AU7256800A

AU7256800A - System in manual transmission for reducing required manual force during N-R shifting

Info

Publication number: AU7256800A
Application number: AU72568/00A
Authority: AU
Original assignee: Hyundai Motor Co
Current assignee: Hyundai Motor Co
Priority date: 2000-05-12
Filing date: 2000-12-29
Publication date: 2001-11-15
Also published as: KR20010104002A; JP2001324011A; CN1323959A; DE10065740A1; KR100380053B1

Description

Our Ref:7566400 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Address for Service: Invention Title: Hyundai Motor Company 140-2, Kye-dong Jongro-ku Seoul Republic of Korea (South) DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 System in manual transmission for reducing required manual force during N-R shifting The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 00-12-27; 4:05PM; i ,1 3/ SYSTEM IN MANUAL TRANSMISSION FOR REDUCING REQUIRED MANUAL FORCE DURING N-R SHIFTING BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a system in a manual transmission for reducing the manual force required durng N-R shifting. More particularly, the present invention relates to a system for a manual transmission that artificially applies a drag torque to an input shaft before N-R shifting is started such that an RPM difference needed to synchronize a synchronizer ring is reduced, thereby enabling N-R shifting with a minimal amount of force.

Description of the Related Art A synchronizer in a manual transmission is either of a type that does or does not utilize a constant-mesh application to a reverse shaft. In the case Swhere constant-mesh is not applied to the reverse shaft, the synchronizer is .15 categorized as a single-cone synchronizer. When performing N-R shifting, with reference to FIG. 4, if a synchronizer sleeve 51 moves in an axial direction S to synchronize an input shaft 50, a constant torque T is generated at a synchronizer ring 53 in a rotational direction to obstruct the movement of the S:synchronizer sleeve 51. Accordingly, a large synchronization force is needed by the synchronizer sleeve 51.

In order to generate the needed force in conventional manual transmissions, a double or triple cone is used, a diameter of the ring is

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00-12-27; 4:05PM; 4/ increased, or a cone angle is decreased to enhance a synchronization capacity.

However, for N-R shifting, problems arise in the reverse layout, it is difficult to increase synchronization capacity for N-R shifting, and noise and other difficulties are encountered.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems.

It is an object of the present invention to provide a system for a manual transmission that artificially applies a drag torque to an input shaft as N-R shifting is started such that an RPM difference needed to synchronize a synchronizer ring is reduced, thereby enabling N-R shifting with a minimal .:amount of force.

To achieve the above object, the present invention provides a system in a manual transmission for reducing the manual force required during N-R 15 shifting comprising drag torque generating means for creating a drag torque at an input shaft during N-R shifting; and a N-R shift detection switch for applying an electrical signal to the drag torque generating means prior to the start of N-R shifting.

According to a feature of the present invention, the drag torque generating means comprises a friction element provided opposing a circumference of the input shaft to engage with the input shaft, thereby generating friction between the friction element and the input shaft; and an 00-12-27; 4:05PM; 5/ actuator for controlling the movement of the friction element toward and away from the input shaft according to the electrical signals applied by the N-R shift detection switch.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention: FIG. 1 is partial sectional view of a reverse gear in a state prior to the operation of a system in a manual transmission for reducing the required manual force during N-R shifting according to a preferred embodiment of the present invention; FIG. 2 is a partial sectional view of a reverse gear in a state during the operation of a system in a manual transmission for reducing the required manual force during N-R shifting according to a preferred embodiment of the 15 present invention; FIG. 3 is a partial sectional view of a reverse gear in a state following the operation of a system in a manual transmission for reducing the required manual force during N-R shifting according to a preferred embodiment of the :present invention; and FIG. 4 is a schematic drawing used to describe operations during N-R shifting performed by a conventional synchronizer for manual transmissions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 00-12-27; 4:05PM; 6/ Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIGs. 1, 2, and 3 show partial sectional views of a reverse gear in states respectively prior to, during, and following the operation of a system in a manual transmission for reducing the required manual force during N-R shifting according to a preferred embodiment of the present invention.

The system of the present invention for reducing the manual force required during N-R shifting in a manual transmission includes a drag torque generator 3 for creating a drag torque at an input shaft 1 during N-R shifting, to and a N-R shift detection switch 5 for applying an electrical signal to the drag torque generator 3 prior to the start of N-R shifting. The drag torque generator 3 includes a friction element 7 provided opposing a circumference of the input shaft 1 of the manual transmission, and an actuator 9 for controlling the movement of the friction element 7 toward and away from the input shaft 1 according to the electrical signals applied by the N-R shift detection switch The present invention is not limited to a single drag torque generator 3. That is, one or more drag torque generators 3 can be provided on the input shaft 1 depending on the design limitations of the particular vehicle.

The friction element 7 and an actuator 9 of the drag torque generator 3 are mounted to a transmission housing 11. The N-R shift detection switch 5 is provided in a shift lever unit (not shown) and acts to supply a power of a battery to the actuator 9 when operated by a shift lever 13 immediately before N-R shifting is completed.

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00-12.-27; 4:05PM; 9 7/ The operation of the system of the present invention described above and the operation of a synchronizer of a reverse gear 17 will now be described.

With reference to FIG. 1, when the shift lever 13 is in a neutral N state, power is cut off from the actuator 9 since the N-R shift detection switch 5 is not operated. As a result, the friction element 7 is not engaged with the input shaft 1. At this time, a synchronizer sleeve 19, which is provided on a synchronizer 21, is positioned so that a rotational force of the input shaft 1 is not transmitted to the reverse gear 17.

In the process of changing the position of the shift lever 13 from the above neutral N state to a reverse R state as shown in FIG. 2, the synchronizer sleeve 19 moves on the synchronizer 21 in the direction of the input shaft 1 until contacting a synchronizer ring 25. Ball bearings 23 are provided in the synchronizer 21 to aid the movement of the synchronizer sleeve 19 on the synchronizer 21. The synchronizer 21 itself also moves slightly in the direction of the synchronizer ring 25. At the same time, the shift lever 13 operates the N- R shift detection switch 5 such that the power of the battery 15 is supplied to the actuator 9. As a result, the actuator 9 engages the friction element 7 with the input shaft 1 such that a drag torque is provided to the input shaft 1.

The synchronizer 21 moves until contacting the synchronizer ring 20 such that rotational speeds of these two elements are synchronized. At the same time, the contact of the friction element 7 with the input shaft 1 reduces the rotational speed of the input shaft 1. Accordingly, an RPM difference needed to synchronize the synchronizer ring 25 is reduced. That is, since the 00-12-27; 4:05PM; 8/ drag torque generated on the input shaft 1 by the friction element 7 reduces an RPM of the input shaft 1 as shifting is started, so the synchronizing force that needs to be exerted by the synchronizer ring 25 is substantially reduced. Hence, a minimal influence of constant torque is given to the synchronizer sleeve 19 as it approaches and reaches a position of contacting and meshing with the synchronizer ring 25, thereby minimizing the force needed to move the synchronizer sleeve 19.

Next, with reference to FIG. 3, when the shift lever 13 is positioned fully in the reverse R range from the neutral N range, the N-R shift detection switch 5 is disengaged such that the power supplied to the actuator is cut off.

Accordingly, the friction element 7 moves away from the input shaft 1. At this *0 time, the synchronizer sleeve 19 is meshed with the synchronizer ring 25 and a clutch gear 27 such that the rotational force of the input shaft 1 is transmitted to the reverse gear 17.

In the system for a manual transmission of the present invention described above, a drag torque is applied to an input shaft before N-R shifting o is started such that an RPM difference needed to synchronize a synchronizer *o ring is reduced, thereby enabling N-R shifting with a minimal amount of force.

Also, an overall shift feel is improved. Finally, the present invention enables a 20 reduction in the size of the reverse synchronizer ring.

Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concepts herein taught 00-1.2-27; 4:05PN; 9/ which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as defined in the appended claims.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general acknowledge in Australia.

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Claims

1. A system in a manual transmission for reducing the manual force required during N-R shifting, comprising: drag torque generating means for creating a drag torque at an input shaft during N-R shifting; and a N-R shift detection switch for applying an electrical signal to the drag torque generating means at the start of N-R shifting.

2. The system of claim 1 wherein the drag torque generating means comprises: a friction element provided opposing a circumference of the input shaft to engage with the input shaft, thereby generating friction between the friction element and the input shaft; and an actuator for controlling the movement of the friction element toward and away from the input shaft according to the electrical signals applied by the N-R shift detection switch. O 0

3. A system for reducing the manual force required during N-R shifting in a manual transmission substantially as hereinbefore described with reference to the drawings. DATED this 2 9 th day of December 2000 HYUNDAI MOTOR COMPANY By Its Patent Attorneys DAVIES COLLISON CAVE