CN108138863B

CN108138863B - Lift synchronizer set with reduced axial length

Info

Publication number: CN108138863B
Application number: CN201680052242.2A
Authority: CN
Inventors: 古伊列梅·G·比亚焦; 约瑟瓦尔多·R·费尔南德斯
Original assignee: Eaton Corp
Current assignee: Eaton Corp
Priority date: 2015-07-22
Filing date: 2016-07-21
Publication date: 2020-07-10
Anticipated expiration: 2036-07-21
Also published as: BR112018001346A2; WO2017013621A1; CN111692228A; CN111692228B; BR112018001346B1; CN108138863A

Abstract

A synchronizer includes a hub having a lifter ramp, a synchronizer cone, a synchronizer ring, and a sliding sleeve. The sliding sleeve has a gear on an interior surface engageable with the synchronizer cone and the hub. The sliding sleeve includes a slot. An inner lock contains the synchronizer ring, causing the synchronizer ring to move in an axial direction when axial pressure is applied. An insert is positioned within the slot and has an inwardly radially extending pin. When the sliding sleeve is displaced in the axial direction, the insert moves axially and a pin travels along one of the lifting ramps causing the synchronizer ring to engage with the synchronizer cone causing the synchronizer ring and synchronizer cone to rotate at the same speed so that the sliding sleeve can be positioned over both the gear of the hub and the synchronizer cone.

Description

Lift synchronizer set with reduced axial length

Cross Reference to Related Applications

This application claims priority to U.S. provisional application No. 62/195,448 filed on 22/7/2015, the disclosure of which is incorporated in its entirety. U.S. patent application No. 14/661,305, which is incorporated herein by reference in its entirety, is disclosed as U.S. publication No. 2015/0192204.

Technical Field

The technical field relates generally to a multi-track shift mechanism for a manual compound transmission and in particular to an improved synchronizer for a manual compound transmission.

Background

Manual compound transmissions are used in a variety of vehicle applications. Such compound transmissions typically include a multi-speed main section containing a plurality of gears for various ranges and load transmission configurations.

Manual compound transmissions are typically located within a drive train adjacent to a main drive unit having at least one rotating drive shaft. These compound transmissions typically include a shifter or gear selector that extends from the transmission to interact with the operator. A compound transmission may include a rotating and sliding assembly configured to engage a desired gear set as an operator moves a shifter or gear selector. Specifically, in a manual compound transmission, through a gear selector, an operator selects the appropriate gear by pushing or pulling a shift lever to the desired shift gate. A rail selector fixed to the main range rail is configured to translate movement of the shift lever to the shift fork. The rail selector is secured to the main transmission rail by a roll pin extending through a center location of the rail selector. Action on the shift lever causes a set of shift rails to move at least one shift fork, which causes a shift collar or slider to slide over the appropriate rotating gear to synchronize and activate the desired gear range.

Shift quality is an important factor in manual compound transmissions when selecting a desired gear ratio range. When shifting from one gear to the next, depression of the clutch pedal causes the output shaft to disengage from the layshaft, where the two halves of the transmission still rotate at the same speed but separately. However, the next gear is smaller than the previous gear, and the second gear teeth therefore move faster than the teeth of the slider. Thus, at this stage, the next gear, countershaft and input shaft all rotate too fast in the shift. Thus, without the use of a synchronizer, if the slider is moved over the next gear, the gears will rub together, causing noise, inefficient gear shifting, and gear wear.

Therefore, synchronizers have been developed to reduce or eliminate the grinding of gears during a shift. Thus, when the shifter is pulled (to shift from the first gear to the second gear), the slider advances the synchronizer key. The key in turn advances the locking ring, which pushes the locking ring into the conical shaped portion of the gear. When the conical shapes engage, the locking ring acts as a brake that grips the gear and keeps the assembly rotating at the same speed. Thus, the two halves of the transmission are joined by friction of the conical shaped surface. The friction is generally sufficient to keep the free-floating assembly at the same speed, but insufficient to propel the vehicle.

The key and notch in the lock ring have teeth that align with the teeth of the gear. Thus, during continued shifting, the shifter is pushed into the gear that causes the slider to travel over the teeth on the lock ring while using the teeth to align the teeth on the slider with the gear teeth. This prevents misalignment so that the shifter can easily slide into the gear without grinding. Once the components are aligned, the clutch is released and power from the input shaft can be transmitted through the transmission.

However, when shifting between gears, the sliding sleeve causes the locking rings to engage each other individually. That is, the sliding sleeve is positioned in the first position to engage the first lock ring and the first cone. During shifting, prior to engaging the second lock ring with the second cone of the second gear, the sliding sleeve is axially shifted to disengage the first lock ring from the first cone at the first position. To do so, the sliding sleeve passes through a neutral position, which is a position in which neither lock ring is in conical engagement with its respective gear. This operation is inefficient because each shift of this operation involves a power interruption, which occurs before engagement of the cone that is disengaged in the next gear occurs during the power interruption. This design is also spatially inefficient because additional strokes are used to pass through the intermediate positions.

Accordingly, there is a need to provide a manual compound transmission system that allows for improved synchronization of closely-fitting components.

Drawings

FIG. 1 is a perspective view, not to scale, of a compound manual transmission with a housing partially broken away;

FIG. 2 is a perspective view of an exemplary range rail for a compound manual transmission;

FIG. 3 is a partial cross-sectional view of an exemplary rotation assembly;

FIG. 4 illustrates an exploded view of an exemplary synchronizer for an exemplary manual compound transmission;

FIG. 5 is a perspective view in cross section of a synchronizer assembly including a compact lift synchronizer;

FIG. 6 illustrates a cross-section of the tight lift synchronizer of FIG. 5;

FIG. 7 illustrates a plan view of the tight lift synchronizer of FIG. 5; and is

Fig. 8A-8E illustrate steps in synchronizer operation, with both cross-sectional and plan views of exemplary steps.

Detailed Description

Referring now to the following discussion and the drawings, illustrative methods of the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially cut away to better illustrate and explain the present disclosure. Additionally, the descriptions set forth herein are not intended to be exhaustive or otherwise limit the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.

Reference in the specification to "exemplary illustrations" and "examples" or similar language means that a particular feature, structure, or characteristic described in connection with the exemplary methods is included in at least one illustration. The appearances of the phrase "in the specification" or similar type language in various places in the specification are not necessarily all referring to the same description or example.

According to various exemplary illustrations described herein, a system is disclosed. Specifically, an exemplary synchronizer for a compound manual transmission is disclosed. The compound manual transmission includes an input shaft that may be configured to engage with a prime mover (not shown) and an output shaft that may include a yoke for engaging with a transmission member (not shown). A compound manual transmission includes a main shaft, a countershaft and a plurality of gears disposed in a transmission housing. The main shaft may be disposed between the input shaft and an end yoke, and the end yoke may be disposed at a rear of the compound manual transmission. The primary shaft may include a first plurality of gears disposed about the primary shaft and in rotational alignment with a second plurality of gears disposed on the secondary shaft. The shaft and gears are commonly referred to as a rotating assembly.

The shift lever may extend from a control tower configured on the shift lever housing, the control tower being attachable to an upper portion of the compound transmission housing. The shift lever housing may be configured to position the at least one shift rail proximate to the rotational assembly to slidably connect the shift lever and the at least one shift fork to the rotational assembly. At least one of the derailleurs can be configured with at least one dampening member for reducing or eliminating notches, run-outs or other problems that can create poor shift quality. The dampening member may be in the form of a spring, a low friction bushing, a linear ball bearing, or other known dampening member that may be configured on at least one shift rail. The connection between the shift lever and the rotation assembly allows the operator to select the desired gear set because the lever may be directly connected to a gear within the compound transmission. The at least one range rail may include a rail selector and at least one dampening member configured on a main range rail of the at least one range rail. By moving at least one shift rail, the shift fork may be engaged with at least one synchronizer for mating with a selected gear set, discussed in more detail below, which helps to extend the life of the compound transmission and minimize the drain that may be associated with gear changes.

A rotation assembly, including an input shaft, a main shaft, a countershaft, and a synchronizer, may be configured to transmit torque from the prime mover to the output yoke through a desired gear set. The main shaft may include a plurality of rack teeth that may be configured to engage a stationary hub of a synchronizer and ultimately a plurality of gears on a countershaft, which may be driven by the input shaft. The synchronizer may include at least one gear flange, at least one blocker or synchronizer ring, a stationary hub, a sliding sleeve, and a pre-energizer assembly. The flange, blocker, ring and hub all include teeth or cogs that are each cut into an outer diameter surface, and these teeth are configured to engage and mate with corresponding teeth or cogs that are cut into an inner diameter surface of the sliding sleeve. The teeth each have an engagement ramp that facilitates alignment with a corresponding ramp on the sliding sleeve teeth. Thus, in operation, when the ramps are indexed/aligned, and the synchronization phase begins. Further, the pre-exciter assembly may comprise at least one of a strut, a roller, a plunger, and a spring.

Typically, when the sliding sleeve is moved aside, it pushes the blocker ring against the target gear via a post or pre-energizer. When pushed against the desired gear cone, the blocker ring rotates (due to friction) until it hits the wall of the stationary hub. In this position, the engagement ramp may be aligned to a ramp disposed on the teeth of the sliding sleeve. Thus, in the case of bevel indexing/alignment, synchronization begins. Once synchronization is complete, the blocker ring mates with the sliding sleeve (via the ramp), which releases the sliding sleeve for advancement toward the gear. The sliding sleeve and the rack of the gear cone collide with each other and the racks are again tightly fitted due to the engaging action between the slopes, thereby completing the engagement. Thus, in operation, and the operator positions the shift lever to select a predetermined gear set. Gear selection is performed by manipulating the shift lever to slide the main range rail, thereby connecting the range rail to the synchronizer and ultimately to the gear. The rail selector provides a linear force that pushes or pulls the shift fork, thereby sliding at least a portion of the shift fork against an external engagement groove on the outer diameter of the sliding sleeve to synchronize and engage the desired gear set.

The disclosed system improves shift operations using synchronizers that include a lift ramp and a system architecture that enables synchronization immediately after the onset of disengagement of the opposing gears. This eliminates the intermediate position, thereby resulting in a reduction in the overall axial length.

Referring to FIG. 1, an exemplary compound manual transmission 100 is illustrated. The transmission 100 may include an input shaft 110 and an output shaft 112, the input shaft 110 may be configured to engage a prime mover (not shown), while the output shaft 112 may include a yoke 114 for engagement with a transmission member (not shown). The compound manual transmission 100 includes an output shaft primary shaft 116, a secondary shaft 118, and a plurality of

gears

120, 122 disposed about the

shafts

116, 118. The primary shaft 116 and the secondary shaft 118 are disposed within a transmission housing 124, the transmission housing 124 being positioned between and engaged with the input shaft 110 and the end yoke 114, the input shaft 110 being configured to extend forward of the transmission housing 124, and the end yoke 114 being configured to extend rearward of the transmission housing 124. The primary shaft 116 may include a plurality of gears 120 disposed about the primary shaft 116 and rotatably aligned with a plurality of gears 122 disposed on the secondary shaft 118. The input shaft 110, output shaft 112, primary shaft 116, and secondary shaft 118 may be supported by the housing 124 through a plurality of bearings. The main shaft 116 may include at least one synchronization unit or synchronizer 126 for engagement at a predetermined output speed.

With continued reference to fig. 1, the upper housing portion 128 may be configured to receive a shift lever housing 130. Further, a control tower 132 extends from the lever housing 130 to a lever 134. The control tower 132 may include a spider having axial adjustment elements to increase gear selection while reducing any lost motion in the shift lever 134. The shift lever housing 130 may be configured to hold and align the shift control system 136. The control system 136 may be configured to translate movement of the shift lever 134 to at least one shift fork 138(138', 138 ") to select a desired gear set from the plurality of

gears

120, 122 to determine an output. Further, the shift fork 138 may be configured to engage at least a portion of the synchronizer 126 to select a gear set.

Fig. 2 illustrates a detailed view of control system 136, and control system 136 may include at least one main range rail 210. The primary shift rail 210 can include a first end portion 212, an intermediate portion 214, and a second end portion 216. As illustrated, the control system 136 includes a plurality of shift rails. Specifically, range rail 218, range rail 220, and range rail 222. However, this illustration is merely an example, and any number of shift rails may be used. Further, each

range rail

218, 220, 222 may include a

respective shift fork

138, 138', 138 "as shown. The main range rail 210 may include an engagement mechanism 230 and a rail selector dampening assembly 260.

The engagement mechanism 230 may be used to interconnect the shift lever 134 with the main shift rail 210. The engagement mechanism 230 can be disposed on either the main shift rail first end 212 or the main shift rail second end 216 depending on the particular position of the control tower 132. The engagement mechanism 230 may be configured to receive a segment of the shift lever 134 and may include at least one adjustment mechanism 240. An adjustment mechanism 240 may be disposed on at least one side of the engagement mechanism 230 to help minimize or eliminate lost motion while improving shift quality. In addition, control tower 132 may include a spider to also facilitate increased gear selection while reducing or eliminating idle. The adjustment mechanism 240 may include a spring-biased member or brake plunger 242 configured to bias travel of the engagement mechanism 230 to improve shift definition and reduce lost motion of the shift lever 134, and the adjustment mechanism 240 may include a biasing plate 246, the biasing plate 246 having grooves and channels that replicate a biasing pattern for allowing the engagement mechanism 230 to maintain travel of the shift lever of a defined shift pattern.

Turning now to fig. 3, an exemplary rotation assembly 300 is illustrated and the present disclosure is incorporated into the rotation assembly 300. That is, for purposes of illustration, the discussion with respect to fig. 3 includes known synchronizer operation, having spatially inefficient operation, as operation includes engagement through the first gear and passage through an intermediate position prior to engagement with the second gear.

The rotary assembly 300 includes an input shaft 110 operatively connected to an output shaft 112, either directly or indirectly through a countershaft 118. The rotary assembly 300 may further include a first plurality of gears 120, a second plurality of gears 122, and at least one

synchronizer

126, 126', 126 ". The input shaft 110 includes a first end 302 for engagement with a prime mover (not illustrated) and a second hollow end 304 having an input gear 306 disposed on the end 304, and a bearing cavity 308 positioned in the end 304. The bearing cavity 308 is configured to support the main shaft 116 at a front end 310, and the bearing 312 supports the main shaft 116 at a rear end 314. The input gear 306 is externally configured to engage the front gear 316 on the countershaft 118. The input shaft 110 may be supported in the housing 124 by bearings 318, while the output shaft 112 may be supported in the housing 124 by the bearing cavity 308 and bearings 312. The secondary shaft 118 may be separately supported by a front bearing 320 and a rear bearing 322 disposed in the housing 124.

Bearings

308, 312, 318, 320, and 322 are not limited to a particular type or size, but may include tapered bearings, thrust bearings, roller bearings, ball bearings, needle bearings, or other types of known bearings.

Countershaft 118 may also include a front intermediate gear 324, a rear intermediate gear 326, and a rear gear 328, all of which may be fixedly connected to countershaft 118. Accordingly, the second plurality of gears 122 may include a front gear 316, a front intermediate gear 324, a rear intermediate gear 326, and a rear gear 328. The second plurality of gears 122 may be configured to transmit torque from the input shaft 110 to the first plurality of gears 120, the gears 120 may include a main front gear 330, a main intermediate gear 332, and a main rear gear 334 rotatably attached to the main shaft 116.

Gears

330, 332, and 334 may include roller bearings 336 disposed between

gears

330, 332, and 334 and main shaft 116. Roller bearing 336 may be a needle bearing that allows

gears

330, 332, and 334 to rotate about main shaft 116. Accordingly, the first plurality of gears 120 is rotationally aligned with the countershaft 118 and the second plurality of gears 122. The number of gears used is not limited to a particular set, but is determined by the size and design of the transmission. The

gears

120, 122 may be of any known gear design and are illustrated as helical gears.

The plurality of

gears

120 and 122 transmit torque from the input shaft 110 to the yoke 114 disposed on the main shaft 110 at the rear of the transmission 100. Thus, a torque flow path may be defined by the interaction between the input gear 306 in close fitting relation with the front gear 316 for transmission through the countershaft 118 or by the gear flange 338 of the synchronizer 126 for direct transmission through the main shaft 110. Fig. 3 illustrates that the rotation assembly 300 is not limited to the number of synchronizers 126 used to transmit that torque, as the front synchronizer 126' and the rear synchronizer 126 "may be included to provide additional torque paths through the secondary shaft 118 and the primary shaft 116. The synchronizers 126', 126 "are engaged with the main shaft 116 through a rack connection. Specifically, the main shaft 116 is used as a counter and intermediate rack 342 for transmitting torque from the synchronizers 126', 126 "and through the main shaft 116 to ultimately transmit rotational torque through the yoke 114. For illustrative purposes only, a general description of synchronizer 126 will be discussed in more detail below.

Referring to fig. 3 and 4, an exemplary synchronizer 126 and its operation will now be discussed in more detail. Synchronizer 126 may be included to provide smooth transitions between different shift stages and gear selections within compound manual transmission 100. The synchronizer 126 may be configured to eliminate the "run out" effect found at the time of shifting and felt by the operator in the shift lever 134. As illustrated in fig. 4, the synchronizer 126 may include a fixed synchronization hub 400 positioned between two blockers or synchronization rings 402. The synchronizer hub 400 and the synchronizer ring 402 are positioned between two separate gear flanges 404. Both the gear flange 404 and the timing hub 400 contain

internal racks

406, 408. Specifically, the synchronizing hub 400 includes an internal gear rack 406, the internal gear rack 406 configured to engage at least one of the gear racks 340, 332 on the main shaft 116. The gear flange 404 includes an internal rack 408, the internal rack 408 engaging a corresponding rack cut into the edges of the plurality of gears 120. The

racks

340, 332 provide positive engagement between the rotating components to transmit torque, as previously discussed.

In addition, the synchronizer hub 400, synchronizer ring 402, and gear flange 404 all contain external gear teeth 410 or other known drive features on the exterior surface of each. The external gear teeth 410 may engage with corresponding features or internal gear teeth 412 on the interior surface of the sliding sleeve 414. The internal gear teeth 412 may be disposed on an inner diameter 416 of the sliding sleeve 414, while a circumferential groove 418 may be disposed in an outer surface 420 of the sliding sleeve 414 to receive a portion of the shift fork 138. The sliding sleeve inner gear teeth 412 may be configured to mate with and be positioned radially around the synchronizer hub 400, synchronizer ring 402, and gear flange 404. The

gear teeth

410, 412 may be configured with reduced radial clearance to improve the notch condition as the sliding sleeve 414 begins to engage the gear flange 404.

In operation, the sliding sleeve 414 engages one of the synchronizing rings 402 when shifted axially by using the shift fork 138 within the circumferential groove 418. That is, during a shift, the sliding sleeve 414 is caused to move, for example, in the first direction 420, and the internal gear teeth 412 of the sliding sleeve 414 engage the external gear teeth 410 of the synchronizer hub 400. Continued movement of the sliding sleeve 414 causes a slight circular movement and alignment of the synchronizing ring 402 via the gear teeth 410 of the synchronizing ring 402 such that the outer gear teeth 410 of the gear flange 404 are likewise aligned. Continued movement of the sliding sleeve 414 thereby locks the hub 400 with the gear flange 404 such that the sliding sleeve 414 thereby carries torque from the main shaft 116, to the synchronizing hub 400, through the sliding sleeve 414, and to the gear flange 404. In this manner, the synchronizing ring 402 serves to align the outer teeth 410 of the synchronizing hub 400 with the flange 404, thereby preventing damage thereto. Traditionally, the synchronizer ring 402 is made of a soft material, such as brass, which ensures that wear will occur in the synchronizer ring 402 rather than in the more expensive synchronizer hub 400 or flange 404.

When shifting to another gear, such as another flange 404 toward the rear of the transmission, the above description reverses and causes the sliding sleeve 414 to move in the second direction 422, causing the flange 404 to disengage from the synchronizing hub 400, through an intermediate position in which the sliding sleeve 414 is positioned at a central location relative to each gear flange 404, and then continued movement of the sliding sleeve 414 causes the sliding sleeve 420 to engage the other flange 404 (also labeled flange 424 for clarity) in the same manner and using another other synchronizing ring 402 (also labeled synchronizing ring 426 for clarity).

Referring now to FIG. 5, a perspective view of a cross-section of an assembly 500 including the disclosed compact lifting synchronizer, the assembly 500 may be incorporated into a transmission such as the compound manual transmission 100. The assembly 500 includes a hub 502 and a sliding sleeve 504. The hub 502 is generally cylindrical in shape, having a central axis or defined axial direction 558, the hub extending in a circumferential direction 544. The assembly 500 also includes a first synchronizer cone 506 and a second synchronizer cone 508. The first synchronizer cone 506 and the second synchronizer cone 508 may also be referred to in the art as "dog bodies". The assembly 500 includes a first synchronizer ring 510 and a second synchronizer ring 512. The assembly 500 shows a group or set of components 514 in cross-section, as will be further discussed in fig. 6. Synchronization as will be further explained can be achieved using components 514, and it is contemplated that components 514 can be distributed around the circumference of assembly 500 at two, three, or more locations.

The first synchronizer ring 510 and the second synchronizer ring 512 include angled

tapered surfaces

554, 556 as shown, the angled

tapered surfaces

554, 556 correspond, mate, and engage the

angled surfaces

550, 552 of the first synchronizer cone 506 and the second synchronizer cone 508. The angled surfaces are substantially smooth and engage each other during the synchronization process. That is, the first synchronizer ring 510 abuts the first synchronizer cone 506 when pressure is applied to the first synchronizer ring 510 and to the right in the figure, and the second synchronizer ring 512 abuts the second synchronizer cone 508 when pressure is applied to the second synchronizer ring 512 and to the right in the figure. This friction operation enables each respective cone and ring to reach the same speed during operation, as will be further described.

FIG. 6 illustrates a cross-sectional view of the assembly 514, and FIG. 7 illustrates a perspective view of the assembly 514, however, FIG. 7 illustrates a view that also does not include a sliding bushing 504 (or an insert) as will be further discussed so that operation of the assembly 514 is visible, referring to both FIGS. 6 and 7 and also FIG. 5, torque is transferred from the hub 502 through the sliding bushing 504 to one of the first and

second synchronizer cones

506, 508 depending on the engagement of the assembly 514. in one example, the synchronizer rings 510, 512 are made of a soft material such as brass, which ensures that wear will occur in the synchronizer rings 510, 512 rather than in the more expensive synchronizer hubs 502 or

synchronizer cones

506, 508. the

synchronizer cones

506, 508 each include a generally L-shaped cross-section opposite each other while each has a

respective base

511, 513 and

leg

515, 517, a

respective leg

515, 517 at a given spacing and including at its free outer edge a respective gear tooth, 546, 512, or leg finger 522, and a corresponding angular lift pin 520, a pin 520, a pin 520, a pin, a.

During operation and axial movement of the sliding sleeve 504, the assembly 514 is engaged as follows. As shown in fig. 5, 6, and 7, the sliding sleeve 504 is positioned such that torque transfer occurs from the hub 502 and the gear teeth 542, through the gear teeth 540 to the sliding sleeve 504, up to the first synchronizer cone 506, the gear teeth 540 are at the same given spacing as the

gear teeth

546, 548 and on the exterior surface of the hub 502, the gear teeth 542 are on the interior surface of the sliding sleeve 504.

Gear teeth

546 and 548 on an outer circumference of each of the first and

second synchronizer cones

506 and 508 may also engage gear teeth 542 on an inner surface of the sliding sleeve 504. Thus, it should be appreciated that the gear teeth 542 have the following relationship: the relationship has comparable spacing and angular orientation such that gear tooth 542 is engaged with gear tooth 540 of hub 502 and with

gear teeth

546, 548 during the disclosed synchronizing operation. Thus, movement of the sliding sleeve 504 in the axial direction 558 causes the insert 526 with the pin 534 to also move axially 558, forcing the pin 534 into engagement with the lift ramps 536, 538 and with the corresponding angled engagement surface 532 of the inner lock 530, while causing the inner lock 530 to engage with the other of the synchronizing rings 510, 512. Thus, each synchronizing

ring

510, 512 has a limited axial degree of freedom to move 558 axially while engaging one of the synchronizing rings 510, 512 and disengaging the other.

Synchronization occurs during several steps illustrated in fig. 8A-8E. Each of fig. 8A to 8E includes a side view or a cross-sectional view and a corresponding plan view above the cross-sectional view. Each plan view of fig. 8A-8E is a plan view of the components visible in fig. 7, with the sliding sleeve 504 and insert 526 not shown so that the components below are visible.

Fig. 8A corresponds to the position of the assembly as illustrated in fig. 5, 6 and 7, and to the engagement of the hub 502 with the first synchronizer cone 506. That is, the torque transfer in fig. 8A is from the hub 502, through the slip sleeve 504, to the first synchronizer cone 506. The second synchronizer cone 508 does not engage and thus there is a relative speed between the two, as illustrated.

Disengagement of the first synchronizer cone 506 and engagement of the second synchronizer cone 508 begins in fig. 8B. That is, the sliding sleeve 504 is displaced to the right in fig. 8B by the operator during engagement of the shift lever 134, and as can be seen, the sliding sleeve 504 is at an axial position disengaged from the first synchronizer cone 506. Movement of the sliding sleeve 504 likewise moves the insert 526, which thereby causes the pin 534 to also be axially displaced. In the illustrated axial position, the strut pin 520 engages a first one of the dimples 528. As seen in the top view of fig. 8B, the system is pre-energized and the pin 534, labeled in fig. 8B, begins to travel along the lift ramp 536, causing the insert 526 to move axially by pressure on the pin 534.

Synchronization continues in fig. 8C. The hexagonal pin 534 engages the angled engagement surface 532 of the inner lock 530 and also engages the lifting ramp 536. Axial movement of the inner lock 530 causes decompression between the first synchronizer ring 510 and the first synchronizer cone 506. Continued movement of the sliding sleeve 504 to the right in the figure causes circumferential displacement of the insert 526 within the slot 524 as seen in fig. 6 because the second synchronizer ring 512 prevents any axial movement of the insert 526 by abutting the second synchronizer cone 508. The circumferential displacement thereby also causes the second synchronizer cone 508 to be circumferentially displaced due to the pressure between the second synchronizer ring 512 and the second synchronizer cone 508, which enables the gear teeth 548 on the second synchronizer cone 508 to align with the gear teeth 542 upon further axial displacement.

Continued axial movement of the sliding sleeve 504 increases the pressure between the second synchronizer ring 512 and the second synchronizer cone 508 while increasing the additional pressure between the second synchronizer ring 512 and the second synchronizer cone 508. The additional pressure stagnates or reduces relative motion between the sliding sleeve 504 and the second synchronizer cone 508. Thus, with relative motion between the sliding sleeve 504 and the second synchronizer cone 508 stopped and the gear teeth 548 on the second synchronizer cone 508 aligned with the gear teeth 542 of the sliding sleeve 504, the sliding sleeve 504 can slide its final distance (not shown) to engage the gear teeth 542 and the gear teeth 548. In this manner, synchronization (and shifting) is completed with the second synchronizer cone 508 engaging the sliding sleeve 504 and the sliding sleeve 504 engaging the hub 502.

Thus, a compound transmission shift mechanism or assembly 500 is disclosed that includes a hub 502 that receives power from the input shaft 110. The hub 502 includes external gear teeth 540 extending in a circumferential direction 544, the hub 502 having two lifting

ramps

536, 538 extending on an exterior surface of the hub 502. The first synchronizer cone 506 and the second synchronizer cone 508 each have

external gear teeth

546, 548. The

legs

511, 513 of each

synchronizer cone

506, 508 include angled

outer surfaces

550, 552. The first synchronizer ring 510 and the second synchronizer ring 512 include

angled surfaces

554, 556 that mate with

angled surfaces

550, 552 of the first synchronizer cone 506 and the second synchronizer cone 508. Sliding sleeve 504 includes gear teeth 542 on an interior surface thereof, gear teeth 542 of sliding sleeve 504 being engageable with

external gear teeth

546, 548 of first synchronizer cone 506 and second synchronizer cone 508, and gear teeth 542 being engageable with gear teeth 540 on an outer circumference of hub 502, sliding sleeve 504 having slot 524 in groove 522. The inner lock 530 contains each of the first synchronizer ring 510 and the second synchronizer ring 512, causing the first synchronizer ring 510 and the second synchronizer ring 512 to move in an axial direction 558 when axial pressure is applied to the inner lock 530. Insert 526 is positioned within slot 524, insert 526 having pin 534 extending therefrom. The strut spring 518 is configured to apply a force of the strut pin 520 against the insert 526.

When the sliding sleeve 504 is displaced in the axial direction 558, the hub 502 has its gear teeth 540 disengaged from the first synchronizer cone 506, the insert 526 is moved axially 558 to engage one of the pins 534 of the insert 526 with one of the surfaces 532 of the inner lock 530, one pin 534 travels along one of the two lift ramps 536 of the hub 502 causing the circumference 544 of the insert 526 to be displaced causing the angled surface 556 of the second synchronizer ring 512 to frictionally engage the angled surface 552 of the second synchronizer cone 508 causing the second synchronizer ring 512 and the second synchronizer cone 508 to rotate at the same speed such that the sliding sleeve 504 may be further axially positioned over both the gear teeth 540 of the hub 502 and the gear teeth 548 of the second synchronizer cone 508.

With respect to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of the processes, etc. have been described as being performed according to a certain order, the processes may be practiced with the steps performed in an order other than that described herein. Further, it is understood that certain steps may be performed simultaneously, that other steps may be added, or that certain steps described herein may be omitted. In other words, the description of the methods herein is provided for the purpose of illustrating certain embodiments and should in no way be construed as limiting the claimed invention.

Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided will be apparent upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should, in fact, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur to those technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation.

Thus, the disclosed system improves shift operations using synchronizers that include a lift ramp and a system architecture that enables synchronization immediately after the onset of disengagement of the opposing gears. This eliminates the intermediate position, thereby resulting in a reduction in the overall axial length.

Unless expressly indicated to the contrary herein, all terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technology as described herein. In particular, use of the singular articles such as "a," "the," "said," etc. should be understood to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

Reference in the specification to "one example," "an example," "one method," or "an application" means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example. The phrase "in one example" in various places in the specification does not necessarily refer to the same example each time it appears.

The present disclosure has been particularly shown and described with reference to the foregoing description, which is merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the descriptions of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and any novel and non-obvious combination of these elements may be claimed in this or a later application.

Moreover, the foregoing description is illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. The invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. The scope of the invention is not to be limited except by the following claims.

Claims

1. A synchronizer, comprising:

a cylindrical hub having a central axis extending in an axial direction, the cylindrical hub having external gear teeth extending in a circumferential direction about the central axis at a given pitch, the hub having opposed lift ramps defined on and extending radially inward from an outer surface of the hub;

two synchronizer cones each having a generally L-shaped cross section, each L-shaped cross section including a base and a leg, each leg including gear teeth at a free outer edge and at the given pitch of the outer gear teeth of the cylindrical hub, each base including a tapered angled surface extending in the circumferential direction and about the central axis;

two synchronizer rings having angled surfaces that mate with the angled surfaces of the two synchronizer cones, respectively;

a sliding sleeve at the given pitch of the outer gear teeth of the cylindrical hub and having gear teeth on an inner surface thereof engageable with the gear teeth of the two synchronizer cones and engageable with the outer gear teeth on an outer circumference of the cylindrical hub;

an insert mechanically engaged with the sliding sleeve, the insert having an inwardly radially extending pin caused to move along the central axis upon axial movement of the sliding sleeve; and

an inner lock having opposing engagement surfaces and having two grooves extending in the circumferential direction, each groove axially containing one of the two synchronizer rings.

2. The synchronizer of claim 1, wherein the opposing lift ramps extend substantially parallel to each other.

3. The synchronizer of claim 1, wherein the sliding sleeve includes an axially extending slot in which an extension of the insert is positioned.

4. The synchronizer of claim 3, wherein the axially extending slot is in a circumferential groove and the axially extending slot extends in the circumferential direction.

5. The synchronizer of claim 1, wherein the angled surfaces of the two synchronizer cones are on an outer circumference of each base.

6. The synchronizer of claim 1, wherein the pin is hexagonal.

7. The synchronizer of claim 1, wherein the opposing lift ramps extend at an oblique angle relative to the circumferential direction and relative to the axial direction.

8. The synchronizer of claim 1, wherein the pin extends radially inward from the insert.

9. The synchronizer of claim 1, wherein one of the pins is configured to engage one of the opposing engagement surfaces during the axial movement of the insert and the other of the pins is configured to engage one of the opposing lift ramps during the movement.

10. The synchronizer of claim 1, wherein when the sliding sleeve is displaced in the axial direction, the hub disengages its outer gear teeth from one of the two synchronizer cones, the insert moves axially to engage one of the pins of the insert with one of the opposing engagement surfaces of the internal lock, the pin engages along one of the opposing lift ramps of the hub causing circumferential displacement of the insert causing the angled surface of the other of the two synchronizer rings to frictionally engage the angled surface of the other of the two synchronizer cones causing the other of the two synchronizer rings and the other of the two synchronizer cones to rotate at the same speed such that the sliding sleeve can be further axially positioned at the outer gear teeth of the hub and the other of the two synchronizer cones Both of the gear teeth of each.

11. A synchronizer, comprising:

a cylindrical hub having a central axis extending in an axial direction, the cylindrical hub having external gear teeth extending in a circumferential direction about the central axis, the hub having opposing lift ramps defined on and extending radially inward from an exterior surface of the hub;

a pair of opposing synchronizer cones each having a generally L-shaped cross-section, the L-shaped cross-sections each including a base and a leg, each leg including a gear tooth at a free outer edge, each base including a tapered angled surface extending in the circumferential direction and about the central axis;

two synchronizer rings having angled surfaces that mate with the angled surfaces of the opposing synchronizer cones, respectively;

a sliding sleeve having radially inner gear teeth designed to mate with the gear teeth of each of the opposing synchronizer cones and with the outer gear teeth of the cylindrical hub;

an insert mechanically engaged with the sliding sleeve, the insert having an inwardly radially extending pin; and

an inner lock having opposing engagement surfaces and having two grooves extending in the circumferential direction, each groove axially containing one of the two synchronizer rings;

wherein:

the radially inner gear teeth mate with the gear teeth of one of the opposing synchronizer cones when the sliding sleeve is at a first axial position;

when the sliding sleeve is at a second axial position, the radially inner gear teeth of the sliding sleeve are disengaged from the gear teeth of both of the opposing synchronizer cones but are a close fit with the outer gear teeth of the hub, and axial movement of the sliding sleeve causes one of the pins of the insert to axially engage one of the opposing engagement surfaces of the inner lock;

continued movement of the sliding sleeve to a third axial position allows the pin engaged with the one engagement surface of the internal lock to move circumferentially such that friction causes circumferential movement of the other of the opposing synchronizer cones; and is

At a fourth axial position of the sliding sleeve, the radially inner gear teeth of the sliding sleeve mate with the gear teeth of the other of the opposing synchronizer cones.

12. The synchronizer of claim 11, wherein the opposing lift ramps extend substantially parallel to one another.

13. The synchronizer of claim 11, wherein the sliding sleeve includes an axially extending slot in which an extension of the insert is positioned.

14. The synchronizer of claim 13, wherein the axially extending slot is in a circumferential groove and the axially extending slot extends in the circumferential direction.

15. The synchronizer of claim 11, wherein the angled surfaces of the opposing synchronizer cones are on an outer circumference of each base.

16. The synchronizer of claim 11, wherein the pin is hexagonal.

17. The synchronizer of claim 11, wherein the opposing lift ramps extend at an oblique angle relative to the circumferential direction and relative to the axial direction.

18. The synchronizer of claim 11, wherein the pin extends radially inward from the insert.

19. The synchronizer of claim 11, wherein one of the pins is configured to engage one of the opposing engagement surfaces during the axial movement of the insert and the other of the pins is configured to engage one of the opposing lift ramps during the movement.

20. The synchronizer of claim 11, wherein the outer gear teeth of the cylindrical hub have the same pitch as the gear teeth of each of the opposing synchronizer cones and the same pitch as the radially inner gear teeth of the sliding sleeve.