WO2015039231A1

WO2015039231A1 - Drive assembly provided with a continuously variable transmission and a direction reversing mechanism

Info

Publication number: WO2015039231A1
Application number: PCT/CA2014/050871
Authority: WO
Inventors: Daniel Girard; Jean-François DIONNE
Original assignee: Transmission Cvtcorp Inc.
Priority date: 2013-09-20
Filing date: 2014-09-15
Publication date: 2015-03-26

Abstract

A drive assembly including a CVT and a direction reversing mechanism is described herein. Accordingly, the direction of rotation of the output shaft of the drive assembly may be changed via the direction reversing mechanism.

Description

TITLE

Drive assembly provided with a Continuously Variable Transmission and a direction reversing mechanism.

FIELD

[0001] The present disclosure generally relates to drive assemblies provided with a Continuously Variable Transmission (hereinafter referred to as a CVT). More specifically, the present disclosure is concerned with such a drive assembly also provided with a direction reversing mechanism.

BACKGROUND

[0002] CVTs are well known in the art. They generally transform a fixed speed input into a variable speed output.

[0003] Without further mechanical elements, the variable speed output of the CVT in a fixed direction with respect to the CVT input.

[0004] It is generally mechanically complicated to provide a mechanism allowing the direction of the variable speed output of the CVT to be reversible.

BRIEF DESCRIPTION OF THE DRAWINGS [0005] In the appended drawings:

[0006] Figure 1 is a schematic view of a drive assembly according to a first illustrative embodiment; the drive assembly being shown in a neutral position; [0007] Figure 2 is a schematic view of the drive assembly of Figure

1 , shown in a position where the output shaft rotates in a first direction;

[0008] Figure 3 is a schematic view of the drive assembly of Figure

1 , shown in a position where the output shaft rotates in a second direction;

[0009] Figure 4 is a schematic view of a drive assembly according to a second illustrative embodiment, shown in a neutral position; and

[0010] Figure 5 is a schematic view of a drive assembly according to a third illustrative embodiment, shown in a neutral position.

DETAILED DESCRIPTION

[0011] An object is generally to provide an improved drive assembly.

More specifically, an object is to provide a drive assembly provided with a CVT and a direction reversing mechanism.

[0012] The use of the word "a" or "an" when used in conjunction with the term "comprising" in the claims and/or the specification may mean "one", but it is also consistent with the meaning of "one or more", "at least one", and "one or more than one". Similarly, the word "another" may mean at least a second or more.

[0013] As used in this specification and claim(s), the words

"comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "include" and "includes") or "containing" (and any form of containing, such as "contain" and "contains"), are inclusive or open-ended and do not exclude additional, unrecited elements or process steps.

[0014] The term "about" is used to indicate that a value includes an inherent variation of error for the device or the method being employed to determine the value.

[0015] It is to be noted that while the expression "CVT", standing for

Continuously Variable Transmission is used herein to refer to an illustrated a dual-cavity full toroidal CVT. However, this expression is to be construed herein and in the appended claims as any type of toroidal CVT such as, for example, half-toroidal CVT and single cavity toroidal CVT. Other objects, advantages and features of the drive assembly provided with a CVT and a direction reversing mechanism will become more apparent upon reading of the following non-restrictive description of illustrative embodiments thereof, given by way of example only with reference to the accompanying drawings.

[0016] Generally stated, illustrative embodiments illustrated herein are concerned with a drive assembly including a CVT and a direction reversing mechanism. Accordingly, the direction of rotation of the output shaft of the drive assembly may be changed at will.

[0017] Turning now to Figure 1 , a drive assembly 10 according to a first illustrative embodiment is schematically illustrated. The drive assembly 10 includes a CVT 12, a direction reversing mechanism 14 and a separating wall 16. Of course, these elements are conventionally contained in a casing (not shown). [0018] The CVT 12 illustrated in Figure 1 is a dual-cavity toroidal

CVT which is provided with two drive disks 18, 20 having a toroidal surface and being so mounted to an input shaft 21 as to rotate therewith. A driven disk 22 having opposite toroidal surfaces respectively facing the drive disks 18 and 20 and rotatably mounted to the input shaft 21 is also provided. The three disks 18, 20 and 22 are linked by rollers 24, 26 in contact with their respective toroidal surfaces. Conventionally, the angle of the rollers with respect to the drive and driven disks dictates the speed ratio between the driven and drive disks. The CVT 12 is also provided with an output drum 28 associated with the driven disk 22 and provided with an output shaft 30 coaxial with the input shaft 21 .

[0019] The input shaft 21 and the output shaft 30 of the CVT 12 may respectively be viewed as the input and the output of the CVT 12.

[0020] One skilled in the art will understand that the CVT 12 is schematically illustrated herein and that other elements not shown herein are present in the CVT 12.

[0021] The direction reversing mechanism 14 includes a first shaft

32 connected to the output shaft 30; a first bevel gear 34 rotatably mounted to the first shaft 32; a second bevel gear 36 rotatably mounted to the first shaft 32; a third bevel gear 38 meshed with both the first and second bevel gears 34, 36 and so mounted to a second shaft 40 as to rotate therewith; and a bevel gear selection mechanism including a three-position clutch flange 42 so mounted to a splined portion of the first shaft 32 as to be axially movable thereon while rotating therewith. [0022] As will be apparent to one skilled in the art, a dog clutch assembly is illustrated in the appended figures. However, other types of clutches can be used.

[0023] The bevel gear selection mechanism also includes an actuator (not shown) used to axially move the flange 42 onto the splined portion of the shaft 32 (see double arrow 44). As non-limiting examples, a conventional fork actuator or a solenoid-type actuator could be used. Of course, other types of actuators could be used.

[0024] It is to be noted that the first shaft 32 and the output shaft 30 could be integral.

[0025] As can be seen from Figure 1 , the first and second bevel gears 34, 36 respectively include teeth 46, 48 so configured and sized as to mesh with respective teeth 50, 52 of the dog clutch flange 42 as will be described hereinbelow.

[0026] A separation wall 16 is provided between the CVT 12 and the direction reversing mechanism 14. One of the reasons of having such a separating wall is to prevent contamination of the traction oil present in the CVT 12 by the oil potentially containing metal particles present in the direction reversing mechanism 14. Indeed, these oil compositions may be different and the mechanical interactions present in the direction reversing mechanism 14 tend to generate metal particles that could be detrimental to the life expectancy of the CVT 12.

[0027] It is to be noted that in some instances, for example if adequate filtration is used and if the traction oil and the oil of the direction reversing mechanism are the same composition, the wall 16 can be omitted from the drive assembly 10.

[0028] One skilled in the art will understand that the direction reversing mechanism 14 is schematically illustrated herein and that other elements not shown herein are present in the direction reversing mechanism 14.

[0029] Turning now to Figures 1 to 3 of the appended drawings, the operation of the drive assembly 10 will be described.

[0030] In Figure 1 , the flange 42 of the bevel gear selection mechanism is in a neutral position. Accordingly, even though the first shaft 32 rotates via its interconnection with the output shaft 30 of the CVT 12, the output shaft 40 of the bevel gear selection mechanism does not rotate.

[0031] Figure 2 illustrates the direction reversing mechanism in a first position. As can be shown by arrow 54, the flange 42 has been actuated so that there is an interconnection between the teeth 46 of the first bevel gear 34 and the teeth 50 of the flange 42. Accordingly, rotation of the first shaft 32 (see arrow 56) causes the rotation of the second shaft 40 in a first direction (see arrow 58).

[0032] It will be apparent to one skilled in the art that a synchronization scheme may be provided to facilitate the interconnection between the teeth 46 and 50.

[0033] Figure 3 illustrates the direction reversing mechanism in a second position. As can be shown by arrow 60, the flange 42 has been actuated so that there is an interconnection between the teeth 48 of the second bevel gear 34 and the teeth 52 of the flange 42. Accordingly, rotation of the first shaft 32 (see arrow 56) causes the rotation of the second shaft 40 in a second direction (see arrow 62), which is reversed with respect to the first rotation direction of the second shaft 40 illustrated in Figure 2.

[0034] Turning now to Figure 4 of the appended drawings, a drive assembly 100 according to a second illustrative embodiment will be described. It is to be noted that since the drive assembly 10 discussed hereinabove an illustrated in Figures 1 to 3 and the drive assembly 100 are similar, only the differences therebetween will be described herein, for concision purpose.

[0035] Generally stated, the main difference between the drive assemblies 10 and 100 concerns a mixing planetary gearset 102 provided between the CVT 12 and the direction reversing mechanism 14.

[0036] The operation of the drive assembly 100 being identical to the operation of the drive assembly 10 discussed hereinabove.

[0037] Turning now to Figure 5 of the appended drawings, a drive assembly 200 according to a third illustrative embodiment will be described. It is to be noted that since the drive assembly 10 discussed hereinabove an illustrated in Figures 1 to 3 and the drive assembly 200 are similar, only the differences therebetween will be described herein, for concision purpose.

[0038] Generally stated, the main difference between the drive assemblies 10 and 200 concerns the direction reversing mechanism 202 which has the same topology and elements as the direction reversing mechanism 14 of Figures 1 to 3 but has been connected to the CVT 12 via its second shaft 40. The first shaft 32 becoming the out put of the drive assembly.

[0039] The operation of the drive assembly 200 being identical to the operation of the drive assembly 10 discussed hereinabove.

[0040] It will be understood by one skilled in the art that even though a three-position bevel gear selection mechanism was described herein, a two- position bevel gear selection mechanism, i.e. one lacking a neutral position, could be used.

[0041] It will also be understood that while a dog clutch type assembly was described herein, other types of clutches could be used. For example, a synchronizer to ease shifting or a wet or dry clutch could be used.

[0042] The appended drawings illustrate the CVT as being a dual- cavity toroidal CVT. One skilled in the art will understand that other CVT technologies could be used in the drive assemblies described herein.

[0043] Also, while the drive assembly described hereinabove and illustrated in the appended drawings, uses an output drum 28 so that the output shaft 30 of the CVT 12 is coaxial with the input shaft thereof, other CVT configurations could be used. As a non-limiting example, gears could be meshed with the output disk to position an output shaft parallel to the input shaft.

[0044] It is to be understood that the drive assembly is not limited in its application to the details of construction and parts illustrated in the accompanying drawings and described hereinabove. The drive assembly is capable of other embodiments and of being practiced in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation. Hence, although the drive assembly has been described hereinabove by way of illustrative embodiments thereof, it can be modified, without departing from the spirit, scope and nature of the subject invention.

Claims

WHAT IS CLAIMED IS:

1 . A drive assembly comprising:

a CVT provided with a input and with an output;

a direction reversing mechanism having a first shaft and a second shaft; one of the first and second shafts being connected to the output of the CVT; the other of the first and second shaft defining the output shaft of the direction reversing mechanism; the direction reversing mechanism including:

a first bevel gear rotatably mounted to the first shaft; a second bevel gear rotatably mounted to the first shaft;

a third bevel gear meshed with both the first and second bevel gear; the third bevel gear being so mounted to the second shaft as to rotate therewith;

a bevel gear selection mechanism so mounted to the first shaft as to rotate therewith; the bevel gear selection mechanism being actuatable between a first position where the first bevel gear is so connected to the first shaft as to rotate therewith and a second position where the second bevel gear is so connected to the first shaft as to rotate therewith;

whereby, a) when the bevel gear selection mechanism is in the first position, the output shaft of the direction reversing mechanism rotates in a first direction, and b) when the bevel gear selection mechanism is in the second position, the output shaft of the direction reversing mechanism rotates in a second direction, reversed with respect to the first direction.

2. A drive assembly as recited in claim 1 , wherein the bevel gear selection mechanism is provided with a third, neutral position where neither of the first and second bevel gears is connected to the first shaft so as to rotate therewith.

3. A drive assembly as recited in claim 1 , wherein the first shaft of the direction reversing mechanism is connected to the output of the CVT and wherein the second shaft defines the output shaft of the direction reversing mechanism.

4. A drive assembly as recited in claim 1 , further comprising a mixing planetary gearset provided between the output of the CVT and the one of the first and second shafts of the direction reversing mechanism.

5. A drive assembly as recited in claim 1 , further comprising a separation wall provided between the CVT and the direction reversing mechanism; the separation wall allowing the output of the CVT therethrough.

6. A drive assembly as recited in claim 1 , wherein the direction reversing mechanism includes a dog clutch flange so mounted to the first shaft as to axially move thereon between the first and second positions while rotating therewith.

7. A drive assembly as recited in claim 6, wherein the first and second bevel gears include teeth facing the dog clutch flange and so configured as to selectively interconnect therewith.