SE540538C2 - A latch cone ring and an intermediate cone ring for a synchronizing arrangement, a synchronizing arrangement, a gearbox and a vehicle - Google Patents

Abstract

The invention relates to a latch cone ring for a synchronizing arrangement (12), comprising a substantially circular friction surface (28) with a central axis, and at least one latch tooth (36) arranged on a periphery (39) of the latch cone ring (14). At least one driver means (96) is arranged on the latch cone ring (14), and at least one engagement means (104, 106) is arranged on the at least one driver means (96). The invention also relates to an intermediate cone ring for a synchronizing arrangement (12), comprising a substantially circular friction surface (28) with a central axis. At least one driving slot (98) is arranged on the intermediate cone ring (92), and at least one engagement means (104, 106) is arranged on the at least one driving slot (98). The invention also relates to a synchronizing arrangement (12) comprising such a latch cone ring (14) and an intermediate cone ring (92), a gearbox (4) comprising such a synchronizing arrangement (12) and a vehicle (1) comprising such a gearbox (4).

Description

A latch cone ring and an intermediate cone ring for a synchronizing arrangement, a synchronizing arrangement, a gearbox and a vehicle BACKGROUND AND PRIOR ART The invention relates to a latch cone ring for a synchronizing arrangement according to the preamble of patent claim 1. The invention relates to an intermediate cone ring for a synchronizing arrangement according to the preamble of patent claim 11 . The invention also relates to a synchronizing arrangement comprising such a latch cone ring and intermediate cone ring according to the preamble of patent claim 15. The invention also relates to a gearbox comprising such a synchronizing arrangement according to the preamble of patent claim 17. The invention also relates to a vehicle comprising such a gearbox according to the preamble of patent claim 18.

When shifting gears in a gearbox, cogwheels are engaged and locked on shafts by means of axially displaceable sleeves. However, the sleeve, cogwheel and shaft may have different speeds when a gear should be shifted and the cogwheel should be locked on the shaft by means of the sleeve. Therefore, a synchronizing arrangement is used to synchronize the speed between the sleeve, cogwheel and shaft before the cogwheel is locked on the shaft. The synchronizing arrangement comprises a latch cone ring and an inner cone ring arranged on the side of the cogwheel. The gearbox may comprise a split gearbox, a main gearbox and a range gearbox which all need one or several synchronizing arrangements for completing a synchronous gear shifting.

In order to obtain good synchronization in the gearbox, the surface of peripheral latch teeth on the latch cone ring, which face the sleeve and are designed to engage internal teeth in the sleeve during synchronization, must be angled relative to the axis of rotation of the latch cone ring, said angle being balanced against the braking torque that the latch cone ring transmits to the sleeve in or der to achieve synchronous speed. This means that said angle must be designed so that the latch teeth on the latch cone ring engage with that portion of the internal teeth in the sleeve that are at said angle and act on the sleeve sufficiently to achieve synchronous speed and then disengage from the portion of the internal teeth in the sleeve at said angle when the sleeve is to engage with the inner cone ring when synchronous speed has been obtained. In the engaged position between the sleeve and the inner cone ring, the internal teeth in the sleeve engage with peripheral coupling teeth of inner cone ring. The inner cone ring is attached to the cogwheel. To ensure that synchronous speed is reached before the sleeve passes the latch cone ring axially, the teeth of the latch cone ring must disengage from internal teeth at the right moment. This is achieved by a torque balance where the friction torque, also defined as the synchronizing torque, seeks to increase the overlap between the latch cone teeth and the inner cone teeth, while the torque arising from the teeth-teeth contact seeks to reduce the overlap between the teeth. When the peripheral latch teeth on the latch cone ring have disengaged from the internal teeth in the sleeve when synchronous speed has been obtained between the sleeve and the inner cone ring, the sleeve will be axially displaced so that the latch cone ring is moved inwards into the sleeve and stops in an axial position relative to the sleeve, said axial position being determined by the position at which the sleeve meets and engages with the inner cone ring on the cogwheel.

A number of spring-loaded balls are arranged in the sleeve, the purpose of these is to ensure that pre-synchronization occurs. The spring-loaded balls act on a number of abutment means arranged on the latch cone ring to ensure that the latch teeth of the latch cone ring are in the correct axial position relative to the internal teeth of the sleeve during pre-synchronization. During presynchronization, the oil present between the conical surfaces must be evacuated so that a sufficiently high friction torque is developed, effectively blocking gear engagement during asynchronous speed. The spring-loaded balls prevents gear engagement before the latch cone can block gear engagement.

When the pre-synchronization has ended and the synchronization or main synchronization should start the spring-loaded balls will be pressed radially outwards so that the sleeve is allowed to move axially in relation to the latch cone ring.

During the pre-synchronization and the following synchronization process the axial position of the latch cone ring is defined because of the axial force from the sleeve acting on the latch cone ring. After the synchronization process and the gear shifting operation the sleeve is coupled to the inner cone ring and also the cogwheel. In this position the sleeve, the latch cone ring, the inner cone ring and the cogwheel rotate together with the shaft as one unit. However, after a gear shifting operation when the cogwheel is released from the shaft, the sleeve is returned to an initial position in which no axial force acting on the latch cone ring. As a result, the axial position of the latch cone ring will not be defined when no axial force is acting on the latch cone ring and the sleeve is in its initial position. Also, because there is a distance between the inner cone ring and the sleeve, which distance is larger than the axial extension of the latch cone ring, when the sleeve is in the initial position, the latch cone ring is allowed to move axially in the space between the sleeve and the inner cone ring. Thus, the latch cone ring may come into contact with the inner cone ring. Because the latch cone ring rotates when the sleeve and the shaft rotate, and the inner cone ring connected to the cogwheel rotates with another speed, a relative movement will arise between the latch cone ring and the inner cone ring. This contact and relative movement leads to losses in the gearbox, which may increase the fuel consumption in the vehicle. Also, the relative movement between the latch cone ring and the inner cone ring may lead to wear of the friction surfaces of the latch cone ring and the inner cone ring. Also, the undefined position of the latch cone ring may lead to noise due to vibrations in the latch cone ring and due to the contact between the latch cone ring and the inner cone ring.

The synchronizing arrangement may be provided with more than two cone rings. Such a synchronizing arrangement may generate a large amount of torque. In addition to the latch cone ring and the inner cone ring the synchronizing arrangement may be provided with a number of intermediate cone rings, which have a substantially circular body and is provided with substantially circular friction surfaces, which have a frusto conical shape. The cone rings may be connected to each others in pairs, so that when an axial force from the sleeve acts on the latch cone ring the friction surfaces on the latch cone ring and one of the intermediate cone rings will engage the friction surfaces on the inner cone ring and the other intermediate cone ring. However, after a gear shifting operation, when the cogwheel is released from the shaft, the sleeve is returned to an initial position in which no axial force acting on the latch cone ring. As a result, the axial position of the latch cone ring and also the axial position of the intermediate cone rings will not be defined when no axial force is acting on the latch cone ring and the sleeve is in its initial position. Thus, this may lead to losses in the gearbox, an increase in the fuel consumption in the vehicle, wear of the friction surfaces of the cone rings and to noise due to vibrations in the cone rings and due to the contact between the cone rings, as described above.

The document US5105927A discloses a synchronizing means for a gearbox provided with an annular spring instead of spring-loaded balls.

The document EP2677189A1 discloses a gearbox for vehicles, comprising a planetary gear set with an axially displaceable internal ring gear forming a part of a synchronizing means. Locking rings are arranged in internal grooves in the internal ring gear. The gearbox also comprises synchronizer rings which are provided with circumferential external grooves intended for the locking rings. However, the locking rings are intended to be arranged into the external grooves of the synchronizer rings when the synchronizing means is in an active, locked position. In a rest position of the synchronizing means the locking rings are arranged in the internal grooves in the internal ring gear.

The document EP2060815A1 discloses a torque transmission device with cone rings and an idle pinion using driving dogs. The cone rings are set in contact by a control force exerted by a sleeve to transmit a torque to the pinion. Surfaces of the driving dogs are in contact with surfaces of cavities during the torque transmission.

SUMMARY OF THE INVENTION Despite prior art, there is a need to develop a latch cone ring for a synchronizing arrangement, which reduces losses in a gearbox, reduces fuel consumption of a vehicle in which the gearbox is arranged, which reduces wear of the latch cone ring and which reduces noise due to vibrations in the latch cone ring. There is also a need to develop a latch cone ring which reduces wear of an intermediate cone ring and which reduces noise due to vibrations in the intermediate cone ring.

The object of the invention is thus to provide a latch cone ring of the type defined in the introduction, which reduces losses in a gearbox, reduces fuel consumption of a vehicle in which the gearbox is arranged, which reduces wear of the latch cone ring, which reduces noise due to vibrations in the latch cone ring and which also reduces wear of an intermediate cone ring and which reduces noise due to vibrations in the intermediate cone ring.

These objectives are achieved with a latch cone ring for a synchronizing arrangement, which is characterized by the features specified in patent claim 1.

There is also a need to develop an intermediate cone ring for a synchronizing arrangement, which reduces losses in a gearbox, reduces fuel consumption of a vehicle in which the gearbox is arranged, which reduces wear of the intermediate cone ring and which reduces noise due to vibrations in the intermediate cone ring.

The object of the invention is thus to provide an intermediate cone ring of the type defined in the introduction, which reduces losses in a gearbox, reduces fuel consumption of a vehicle in which the gearbox is arranged, which reduces wear of the intermediate cone ring and which reduces noise due to vibrations in the intermediate cone ring.

These objectives are achieved with an intermediate cone ring for a synchronizing arrangement, which is characterized by the features specified in patent claim 11.

These objectives are also achieved with a synchronizing arrangement, which is characterized by the features specified in patent claim 15.

These objectives are also achieved with a gearbox, which is characterized by the features specified in patent claim 17.

These objectives are also achieved with a vehicle, which is characterized by the features specified in patent claim 18.

According to the invention, an advantageously latch cone ring for a synchronizing arrangement is achieved, which reduces losses in a gearbox. Since the friction surface of the latch cone ring is prevented from coming into contact with friction surfaces of the other cone rings no friction losses arise between the latch cone ring and the other cone rings. As a result the fuel consumption will not increase. Also, any wear of the friction surfaces of the latch cone ring and the other cone rings will be reduced since the friction surfaces should have no contact when no synchronization occurs. When the position of the latch cone ring is defined vibrations in the latch cone ring are prevented and therefore no noise is created due to vibrations in the latch cone ring.

The engagement means arranged on the driver means may interact with a cone ring in the synchronizing arrangement and prohibit the cone ring to move in an axial direction, so that the axial position of the cone ring is defined. As a result, friction surfaces of the cone rings are prevented from coming into contact with each others.

According to an embodiment of the invention at least one abutment means and a circumferential groove are so configured that one first point on the first surface of the at least one abutment means and one second point in the circumferential groove are situated on a periphery of a common sphere with a radius. With such a configuration of the circumferential groove and the abutment means the latch cone ring can be locked in a fixed axially position in relation to a sleeve and the inner ring in the synchronizing arrangement. For example spring-loaded balls arranged in the sleeve may be used having dimensions substantially corresponding to the common sphere. The spring-loaded balls interact with the circumferential groove and the abutment means so that the first point on the first surface of the at least one abutment means and the second point in the circumferential groove are situated on a periphery of the springloaded ball. As a result, the axial position of the latch cone ring will be defined when the sleeve is in its initial position in the synchronizing arrangement. Such initial position of the sleeve may correspond to a natural position of the gear. Also, the latch cone ring is prevented from moving axially in the space between the sleeve and the inner cone ring, and therefore the latch cone ring cannot come into contact with the inner cone ring. Thus, an increase in fuel consumption, wear of the friction surfaces of the latch cone ring and the inner cone ring and noise due to vibrations in the latch cone ring are prevented.

According to another embodiment of the invention the circumferential groove in a sectional view is provided with a first radius arranged in a first portion of the circumferential groove and a second radius arranged in a second portion of the circumferential groove. Such a configuration of the circumferential groove ensures that the second point in the circumferential groove will be clearly defined so that the latch cone ring can be locked in a fixed axially position in relation to the sleeve and the inner ring in the synchronizing arrangement.

According to still another embodiment of the invention the first radius is smaller than the second radius. Such a configuration of the circumferential groove ensures that the second point in the circumferential groove will be clearly defined so that the latch cone ring can be locked in a fixed axially position in relation to the sleeve and the inner ring in the synchronizing arrangement.

According to still another embodiment of the invention the first portion is arranged closer to the abutment means than the second portion. Such a configuration of the circumferential groove ensures that the second point in the circumferential groove will be clearly defined so that the latch cone ring can be locked in a fixed axially position in relation to the sleeve and the inner ring in the synchronizing arrangement. When for example spring-loaded balls arranged in the sleeve are used with dimensions substantially corresponding to the common sphere, the configuration of the circumferential groove together with the abutment means will lock the latch cone ring in an axial position.

According to still another embodiment of the invention the second point is situated in the second portion. Such a configuration of the circumferential groove ensures that the second point in the circumferential groove will be clearly defined so that the latch cone ring can be locked in a fixed axially position in relation to the sleeve and the inner ring in the synchronizing arrangement.

Also, according to the invention, an advantageously intermediate cone ring for a synchronizing arrangement is achieved, which reduces losses in a gearbox. Since the friction surface of the intermediate cone ring is prevented from coming into contact with friction surfaces of the other cone rings in the synchronizing arrangement no friction losses arise between the intermediate cone ring and the other cone rings. As a result the fuel consumption will not increase. Also, any wear of the friction surfaces of the intermediate cone ring and the other cone rings will be reduced since the friction surfaces have no contact during the relative movement. When the position of the intermediate cone ring is defined vibrations in the intermediate cone ring are prevented and therefore no noise is created due to vibrations in the intermediate cone ring.

The engagement means arranged on the driving slot may interact with a cone ring in the synchronizing arrangement and prohibit the cone ring to move in an axial direction, so that the axial position of the cone ring is defined. As a result, friction surfaces of the cone rings are prevented from coming into contact with each others.

BRIEF DESCRIPTION OF THE DRAWINGS Below is a description of, as examples, preferred embodiments of the invention with reference to the enclosed drawings, in which: Fig. 1 shows schematically a vehicle in a side view, with a synchronizing arrangement according to the invention, Fig. 2 shows a view in perspective of a segment of a latch cone ring for a synchronizing arrangement according to a first embodiment of the invention, Fig. 3 shows a sectional view of a synchronizing arrangement according to the invention, Fig. 4 shows a sectional view along line I - I of the latch cone ring according to the invention, Fig. 5 shows a sectional view of a synchronizing arrangement according to the invention in a pre-synchronizing position, Fig. 6 shows a sectional view of a synchronizing arrangement according to the invention in a synchronizing position, Fig. 7 shows a sectional view of a synchronizing arrangement according to the invention in a position when the synchronizing process has ended, Fig. 8 shows a view in detail from above of a latch cone ring according to the first embodiment of the invention, Fig. 9 shows a sectional view along line II - II in fig. 8, Fig. 10 shows a sectional view in detail along line II - II in fig. 8, Fig. 11 shows a side view of a synchronizing arrangement provided with three cone rings according to the invention, Fig. 12 shows a front view of a segment of a synchronizing arrangement provided with four cone rings according to the invention, Fig. 13 shows a sectional view along line III - III in fig. 12, and Fig. 14 shows a sectional view along line IV - IV in fig. 12.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE IN-VENTION Fig. 1 shows a side view of a vehicle 1, e.g. a truck, which comprises an engine 2 and a gearbox 4 provided with a synchronizing arrangement 12 according to the invention. The engine 2 is connected to the gearbox 4 and the gearbox 4 is further connected to driving wheels 8 of the vehicle 1 via a propeller shaft 10. Preferably, the engine 2 is an internal combustion engine but another type of engine 2 is also applicable, such as an electrical engine. The gearbox 4 may be a manual transmission or an automated manual transmission.

Fig. 2 shows view in perspective of a segment of a latch cone ring 14 for the synchronizing arrangement 12 according to the invention. The latch cone ring 14 comprises at least one latch tooth 36 arranged on a periphery 39 of the latch cone ring 14 and preferably also at least one abutment means 42 is arranged on the periphery 39 of the latch cone ring 14. The abutment means 42 is provided with a first inclined surface 70.

Fig. 3 shows a sectional view of the synchronizing arrangement 12 according to the invention. The synchronizing arrangement 12 comprises the latch cone ring 14, an inner cone ring 16 arranged on the side of a cogwheel 18 and a sleeve 20, which is axially displaceable by means of a shifter fork 22. The shifter fork 22 is axially displaceable by means of an actuating means 24. The latch cone ring 14 and the inner cone ring 16 are provided with interacting friction surfaces 28, which preferably are of a conical design. The shifter fork 22 transmit axial force from the sleeve 20 to the latch cone ring 14 in order to bring about contact between the friction surfaces 28 on the latch cone ring 14 and the inner cone ring 16 during gear shifting. This means that an oil film formed between the friction surfaces 28 is displaced and an initial torque between latch cone ring 14 and the inner cone ring 16 builds up.

When shifting gears in a gearbox 4 the cogwheel 18 is engaged and locked on a shaft 30 by means of the axially displaceable sleeve 20. A hub 32 provided with splines 34 on the periphery is attached to the shaft 30 and allows the sleeve 20 to move axially. The hub 32 transmits torque between the shaft 30 and the sleeve 20. Flowever, the sleeve 20, cogwheel 18 and shaft 30 may have different speeds when the gear should be shifted and when the cogwheel 18 should be locked on the shaft 30 by means of the sleeve 20. The synchronizing arrangement 12 is therefore used to synchronize the speed between the sleeve 20, cogwheel 18 and shaft 30 before the cogwheel 18 is locked on the shaft 30.

The shifter fork 22 transmits axial force from the sleeve 20 to the latch cone ring 14 in order to bring about contact between the friction surfaces 28 on the latch cone ring 14 and the inner cone ring 16 during gear shifting. This means that an oil film formed between the friction surfaces 28 is displaced and an initial torque between latch cone ring 14 and the inner cone ring 16 builds up.

In order to obtain good synchronization in the gearbox 4, the surface of the latch teeth 36 on the latch cone ring 14, which face the sleeve 20 and are designed to engage internal teeth 38 in the sleeve 20 during synchronization, must be angled relative to the axis of rotation of the latch cone ring 14, said angle being balanced against the braking torque that the latch cone ring 14 transmits to the sleeve 20 in order to achieve synchronous speed.

A number of balls 40, each loaded with a spring 41, are arranged in the sleeve 20, the purpose of these is to ensure that pre-synchronization occurs. The spring-loaded balls 40 act on the abutment means 42 arranged on the latch cone ring 14 to ensure that the latch teeth 36 of the latch cone ring 14 are in the correct axial position relative to the internal teeth 38 of the sleeve 20 during pre-synchronization and the abutment means 42 press the spring-loaded balls 40 radially outwards when the sleeve 20 moves axially in relation to the latch cone ring 14 when the pre-synchronization has ended and when the synchronization or main synchronization should start. In fig. 3 the sleeve 20, latch cone ring 14 and the inner cone ring 16 are depicted on a distance to each other for clarity reason. In fig. 3 the cogwheel 18, shaft 30 and hub 32 are schematically disclosed. The latch teeth 36 extend in a direction parallel to the centre line of the latch cone ring 14 and in a peripheral direction. The abutment means 42 have a larger extension than the latch teeth 36 in the direction parallel to the centre line 44. A circumferential groove 49 is arranged in the peripheral surface of the latch cone ring 14 adjacent to the abutment means 42. Preferably, the circumferential groove 49 extends completely around the peripheral surface of the latch cone ring 14. However, a number of shorter circumferential grooves 49 may as an alternative extend as indentations on the the peripheral surface of the latch cone ring 14.

Instead of spring-loaded balls 40, it is possible to use another locking devices such as an annular curved wire (not disclosed), appropriately with a circular cross section, which is resiliently fixed in the groove 49 and thus has a predetermined gap between its opposite ends. This gap allows a certain radial compression of the wire.

Fig. 4 shows a sectional view along line I - I of the latch cone ring 14 according to the invention. In the disclosed embodiment four abutment means 42 are arranged on a substantially equally distance on the periphery 39 of the latch cone ring 14. Also, the latch teeth 36 are arranged on a substantially equally distance on the periphery 39 of the latch cone ring 14.

Fig. 5 shows a sectional view of a synchronizing arrangement 12 according to the invention in a pre-synchronizing position. When shifting gear in the gearbox 4 the shifter fork 22 acts with an axial force on the sleeve 20 and displaces the sleeve 20 and also the latch cone ring 14 axially in relation to the hub 32 in direction towards the inner cone ring 16. The spring-loaded balls 40 are pressed into the direction of the circumferential groove 49 so that the axially position of the latch cone ring 14 in relation to the sleeve 20 will be defined. For this reason the groove 49 has a design which interacting with the springloaded ball 40. As mentioned above, the spring-loaded balls 40 also act on the abutment means 42 arranged on the latch cone ring 14, so that the latch cone ring 14 will be displaced axially by the force from the spring-loaded balls 40 when the sleeve 20 is displaced by means of the shifter fork 22. As the sleeve 20 and the latch cone ring 14 are displaced axially the friction surfaces 28 on the latch cone ring 14 and the inner cone ring 16 will be brought to an adjacent position to each other. However, as the gearbox 4 is filled with oil a thin film 29 of oil is created between the friction surfaces 28 on the latch cone ring 14 and the inner cone ring 16. The axial force from the latch cone ring 14 acting on the inner cone ring 16 means result in that the oil film formed between the friction surfaces 28 is displaced. The interacting surfaces of the latch teeth 36 of the latch cone ring 14 and the internal teeth 38 of the sleeve 20 will, after the presynchronization, meet and abut against each other during the synchronization.

The latch teeth 36 and the abutment means 42 are preferably situated at the side of each latch cone ring 14 that is closest to the inner cone ring 16 to allow the movement of the latch cone ring 14 in the sleeve 20 during the synchronization process. The abutment means 42 has a smaller radial extension than that of distance between the internal teeth 38 in the sleeve 20. This allows the movement of the latch cone ring 14 in the sleeve 20 during the synchronization process.

Fig. 6 shows a sectional view of a synchronizing arrangement 12 according to the invention in a synchronizing position in which the oil film formed between the friction surfaces 28 has been displaced during pre-synchronization, the friction surfaces 28 have contact with each other and an initial torque between latch cone ring 14 and the inner cone ring 16 is building up. The latch teeth 36 on the latch cone ring 14 engage with and rest against internal teeth 38 in the sleeve 20 during synchronization. Therefore, the surface of the latch teeth 36 on the latch cone ring 14 which engage with and rest against the surface of the internal teeth 38 in the sleeve 20 must be angled relative to the axis of rotation of the latch cone ring 14, and said angle must balance against the braking torque that the latch cone ring 14 transmits to the sleeve 20 in order to achieve synchronous speed. During the synchronization the sleeve 20, cogwheel 18 and shaft 30 have different speeds. However, when a synchronous speed has been reached between the sleeve 20, cogwheel 18 and shaft 30 the angled surface of the latch teeth 36 on the latch cone ring 14 disengage from the angled surface of the internal teeth 38 in the sleeve 20, so that the sleeve 20 passes the latch cone ring 14 axially. To ensure that synchronous speed is reached before the sleeve 20 passes the latch cone ring 14 axially, the teeth 36 of the latch cone ring 14 must disengage from internal teeth 38 at the right moment. This is achieved by a torque balance where the friction torque, also defined as the synchronizing torque, seeks to increase the overlap between the latch cone teeth 36 and the inner cone teeth, while the torque arising from the teeth-teeth contact seeks to reduce the overlap between the teeth. When the sleeve 20 moves axially in relation to the latch cone ring 14, the springloaded balls 40 are pushed radially outwards due to a radially directed force from the first surface 70 on the abutment means 42. Since the first surface 70 on the abutment means 42 is inclined the spring-loaded balls 40 are gradually pushed radially outwards when the sleeve 20 moves in the axially direction.

Fig. 7 shows a sectional view of a synchronizing arrangement 12 according to the invention in a position when the synchronizing process has ended and when the peripheral latch teeth 36 on the latch cone ring 14 have disengaged from the internal teeth 38 in the sleeve 20 when synchronous speed has been obtained between the sleeve 20 and the inner cone ring 16. The internal teeth 38 on the sleeve 20 engage with external teeth 75 on the inner cone ring 16. In this position the sleeve 20 has been axially displaced so that the latch cone ring 14 has been moved inwards into the sleeve 20 and stopped in an axial position relative to the sleeve 20, said axial position being determined by the position at which the sleeve 20 meets and engages with the inner cone ring 16 on the cogwheel 18. In this position the gear shifting operation has ended and the cogwheel 18 is engaged on the shaft 30. Also, in this position the springloaded balls 40 has been pushed even more radially outwards and rest on an outer surface of the abutment means 42, depicted as a forth surface 76 of the abutment means 42.

Fig. 8 and fig. 9 show a view from above of one of the abutment means 42 on the latch cone ring 14 and a sectional view along line II - II of the abutment means 42 on the latch cone ring 14, respective. The circumferential groove 49 is arranged in the peripheral surface of the latch cone ring 14 adjacent to the first surface of the abutment means 42. A latch tooth 36 is arranged at a distance from the abutment means 42 on the peripheral surface of the latch cone ring 14. The first surface 70 is substantially flat and a normal 78 of the first surface has a first angle a in relation to a centre line 44 of the latch cone ring 14. The first angle a is 10 ° - 80 °, preferably 30 ° - 60 °, and most preferably 40 ° -50°. From fig. 8 it is evident that the abutment means 42 has a larger extension than the latch tooth 36 both in the direction parallel to the centre line 44 and in the peripheral direction. The abutment means 42 comprises a second surface 72 and a third surface 74 arranged adjacent to the first surface 70 and which extend substantially parallel to the centre line 44, both having a normal substantially orthogonal to the centre line 44. The abutment means 42 also comprises the forth surface 76 arranged adjacent to the first, second and third surfaces 70, 72, 74, which extends substantially parallel to the centre line 44, and having a normal, which intersects the centre line 44 and is substantially orthogonal to the centre line 44.

In fig. 9 also the inner cone ring 16 is shown, on which the conical surface 28 is arranged to contact the frictional surface 28 of the latch cone ring 14 during synchronization.

The circumferential groove 49 arranged in the peripheral surface of the latch cone ring 14 is together with the abutment means 42 so configured that one first point P1 on the first surface 70 of the abutment means 42 and one second point P2 in the circumferential groove 49 are situated on a periphery of a common sphere 80.

Fig. 10 shows a sectional view in detail along line II - II in fig. 8. The circumferential groove 49 and the abutment means 42 are so configured that when the common sphere 80 with a radius 82 lies on the first surface 70 of the abutment means 42 and at the same time lies in the circumferential groove 49 the periphery of the common sphere 80 will contact the first surface 70 of the abutment means 42 in only the one first point P1 and at the same time contact the surface of the circumferential groove 49 in only the one second point P2. Preferably, the circumferential groove 49 has a configuration which in the sectional view has two different radii 84, 86. One first radius 84 arranged in a first portion 88 of the circumferential groove 49, and one second radius 86 arranged in a second portion 90 of the circumferential groove 49. The first radius 84 is preferably smaller than the second radius 86. The first portion 88 of the circumferential groove 49 is arranged closer to the abutment means 42 than the second portion 90. The surface of the first portion 88 of the circumferential groove 49 preferably extends to the first surface 70 of the abutment means 42. The second point P2 of contact between the surface of the circumferential groove 49 and the common sphere 80 is situated in the second portion 90 of the circumferential groove 49. One of the radii 84, 86 may however also be zero, which means that surface will be substantially planar.

The common sphere 80 provided with a radius 82 is only an imaginary sphere, described to define the geometrical configuration of the circumferential groove 49 and the abutment means 42 arranged in and on the latch cone ring 14. Thus, the common sphere 80 is not a physical feature or part of the latch cone ring 14. When the latch cone ring 14 work together with the other parts of the synchronizing arrangement the spring-loaded balls 40 interact with the latch cone ring 14 as described above. Preferably, the spring-loaded balls 40 have a radius which substantially conforms to the radius 82 of the common sphere 80 in order to achieve said interaction.

After a gear shifting operation, which results in that the cogwheel 18 is released from the shaft 30, the sleeve 20 is returned to an initial position in which no axial force acting on the latch cone ring 14. The spring-loaded balls 40 will be pushed into the circumferential groove 49 and contact the surface of the circumferential groove 49 and the first surface 70 of the abutment means 42 analogously to the position of the common sphere 80 as described above. Hence, the spring-loaded balls 40 will lock the latch cone ring 14 in a fixed axially position in relation to the sleeve 20 and the inner cone ring 16. As a result, the axial position of the latch cone ring 14 will be defined when the sleeve 20 is in its initial position. Also, the latch cone ring 14 is prevented from moving axially in the space between the sleeve 20 and the inner cone ring 16, and therefore the latch cone ring 14 cannot come into contact with the inner cone ring 16. Thus, an increase in fuel consumption, wear of the friction surfaces of the latch cone ring 14 and the inner cone ring 16 and noise due to vibrations in the latch cone ring 14 are prevented.

Fig. 11 shows a side view of a synchronizing arrangement 12 provided with three cone rings 14, 16, 50 according to the invention. The cone rings 14, 16, 50 are a latch cone ring 14, an inner cone ring 16 and an intermediate cone ring 50. Such a synchronizing arrangement 12 may transmit a large amount of torque. The intermediate cone ring 50 has a substantially circular body 26 and is provided with two substantially circular friction surfaces 28, which both have a frusto conical shape. One of the friction surfaces 28 on the intermediate cone ring 50 interact with the friction surface 28 of the latch cone ring 14 and the other friction surface 28 on the intermediate cone ring 50 interact with the friction surface 28 of the inner cone ring 16. Both of the friction surfaces 28 on the intermediate cone ring 50 are provided with wear indication means 48. For clarity purposes the sleeve 20 is not disclosed in fig. 3, and for the same reason the latch cone ring 14, the inner cone ring 16 and the intermediate cone ring 50 are arranged on a distance from each other.

Fig. 12 shows a front view of a segment of a synchronizing arrangement 12 provided with four cone rings 14, 16, 92, 94 according to the invention. The synchronizing arrangement 12 comprises the latch cone ring 14, an inner cone ring 16 arranged on the side of a cogwheel 18, and a sleeve 20, which is axially displaceable by means of a shifter fork (not shown in fig. 12). A first intermediate cone ring 92 is arranged to interact with the latch cone ring 14 and a second intermediate cone ring 94 is attached to the inner cone ring 16.

The four cone rings 14, 16, 92, 94 are provided with interacting friction surfaces 28, which preferably are of a conical design. The axial force from the sleeve 20 acting on the latch cone ring 14 as described above to bring about a contact between the friction surfaces 28 on the cone rings 14, 16, 92, 94 during gear shifting.

When shifting gears in a gearbox 4 the cogwheel 18 is engaged and locked on a shaft 30 by means of the axially displaceable sleeve 20 and the hub 32 attached to the shaft 30 transmits torque between the shaft (not shown in fig. 12) and the sleeve 20.

The latch cone ring 14 is provided with at least one driver means 96 which interacts with the first intermediate cone ring 92. Preferably, there are a number of driver means 96 arranged and attached to the latch cone ring 14. The driver means 96 interact both radially and axially with the first intermediate cone ring 92, which is provided with an driving slot 98 for each driver means 96. The driver means 96 extends into the driving slot 98 and the torque from the latch cone ring 14 is transmitted to the first intermediate cone ring 92 via the driver means 96.

Fig. 13 shows a sectional view along line III - III in fig. 12. The axial force from the sleeve 20 to the latch cone ring 14 is also transmitted to the first intermediate latch cone ring 92 via the driver means 96. Both the driver means 96 and the driving slot 98 are provided with axially and circumferential directed driving surfaces 100, 102 which are in contact during the transmitting of torque and axially directed force, respective.

Thus, in order to initiate the synchronizing process and bring about contact between the friction surfaces 28 on the cone rings 14, 16, 92, 94 the axially force from the sleeve 20 is transmitted to the first intermediate cone ring 92 via the axially directed first driving surface 100 on the driver means 96 of latch cone ring 14 and the axially directed first driving surface 100 on the driving slot 98 of the first intermediate cone ring 92.

The sleeve 20 and the latch cone ring 14 interacts with means corresponding to the groove 49 and the spring-loaded balls 40 as described above in order to define the position of the latch cone ring 14 in relation to the sleeve 20. However, other kind of positioning defining means may be used, such as an annular curved wire instead of the spring-loaded balls 40. The positioning defining means 40, 49 is schematically depicted with dashed lines in fig. 13. The sleeve 20, the latch cone ring 14 and the inner cone ring 16 are provided with circumferential arranged teeth 36, 38 which are disclosed in fig. 12. The circumferential arranged teeth 36, 38 interact as described above during pre-synchronization and the synchronization process.

The first intermediate cone ring 92 is free to move axially within the gap formed between the second intermediate cone ring 94 and the inner cone ring 16. Also, the second intermediate cone ring 94 is free to move axially within the gap formed between the first intermediate cone ring 92 and the latch cone ring 14. However, the second intermediate cone ring 94 may be attached to the inner cone ring 16 and thus not free to move in the axially direction.

During the synchronization process the friction surface 28 on the latch cone ring 14 will act on the friction surface 28 on the second intermediate ring 94, simultaneously as the friction surface 28 on the first intermediate cone ring 92 will act on the friction surface 28 of the inner cone ring 16. The position of the cone rings 14, 16, 92, 94 will be defined during the pre-synchronization and the synchronization process since they act on each other friction surfaces 28. After a gear shifting operation, which results in that the cogwheel 18 is released from the shaft 30, the sleeve 20 is returned to an initial position in which no axial force acting on the latch cone ring 14. The spring-loaded balls 40 will be pushed into the circumferential groove 49 and contact the surface of the circumferential groove 49 and the first surface 70 of the abutment means 42 (shown in fig. 9). As a result, the axial position of the latch cone ring 14 will be defined when the sleeve 20 is in its initial position, which is described above. However, since the first intermediate cone ring 92 is arranged to move axially also the position of the first intermediate cone ring 92 must be defined after the gear shifting operation.

Fig. 14 shows a sectional view along line IV - IV in fig. 12. The driver means 96 extends into the driving slot 98 in the first intermediate cone ring 92. Preferably, the driving slot 98 is wider in the circumferential direction than the driver means 96, so that the driver means 96 is allowed to move both in the axial and in the circumferential directions in the driving slot 98. Both the driver means 96 and the driving slot 98 have interacting driving surfaces 100, 102 which are disclosed in fig. 14. The first driving surfaces 100 are directed and have a normal in the circumferential direction and the second driving surfaces 102 are directed and have a normal in the axial direction. The driver means 96 is on the first driving surfaces 100 provided with first engagement means 104 which are designed to interact with second engagement means 106 arranged in the first driving surfaces 100 on the driving slot 98 in the first intermediate cone ring 92. Preferably the first engagement means 104 on the driver means 96 are circumferential directed protrusions 104 and the second engagement means 106 on the driving slot 98 are preferably indentations 106 which extend in the circumferential direction of the first intermediate cone ring 92.

When the cogwheel 18 is released from the shaft 30 after a gear shifting operation, the sleeve 20 is returned to an initial position in which no axial force acts on the latch cone ring 14 and on the first intermediate cone ring 92. When the latch cone ring 14 is retracted the protrusion 104 on one of the first driving surfaces 100 will fall into the indentation 106 in the corresponding first driving surface 100 of the driving slot 98 in the first intermediate cone ring 92. Which of the protrusions 104 of the driver means 96 which will fall into the indentations 106 of the driving slot 98 depends on the direction of rotation of the shaft 30. When the protrusion 104 on the driver means 96 is arranged in the indentation 106 in the driving slot 98 the first intermediate cone ring 92 will be prohibited to move in the axial direction. As a result, the axial position of the first intermediate cone ring 92 will be defined when the sleeve 20 is in its initial position. According to an embodiment the driver means 96 may be provided with indentations 106 and the driving slot 98 may be provided with a protrusion 104.

As a result, the axial position of the latch cone ring 14 as well as the first intermediate cone ring 92 will be defined when the sleeve 20 is in its initial position. Also, the first intermediate cone ring 92 is prevented from moving axially in the space between the inner cone ring 16 and the latch cone ring 14, and therefore the first intermediate cone ring 92 cannot come into contact with the inner cone ring 16. Thus, an increase in fuel consumption, wear of the friction surfaces 28 of the first intermediate cone ring 92 and the inner cone ring 16 and noise due to vibrations in the first intermediate cone ring 92 are prevented.

The components and features specified above may within the framework of the invention be combined between the different embodiments specified.

Claims (18)

Claims

1. A latch cone ring for a synchronizing arrangement (12), comprising a substantially circular friction surface (28) with a central axis, and at least one latch tooth (36) arranged on a periphery (39) of the latch cone ring (14), characterized in that at least one driver means (96) is arranged on the latch cone ring (14), in that at least one engagement means (104, 106) is arranged on the at least one driver means (96), in that the at least one driver means (96) is provided with a first, axially directed driving surface (100) and at least one second, circumferential directed driving surface (102), and in that the at least one engagement means (104, 106) is arranged on the at least one second, circumferential directed driving surface (102).

2. A latch cone ring according to any of the preceding claims, characterized in that the at least one engagement means is a protrusion (104).

3. A latch cone ring according to claim 1, characterized in that the at least one engagement means is an indentation (106).

4. A latch cone ring according to any of the preceding claims, characterized in that at least one driving means (42) is arranged on the periphery (39) of the latch cone ring (14).

5. A latch cone ring according to claim 4, characterized in that the at least one driving means (42) comprises a first surface (70) with a normal (78) having a first angle (a) in relation to a centre line (44) of the latch cone ring (14), in that a circumferential groove (49) is arranged in a peripheral surface of the latch cone ring (14) adjacent to the first surface (70) of the at least one abutment means (42), and in that the at least one abutment means (42) and the circumferential groove (49) are so configured that one first point (P1) on the first surface (70) of the at least one abutment means (42) and one second point (P2) in the circumferential groove (49) are situated on a periphery of a common sphere with a radius (82).

6. A latch cone ring according to claim 5, characterized in that the circumferential groove (49) in a sectional view is provided with a first radius (84) arranged in a first portion (88) of the circumferential groove (49) and a second radius (84) arranged in a second portion (90) of the circumferential groove (49).

7. A latch cone ring according to claim 6, characterized in that the first radius (84) is smaller than the second radius (86).

8. A latch cone ring according to any of claims 6 - 7, characterized in that the first portion (88) is arranged closer to the abutment means (42) than the second portion (90).

9. A latch cone ring according to any of claims 6 - 8, characterized in that the second point (P2) is situated in the second portion (90).

10. A latch cone ring according to any of claims 5 - 9, characterized in that the first angle (a) is 10° - 80°, preferably 30° - 60°, most preferably 40 ° - 50 °.

11. An intermediate cone ring for a synchronizing arrangement (12), comprising a substantially circular friction surface (28) with a central axis, characterized in that at least one driving slot (98) is arranged on the intermediate cone ring (92), in that at least one engagement means (104, 106) is arranged on the at least one driving slot (98), and in that the at least one driving slot (98) is provided with a first, axially directed driving surface (100) and at least one second, circumferential directed driving surface (102).

12. An intermediate cone ring according to claim 11, characterized in that the at least one engagement means (104, 106) is arranged on the at least one second, circumferential directed driving surface (102).

13. An intermediate cone ring according to any of claims 11-12, characterized in that the at least one engagement means is an indentation (104).

14. An intermediate cone ring according to any of claims 11-13, characterized in that the at least one engagement means is a protrusion (106).

15. Synchronizing arrangement (12), characterized in that the synchronizing arrangement (12) comprises a latch cone ring (14) and an intermediate cone ring (92) according to the claims 1 and 11.

16. Synchronizing arrangement (12) according to claim 15, characterized in that the synchronizing arrangement (12) comprises a sleeve (20) in which at least one spring-loaded ball (12) is arranged, which spring-loaded ball (12) has a radius corresponding to the radius (82) of the common sphere (80).

17. Gearbox (4), characterized in that the gearbox (4) comprises a synchronizing arrangement (12) according to any of claims 15 - 16.

18. Vehicle (1), characterized in that the vehicle (1) comprises a gearbox (4) according to claim 17.