Transmission assembly
A multi cone clutch is used on the input to a transmission. The clutch has a multi-cone structure which employs sandwiched cone friction surfaces. The multi-cone structure is used for gears selection inside the transmission. In this case, sandwiched cone friction surfaces are in free or unengaged state while the corresponding friction surfaces are engaged. The cone selector is used to engage free rotating female part of a multi-cone selector. A hydraulic actuator is received by internal gear case wall to prevent any radial or axial movement of the actuator itself. The crown of hydraulic spring outlet piston is formed so as to clip in a housing of a thrust bearing is to provide relative rotational movements between cone clutch male part and a piston in idling or power transmitting mode.
Latest SELECT DESIGN TECHNOLOGIES LIMITED Patents:
THIS INVENTION relates to a transmission assembly and in particular but not limited to a compact transmission assembly employing two shafts.
BACKGROUND OF THE INVENTIONThe applicant's U.S. Pat. No. 6,092,432 and International patent application WO 00/71909 are incorporated by reference and describe constant mesh transmissions employing hydraulic gear selectors used to engage free rotating gears on a first shaft to transmit drive to a fixed gear on an adjacent shaft. The present invention relates to the use of a multi-cone clutch suitable for the types of transmissions described and controlled in accordance with the general type arrangements disclosed in U.S. Pat. 6,092,432 and WO 00/71909.
OUTLINE OF THE INVENTIONIn one aspect the present invention resides in a multi-cone clutch in combination with a transmission, the transmission having a main input drive shaft and the multi-cone clutch being on the main drive shaft to the transmission. The expression “multi-cone” as used herein means more than two cone surfaces and specifically refers to the use of driven cone surfaces sandwiched between other cone surfaces.
Preferably, the clutch is a quad cone clutch on the input shaft and is used in place of a conventional torque convertor. Thus it maybe applied to any transmission.
Preferably, the multi-cone clutch comprises female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage and thereby couple an input drive to the drive shaft and then to the transmission.
Preferably, the male cone body drive means comprises a hydraulic drive assembly comprising an input piston, an output piston and hydraulic coupling between the input and output pistons. The hydraulic coupling is preferably configured to amplify the applied force. The hydraulic cylinder assembly of said male cone body drive means is preferably a fixed annular cylinder assembly with thrust bearings coupling the output piston to the male cone body.
Preferably, increase in surface area may be accomplished by increasing the number of driven cone surfaces between the male and female cone surfaces.
In one preferred form the male and female cone bodies are part of a quad cone structure.
Preferably, the cone bodies are constrained to move axially by respective guides. The guides are typically respective concentric axially slidable guides moving in axially extending guide ways.
In a preferred embodiment the same basic multi-cone arrangement may be also be used inside the transmission. In this case the multi-cone clutch may be used as a gear selector to select and engage gears in a constant mesh transmission.
In another aspect the invention resides in a transmission assembly having an input, an output and gears permanently in mesh for selectively coupling the input to the output in predetermined ratio of input to output according to gear selection, at least one said gears being a free rotating gear having a multi-cone gear selector comprising a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage, the input having a multi-cone clutch operable to engage the transmission.
Preferably the transmission is a constant mesh transmission which employs a mix of multi-cone selectors for all the gears in the transmission, with a higher number of cone surfaces for first and reverse gear and a lower number of cone surfaces for the other gears.
In another embodiment the transmission employs a multi-cone selector assembly on the main drive shaft to the transmission proper.
In a preferred form the transmission includes at least one other gear selector comprising a drum selector employing circumferentially spaced pads, each pad having a circumferentially extending pad surface, pad drive means driving the pads into driving engagement with a drum surface, the drum surface of a normally free rotating gear assembly, the gear assembly having a gear and being engageable when said pad surfaces engage said drum surface under the influence of said drive means, the pads being pivotal to a drum surface unengaged position about a first pivot axis and being pivotal to a drum surface engaged position about a second pivot axis spaced from the first pivot axis.
Preferably, the normally free rotating gear assembly includes a gear in permanent mesh with a fixed gear. Preferably, each pad is supported by a pad carrier having a centre of gravity spaced from the pivot axes in order to urge said pad to a drum surface unengaged position under the influence of centrifugal forces. Preferably, the pad carrier has a first end nearer the centre of gravity and a second end opposite said first end and there being biassing means biassing said second end against said drive means and holding said pads in a drum surface unengaged position until overcome by said biassing means.
The pad drive means is preferably an annular hydraulic cylinder assembly having an axially moveable input piston, a radially moveable output piston and an intermediate hydraulic coupling between the pistons. Preferably, the output piston is circumferentially movable between circumferentially spaced position under the influence of said biassing means. The hydraulic cylinder assembly of the drive means is preferably a fixed annular cylinder assembly with thrust bearings coupling the output piston to the male cone body.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings and initially to
As will be desired below in relation to preferred forms of transmissions, the operation of the clutch 105 will be explained in terms of the operation of the same arrangement within the transmission and used for selection of a gear. It will be appreciated that the same arrangement of cones and drive for the engagement and release of the cones is typical in terms of use inside and outside the transmission proper. Therefore the following description of multi-cone gear selectors applies to the multi-cone clutch on the input shaft.
Referring to
Input shaft 11A is connected to a power source and carries first gear 1 firmly fixed to it and in permanent mesh with free rotating gear (1A in
Hydraulic fluid pressure when supplied to hydraulic cylinder 23 of
In the preferred embodiment twin cone selectors are applicable to first and reverse gears as shown in
Referring to
The hydraulic spring comprises body 47, output piston 49, input piston 48 and spring sack 50. The sack 50 is made of elastic material compatible with transmission and hydraulic fluids. It is filled with fluid or gel of hydraulic properties and fully sealed making it leak-proof. The spring sack 50 is shaped to fit exactly a cavity as defined by piston 49 and 48 and spring body 47. This provides constant pressure on pads 45 from output piston 49 when spring sack 50 is pressed by piston 48 and converts axial movement to radial movement. The force produced by output piston 49 is a function of its cross section and cross sectional area of input piston 48 as well as force from push ring 51 provided by annular hydraulic cylinder 52.
Referring to
This illustrated embodiment exemplifies the use of twin cone friction selectors and drum friction selectors both fitted with hydraulic springs as devices for selecting and engaging gears.
In addition permutations of the selectors may be used depending upon design requirements, some gears may employ a greater clutching surface, for example first gear and reverse may employ extra driven cones than the other gears. This is illustrated in the comparison drawing of
Accordingly, it will be appreciated that many modifications and improvements can be made to the transmission general arrangement system and gear selectors as exemplified above without departing from the broad ambit and scope of the invention as set out in the appended claims.
Claims
1. A multi-cone clutch in combination with a transmission, the transmission having a main input drive shaft and the multi-cone clutch being on the main drive shaft to the transmission.
2. A multi-cone clutch in combination with a transmission according to claim 1 wherein the clutch is a quad cone clutch on the input shaft and is used in place of a conventional torque convertor.
3. A multi-cone clutch in combination with a transmission according to claim 1 wherein the multi-cone clutch comprises a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage and thereby couple an input drive to the drive shaft and then to the transmission.
4. A multi-cone clutch in combination with a transmission according to claim 1 wherein the multi-cone clutch comprises a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage, the male cone body drive means comprises a hydraulic drive assembly comprising an input piston, an output piston and hydraulic coupling between the input and output pistons.
5. A multi-cone clutch in combination with a transmission according to claim 1 wherein the multi-cone clutch comprises a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage, the male cone body drive means comprises a hydraulic drive assembly comprising an input piston, an output piston and hydraulic coupling between the input and output pistons, the hydraulic coupling being configured to amplify the applied force.
6. A multi-cone clutch in combination with a transmission according to claim 1 wherein the multi-cone clutch comprises a female cone surface and a male cone body having a driven cone surface and a driving cone surface, the driven cone surface being located between the driving cone surface and the female cone surface, the male cone body being axially moveable by a male cone body drive means to cause said cone surfaces to engage, the male cone body drive means comprises a hydraulic drive assembly comprising an input piston, an output piston and hydraulic coupling between the input and output pistons, the hydraulic cylinder assembly of said male cone body drive means being a fixed annular cylinder assembly with thrust bearings coupling the output piston to the male cone body.
7. A multi-cone clutch in combination with a transmission according to claim 1 wherein cones are constrained to move axially by respective guides.
8. A multi-cone clutch in combination with a transmission according to claim 1 wherein cones are constrained to move axially by respective guides, the guides being respective concentric axially slidable guides moving in axially extending guide ways.
Type: Application
Filed: Apr 30, 2007
Publication Date: Aug 30, 2007
Applicant: SELECT DESIGN TECHNOLOGIES LIMITED (Victoria)
Inventor: Boris Klaricic (Victoria)
Application Number: 11/790,969
International Classification: F16D 21/04 (20060101);