SYNCHRONIZER
Cross Reference to Related Requests This application, which has the attorney's file number 94-rELT-247, relates to U.S. Patent Applications Serial Nos.,,,,,; filed, and having respectively the attorney's file numbers 95-rELT-217, 95-rTRN-406, 91-TRN-499, 94-rELT-154, and 97-rTRN-259, and all assigned to the transferee of this application. Field of the Invention This invention relates to a synchronizer for a transmission. BACKGROUND OF THE INVENTION It is well known that synchronizers can be used in multiple speed ratio transmissions to help change all or some of the transmission gear ratios. It is also known that the effort of change and / or the time to carry out a change can be reduced by the use of synchronizers of the self-energizing or amplification type. As the operator's change effort is generally increased with the size of the vehicle, the auto-energizing type synchronizers are especially useful in transmissions for heavy-duty trucks and / or transmissions where reduced shift time is preferred. and / or reduced change effort. Examples of prior art synchronizers that may be relevant to the synchronizer herein may be seen by reference to U.S. Patent Nos. 5,078,245 and 5,092,439; Japanese Patent Publication (Koko U) 45-27483; and German Patent Publication No. 1,098,824, which are incorporated herein by reference. SUMMARY OF THE INVENTION An object of the invention is to provide a synchronizer with improved means for de-linking self-energizing media when a force of change is removed before a change is completed. According to the invention, a synchronizer is selectively operative to frictionally synchronize and positively connect a first mounted traction for rotation about an axis of a second traction. The synchronizer includes a first jaw member fixed at the first traction and engageable with a second jaw member axially movable in response to its engaging movement by an axial force of change (F0). The second jaw member is mounted for non-rotation and for axial movement relative to the second traction. A first friction member is secured for rotation with the first traction and a second friction member is axially movable towards frictional engagement with the first friction member to provide a synchronization torque between the tractions in response to the linking movement. A shift member axially moves the second jaw member and the second friction member towards said linkages in response to the change force (F0) applied to the shift member. First resilient media links the friction members with an initial force (FJ in response to the initial movement of the member changes from a neutral position by the force of change (F0) to produce an initial synchronization torsion. response to the initial synchronization torsion to prevent asynchronous attachment of the jaw members and to transmit the force of change (F0) to the linked friction members Self-energizing first and second means are operative, when linked, to reacting the synchronizing torsion to produce an additive force (Fa) in the direction of the change force (F0) to increase the bonding force of the linked friction members Second resilient means limit the additive force (FJ. third resilient means to return the member changes to the neutral position and unlink the auto ramp -energizing in response to the change force (FJ is being reduced to a value less than (FJ before a change is completed. BRIEF DESCRIPTION OF THE DRAWINGS The synchronizer of the invention is shown in the accompanying drawings, in which: Figure 1 illustrates a double action synchronizer in a neutral position and in sections along line 1-1 of Figure 2; Figure 2 illustrates the synchronizer of Figure 1 in sections along line 2-2 of Figure 1; Figure 3 illustrates an enlarged view of part of a pin component of Figures 1 and 2; Figures 4A, 4B and 4C are amplified views of a component of Figures 1 and 2; Figures 5 and 6 illustrate an amplified self-energizing component of Figures 1 and 2; and Figure 7 is a graphical representation of the axial forces and torsions acting on a shift tab of the synchronizer. The drawings are simplified omitting the background lines of the components thereof. Detailed Description of the Drawings The term "synchronizer", as used herein, will designate a clutch mechanism used to non-rotatably engage a selected ratio gear to an arrow or drive by means of a positive clutch in which the attempted engagement of the positive clutch until positive clutch members are brought to substantially synchronous rotation by a synchronizing friction clutch associated with the positive clutch. The term "self-energizing" or "amplification" will designate a synchronizing clutch mechanism, which includes ramps or cams or the like to increase the binding force of the synchronizing clutch relative to the synchronizing friction of the friction clutch. Looking now at the drawings, there is shown in detail a set of gears and synchronizer 10 including an arrow 12 to be mounted for rotation about a central axis 12a, axially spaced gears 14, 16, rotatably held on the shaft and secured against axial movement relative to the arrow by annular thrust members 18, 20, and a dual-action synchronizing clutch mechanism 22. The thrust members 18, 20 are axially retained in annular grooves 12b, 12c in notch teeth 13 of the arrow and are fixed against rotation relative to the arrow by a retaining pin 24 (Figure 2) disposed in a space between two of the teeth 13. The synchronizing mechanism 22 includes annular friction member portions 26, 28 and portions of limb member. jaw clutch 30, 32 integrally formed with the gears 14, 16, jaw clutch members 34, 36 having internal notch teeth 38, 40 mating slidable With the notched external teeth 13c integrally formed with the arrow 12 or otherwise fixed to it, a radially extending flange or change member 42, having opposite axially facing sides 42a, 42b, sandwiched between surfaces that axially facing 34a, 36a of the jaw members 34, 36, three self-energizing members 44 further explained hereinafter, spring rollers 46, 48, annular friction members or rings 50, 52 secured together by three circumferentially spaced pins 54 , which extend axially from each of the friction members and through openings 42c in the flange and three pre-energizing assemblies 56. Each pre-energizer assembly includes a spring 58 and a plunger 60, which reacts with surfaces defined by the sets of pin. Also, the number of self-energizing members 44, pin assemblies 54 and pre-energizer assemblies 56 may be greater or less than that disclosed herein. The pre-energizing assemblies may be different from the type shown herein, for example they may be of the split pin type. In addition, the synchronizing mechanism may be different from the pin type; for example, the synchronizing mechanism may be of the so-called beam ring type, such as for example disclosed in United States Patent No.
,544,727, which is incorporated herein by reference. As can easily be seen, the friction members 26, 50 and 28, 52 are matched to define friction clutches to synchronize the gears to the arrow before engagement of the jaw clutches. Cone clutches are preferred; however, other types of friction clutches can be used. The friction members 26, 28 can be fixed to the associated gears in any of several known ways. The friction members 26, 28 have internal cone friction surfaces 26a, 28c that respectively mate with external cone friction surfaces 50c, 52c. Friction surfaces 26a, 28a can be defined by any of several known friction materials fixed to the base member, for example pyrolytic carbon friction materials, such as those disclosed in U.S. Patent Nos. 4,700,823; 4,844,218; and 4,778,548. These patents are incorporated herein by reference. The pin assembly 54 is shown in greater detail in Figure 3. Each pin assembly includes an axially extending arrow member 62 rigidly securing annular friction members 50, 52 together, annular locking members 64, 66 slidably disposed in the body. arrow member 62 and axially spaced by an annular abutment portion 62a of the arrow member 62, and spring rollers 68, 70 interposed between friction members 50, 52 and blocking members 64, 66. Each blocking member includes a larger diameter 64a , 66a slightly smaller than the diameter of the flange openings 42c and a conical locking shoulder 64b, 66b extending radially outwardly from the axis of the arrow member and axially away from each other at predetermined angles. Here, the angles are set to operate both as blocking shoulders cooperating with blocking shoulders 42d, 42e of the flange openings 42c, and pre-energizing shoulders cooperating with angled surfaces 60a, 60b on the pre-energizing pistons. 60. Alternatively, the shoulders of blocking members 64, 66 may be as taught in the aforementioned U.S. Patent No. 5,092,439. The springs 68, 70 provide a flexible link between the friction clutches and the blocking shoulders. The stop portions of the arrow member 62a, when disposed within their respective flange openings 42c, allow limited rotation of the friction ring and rigid pin assemblies relative to the flange to effect linkage of the blocking shoulders. pin assembly with beveled blocking shoulders 42d, 42e defined around the flange openings. The pistons 60 are radially outwardly biased by the compression coil springs 58 disposed in slots 42f of the flange. The greater extension of the grooves extends, preferably but not necessarily, radially with respect to the axis of the arrow. The grooves also extend axially through the flange sides 42a, 42b, towards the flange openings 42c, and have ends 42g in their extension radially inwardly for the springs to react against. The radially inner portion of the springs can be retained by means not shown, such as pins, which extend radially outwardly from the slot ends. Each plunger 60 has a somewhat U-shaped cross section with a closed end defining a head portion having angled pre-energizing surfaces 60a, 60b to cooperate with the pin assembly shoulders 64b, 66b. The side walls of each plunger have surfaces 60c, 60d to slideably cooperate with the radially extending side wall surfaces of the slot 42f to retain the plunger in the circumferential direction. The piston side walls also have opposing axially facing surfaces 60e to cooperate slidably with radially extending end surfaces., which axially face 34a, 36a of the jaw members 36, 34 to retain the plunger in the axial direction. As previously mentioned, the jaw members 34, 36 include notched internal teeth 38, 40 that slidably mate with external notch teeth 13 attached to the arrow. The outer notches have involution flank surfaces 13a extending parallel to the arrow axis, and mating them with the flank surfaces of the jaw member notches prevents relative rotation therebetween. Self-energizing members 44, as best seen in Figures 1, 2 and 4A-4C, each include end portions 44a, 44b, an arcuate central portion 44c with a radially inwardly facing surface 44d having a set of self-energizing ramp 45 extending radially inward from there and surfaces facing circumferentially in opposite manner 44e, 44f. The central portion 44c extends through the axially aligned opening 34b, 36b in the jaw members and through an opening 42h in a radially internal extension of the flange 42. The self-energizing member 44 is axially slidable relative to the jaw members 34, 36, and flange 42 is retained against circumferential movement relative to the flange by surfaces 44e, 44f, which abut in circumferentially facing shoulders 42i, 42j of flange aperture 42h, and is free to rotating a limited amount in the jaw member openings 34b, 36b until the surfaces 44e, 44f make contact with circumferentially facing shoulders 34c of the jaw member openings 34b, 36b. The shoulders 34c of the jaw member 34 are shown in phantom lines in Figure 2. The spring rollers 46, 48 are maintained in a pre-loaded condition against the jaw members 34, 36 by the end portions of the self-limiting member. energizer 44a, 44b and anti-friction thrust sheaves 47, 49, which react against axially opposite ends of the jaw members 34, 36. The internal diameter of the thrust sheaves 47, 49 is received in annular recesses 44g, 44h in each self-energizing member 44 and axial movement towards each other is prevented by one shoulder of each recess to maintain the pre-loaded state of a spring when the other spring is compressed by self-energizing forces. Alternatively, the springs can not be pre-loaded and / or the thrust sheaves 47, 49 can be omitted or not restricted against axial movement. As will be explained hereinafter, a main function of the members 44 and the spring rollers 46, 48 is to limit the magnitude of the self-energizing additive axial force Fa provided by the ramp assembly 45. However, in the present may also retain the jaw members 34, 36 against axial movement relative to the shift tab 42. Other means may be used to axially retain the jaw members 34, 36, for example the H-shaped retaining members in the above mentioned United States Patent No. 5,092,439. As best seen in Figures 1, 2, 5 and 6, portions of the outer arrow teeth 13 are modified to provide one or more self-energizing ramp surfaces cooperating with a similar number of ramp surfaces defined by the assembly ramp 45 of the member 44. The ramp assembly and the ramp surfaces therein extend radially inwardly between axially extending spaces between the arrow notches 13. The ramp surfaces allow limited rotation of the self-energizing member 44 and the flange 42 in relation to the jaw members 34, 36 and the arrow 12, and react to the synchronization torsion between the cone clutches and the arrow to provide the self-energizing additive axial force Fa to increase the bonding force of the cone clutch linked through the blocking shoulders by an operator change force F0 applied to flange 42, thereby increasing the synchronization torque provided by the cone clutch. Ramp surfaces may be provided to increase the synchronization force for one or both gears and / or to increase the synchronization force in response to twisting in any direction, as found for changes at higher speed and at lower speed. More specifically, pairs of axially facing flank surfaces 13a of the notches 13 have portions removed to provide self-energizing or amplifying ramp surfaces 13b, 13c, 13d, 13e and axially extending surfaces 13f, 13g, 13h, 13i . Self-energizing or amplifying ramp surfaces 13b, 13c react respectively against self-energizing or amplifying ramp surfaces 45a, 45b on the ramp assembly 45 to provide the additive axial forces to increase or assist the gear synchronization rate 14 in response to twisting in any direction. The ramp surfaces 13d, 13e respectively react against ramp surfaces 45c, 45d to provide the axial additive forces for engagement 16 in response to the synchronization torque in either direction. The angles of the ramp surfaces? they can be varied to provide different magnitudes of additive axial force for changes at higher speed and lower speed and for high and low speed ratios. Also, if additive axial force is not preferred in one direction for one or more gear, the ramp surfaces may be parallel to the notch, i.e. effective ramp surfaces are not provided. The magnitude of the additive axial forces, as further explained hereafter, is also a function of the ratio of the average radii of the friction clutches and the self-energizing ramps. Accordingly, the magnitude of the additive forces for a given change force F0 applied to the shift flange 42 by a shift fork can be varied by varying the ramp angles and / or the ratio of average radii. When the flange 42 is in the neutral position of FIGS. 1 and 5, annular arrow member stop portions 62a having diameters less than the largest diameter of the blocking member 64a, 66b are radially aligned with their associated flange apertures 42c, and friction surfaces of the cone clutches are slightly spaced and are maintained in this spaced relationship by angled pre-energizing surfaces 60a, 60b of the plungers 60 acting on the blocking shoulders 64b, 66b by the force of the springs 58. The force The axial arrangement provided by the pre-energizing surfaces 60a, 60b is preferably sufficient to counteract any additive axial force on the flange 42 by the self-energizing ramps due to the viscous shear of the oil between the cone clutch surfaces. When it is desired to couple any gear to the shaft, an appropriate and not shown gear mechanism, such as that described in U.S. Patent No. 4,920,815, incorporated herein by reference, is connected to the outer periphery of the flange. 42 in a known manner to move the flange axially along the axis of the arrow 12 either to the left to engage the gear 14 or to the right to engage the gear 16. The shift mechanism can be manually moved by an operator by A link system can be moved selectively by an actuator, or it can be moved by means that automatically initiate the movement of the mechanism of changes and that also control the magnitude of the force applied by the mechanism of changes. When the shift mechanism is moved manually, the force is proportional to the force applied by the operator to a shift lever. Whether applied manually or automatically, the force is applied to the flange 42 in an axial direction and is represented by the length of the arrow F0 in Figure 7. The initial axial movement to the right of the flange 42 by the arrow force F0 is transmitted to the blocking members 66 and the springs 70 by the pre-energizing surfaces 60b to effect initial frictional bonding of the cone surfaces 52a, 28a with an initial force FL. The initial force Fx is determined by pre-energizing springs 58 for given angles of the pre-energizing surfaces. The initial frictional link (with the condition that there is an asynchronous condition and momentarily ignoring the effect of self-energizing cams) produces an initial clutch engagement force and an initial synchronization torsion, which ensures limited relative rotation between the flange 42 and the linked cone friction surfaces, and thus movement of the annular stop 62a of the arrow member 62 to the appropriate sides of the flange openings 42c to position the blocking shoulders 66b for engagement with flange locking shoulders 42d. The initial force Fx produces substantially no flexion of the springs 70. When the blocking shoulders are linked, the total force of change of the operator F0 on the flange 42 is transmitted to the friction ring 52 via the blocking shoulders and the pre-energizing assemblies. 56, which continue to provide initial strength F? r whereby the cone clutch is linked by the full force of change of the operator F0 to provide a resultant operator synchronization torsion T0. The springs 68, 70, when not fully compressed, provide a flexible link between the blocking shoulders and the friction clutches. This link can become a solid link when the springs are fully compressed or their bending is stopped by stops not shown. The operator synchronization torsion T0 is represented by the arrow T0 in FIG. 7. As the blocking shoulders are arranged at angles relative to the axial direction of the operator change force F0, they produce a counterforce or release torque, which is contrary to the synchronization torque of the cone clutch but of lesser magnitude during asynchronous conditions. Upon reaching substantial synchronism, the timing torsion falls below the unlocking torsion, whereby the blocking shoulders move the pins in concentric relation with the openings 42c to allow continued axial movement of the flange and engagement of the outer teeth jaw 36e of the jaw member 36 with jaw teeth 32a of the jaw member 32, thereby completing a shift towards the gear 16. Axial movement of the flange 42 to the left to positively synchronize and engage the gear 14 to the jaw member 36a. arrow 12 is analogous to the above, and the change is consummated when the jaw teeth 34a of the jaw member 34 mate with the teeth 30a of the jaw member 30. The jaw / jaw teeth can be configured as shown in FIGS. U.S. Patent Nos. 3,265,171 and 4,246,993, which are incorporated herein by reference. Still ignoring the effects of self-energizing ramps, the cone clutch torque provided by the force F0 is expressed by equation (1). T0 = F0 Rc μc / sin a where: Rc = average radius of the cone friction surface, μc = coefficient of friction of the cone friction surface, and a = angle of the cone friction surfaces. Looking now at the effects of the self-energizing ramp surfaces, the synchronization torsion T0, due to the axial force of change F0 applied by the operator, is of course transmitted to the flange 42 by the pin assemblies 54 and is reacted to arrow 12 through the self-energizing ramp surfaces. The self-energizing ramp surfaces, when they are linked, produce the additive axial force Fa acting on the flange in the same direction as the change force F0. The additive axial force Fa is applied to the friction surfaces linked through the blocking surfaces via a force path that includes the self-energizing ramp surfaces, the self-energizing member 44, any of the spring rollers 46 or 48, and axially against the flange 42 via any of the jaw members 34, 36. The spring-loaded sheaves allow sufficient axial movement of the self-energizing member 44 for the linked self-energizing ramp surfaces 45a, 45b, 45c or 45d to move it to a force balance position at the intersection of the self-energizing ramp surfaces 13b, 13c, 13d or 13e with axially extending surfaces 13f, 13g, 13h or 13i. When in this position of force balance, the maximum additive axial force Fa is limited to the force transmissible by the spring in the balance position as any further movement of the self-energizing ramp surfaces 45a, 45b, 45c, or 45d on the axially extending surfaces it does not generate additive axial force. Alternatively, the angles of the self-energizing ramps can be selected to provide a predetermined maximum force on the spring rollers 46, 48. The forces F0 and Fa are applied to the shift flange 42 in parallel and summed to provide a force total Ft, thereby further increasing the bonding force of the cone clutch to provide an additive torsion of synchronization Ta, which is added to the torsion T0 to provide a total torque Tt. The sum of the axial forces to link the cone clutch is F0 plus Fa and the sum of the synchronization torques that are being produced by the cone clutch is T0 plus Ta, as shown graphically in figure 7. springs 58, 46, 48, 68 and 70 are selected such that the minimum bending force of the springs 68, 70 is less than the additive force Fa plus the initial force Ft. With this spring force arrangement, the springs 68, 70 return the flange member 42 to the neutral position and disengage the self-energizing ramps in response to the force of change being removed or reduced to a value less than the initial force Fi while the blocking shoulders are still linked. The variables and the principal equations for calculating self-energizing ramp angles can be seen with reference to the aforementioned U.S. Patent No. 5,092,439. A pin-type synchronizer has been disclosed to illustrate the inventive material herein. The following claims are intended to cover inventive portions of the disclosed material and variations and modifications that are believed to be within the spirit of the invention. Still ignoring the effects of self-energizing ramps, the cone clutch torque provided by the force F0 is expressed by equation (1). T0 = F0 R0 μc / sin OI where: Rc = average radius of the cone friction surface, μc = coefficient of friction of the cone friction surface, and o¡ = angle of the cone friction surfaces. Looking now at the effects of the self-energizing cams, the synchronization torsion T0, due to the axial force of change F0 applied by the operator, is of course transmitted to the flange 42 by the pins 54 and is reacted to the arrow 12 through the self-energizing ramp surfaces. The self-energizing ramp surfaces, when they are linked, produce the additive axial force Fa acting on the flange in the same direction as the change force F0. The additive axial force Fa is applied to the friction surfaces linked through the blocking surfaces via a force path that includes the self-energizing ramp surfaces, the self-energizing member 44, any of the spring rollers 46 or 48. , and axially against the flange 42 via either of the jaw members 34, 36. The spring rollers allow sufficient axial movement of the self-energizing member 44 for the associated self-energizing ramp surfaces 45a, 45b, 45c or 45d to move it to a position of force balance at the intersection of self-energizing ramp surfaces 13b, 13c, 13d or 13e with axially extending surfaces 13f, 13g, 13h or 13i. When in this position of force balance, the maximum additive axial force Fa is limited to the force transmissible by the spring in the balance position as any further movement of the self-energizing ramp surfaces 45a, 45b, 45c, or 45d on the axially extending surfaces it does not generate additive axial force. The forces F0 and Fa are applied to the shift flange 42 in parallel and summed to provide a total force Ft, thereby further increasing the bonding force of the cone clutch to provide an additive torque twist Ta, which is added to the torsion T0 to provide a total torque Tt. The sum of the axial forces to connect the cone clutch is F0 plus Fa and the sum of the synchronization torques that are being produced by the cone clutch is T0 plus Ta, as graphically shown in Figure 7 The variables and the main equations for calculating self-energizing ramp angles can be seen with reference to the aforementioned U.S. Patent No. 5,092,439. A pin-type synchronizer has been disclosed to illustrate the inventive material herein. The following claims are intended to cover inventive portions of the disclosed material and variations and modifications that are believed to be within the spirit of the invention.