1 .4916 degrees.

32. The speed reducer as claimed in any one of claims 28 to 31 , wherein the output flange is distinct from the output shaft and removably attached thereto.

33. A method for retrofitting an existing cycloidal speed reducer, the existing cycloidal speed reducer including a rotatable non-tapered input shaft, a rotatable monolithic output assembly and a non-tapered eccentric cam member mounted on the non-tapered input shaft, the non-tapered eccentric cam member having a non- tapered shaft bore sized and shaped to receive the non-tapered input shaft therein, the existing cycloidal speed reducer further including at least one cycloidal disc mounted to at least one cylindrical portion of the eccentric cam member, the at least one cycloidal disc being offcentered relative to the non-tapered input shaft such that rotation of the non-tapered input shaft moves the at least one cycloidal disc along a circular path, the existing cycloidal speed reducer further including a plurality of teeth members disposed annularly around the at least one cycloidal disc and the at least one cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the at least one cycloidal disc further including at least one circular pin opening, the kit comprising:

removing the monolithic output assembly;

providing a rotatable output shaft;

providing an output flange distinct from the output shaft and removably attachable to the output shaft, the output flange including at least one output pin configured for extending into a corresponding pin opening of the at least one cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed;

removably attaching the output flange to the output shaft to thereby form an outlet assembly;

installing the output assembly in the speed reducer.

34. The method as claimed in claim 33, further comprising: removing the non-tapered input shaft and the non-tapered eccentric cam member from the existing cycloidal speed reducer;

providing a rotatable input shaft having a tapered shaft portion;

providing an eccentric cam member mountable on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft;

mounting the eccentric cam member on the tapered shaft portion of the input shaft;

installing the input shaft with the eccentric cam mounted thereon in the speed reducer.

35. A kit for retrofitting an existing cycloidal speed reducer, the existing cycloidal speed reducer including a rotatable non-tapered input shaft, a rotatable monolithic output assembly and a non-tapered eccentric cam member mounted on the non- tapered input shaft, the non-tapered eccentric cam member having a non-tapered shaft bore sized and shaped to receive the non-tapered input shaft therein, the existing cycloidal speed reducer further including at least one cycloidal disc mounted to at least one cylindrical portion of the eccentric cam member, the at least one cycloidal disc being offcentered relative to the non-tapered input shaft such that rotation of the non-tapered input shaft moves the at least one cycloidal disc along a circular path, the existing cycloidal speed reducer further including a plurality of teeth members disposed annularly around the at least one cycloidal disc and the at least one cycloidal disc including a plurality of teeth configured for meshing with the teeth members disposed around the cycloidal disc, the at least one cycloidal disc further including at least one circular pin opening, the kit comprising:

a rotatable output shaft;

an output flange distinct from the output shaft and removably attachable to the output shaft, the output flange including at least one output pin configured for extending into a corresponding pin opening of the at least one cycloidal disc such that rotation and movement of the cycloidal disc along the circular path urges rotation of the output shaft at an output rotation speed lower than the input rotation speed;

a rotatable input shaft having a tapered shaft portion; and an eccentric cam member mountable on the input shaft, the eccentric cam member having a cam body including at least one cylindrical portion and a shaft bore extending through the cam body, the shaft bore being offcentered relative to the at least one cylindrical portion, the shaft bore further being tapered to snuggly receive the tapered shaft portion of the input shaft.