BLOCKED JAW CLUTCH ASSEMBLY

Abstract: A blocked jaw clutch assembly (l56) of the type having sensor unblocking ramps (l76, l78, l80, l82) is provided with structure tending to cause the blocking torque friction surface (l88) carried by the blocker ring (l24) to frictionally engage the blocking torque friction member (l90) carried by the first jaw clutch member (l08, l64, l88) with a circumferentially non-symetrical axial force.

Description: Background of the invention This invention relates to a blocked resilient jaw clutch assembly for coupling a gear to a shaft according to the preamble of claim 1. A change speed transmission which comprises a jaw clutch assembly in accordance with the preamble of the main claim is shown in US-A-4 132 122. This compound transmission is of the splitter type. Other examples of compound transmissions of the splitter or range type or a combination thereof are shown in US-A-3 105 395, 3 648 546, 3 799 002, 2 932 988 and 3 229 551. The prior art compound transmissions,especially of the semi blocked splitter type are provided with a main transmission section which includes non-synchronized unblocked jaw clutch assemblies. With the blocked compound transmissions the main transmission section is provided with synchronized blocked jaw clutch assemblies. However, with both types of compound transmissions its auxiliary transmission section is provided with resiliently shiftable blocked jaw clutch assemblies wherein preferably the blocked jaw clutch assemblies are provided with complementary ramp members on the associated blocker and clutch members. The complementary ramp members cause the blockers to prevent non-synchronize engagement of the associated jaw clutch assemblies when the main transmission section is engaged but will allow the blocker to tend to rotationally move to a non-blocking position under the influence of a spring bias when the main transmission section is a neutral. These assemblies provide a relatively uncomplicated and reliable arrangement for a compound transmission which is shiftable with substantially the ease of a simple transmission and allow shifts to be completed with the vehicle in a static condition. The blocked jaw clutch assemblies utilized in such transmissions are required to perform two distinct tasks, namely maintain a blocked condition under certain non-synchronous and relatively high inertia conditions and to unblock, by causing a synchronous condition to occur, regardless of the initial relative rotational speeds of the clutch members, under certain relatively low inertia conditions. Under certain adverse conditions, the ramped, blocked jaw clutch assemblies of prior art tended to unblock at improper conditions resulting in the blockers ceasing to prevent a nonsynchronous or crash type jaw clutch engagement, which is undesirable. SUMMARY OF THE INVENTION In accordance with the present invention, the drawbacks of the prior art have been overcome or minimized by the features of Claim 1 which provide an improved blocked clutch assembly utilizing sensor unblocking ramps wherein the tendency of the blockers or sensors to move to an unblocking condition under improper (i.e. non-synchronous relatively high inertia) conditions is minimized or eliminated while retaining the ability of the ramps to cause the blockers to move to an unblocked condition under proper (i.e. relatively low inertia) conditions. The above is accomplished in one embodiment of the present invention by providing a plurality of arrays of blocking projections or teeth configured such that, at initial engagement of the blocker and clutch member, the resulting axial forces exerted between the blocker and contacted jaw clutch member are circumferentially non-symmetrical about the axes of rotation thereof sufficient to cause an initial relative tilting between the blocker and jaw clutch and/or relative radial displacement of the blocker ring and clutch members and/or localized contact between the blocking torque friction surfaces. The above may be accomplished by a multitude of structural modifications. By way of example, the arrays may be spaced circumferentially non-symmetrical about the axis of the blocker and/or clutch, or the pre-energizer ring may be non-symmetrically mounted in the blocker ring; or a non-symmetrical pre-energizer ring may be utilized and/or the blocking projections at one or more arrays may be axially offset and/or eliminated. The above improved structure has proven very satisfactory in tests and is believed to prevent improper unblocking because the nonsymmetrical contact of the blocking torque friction surfaces and/or relative tilting and/or radial displacement of the members results in an initial breakdown of the oil film on the blocking torque friction surfaces and thus, by creating a non-hydrodynamic bearing surface, allows an early establishment of blocking torque. Also, a relatively small friction force in a radial direction between the members, caused by the unbalanced radial components of the non-symmetrical forces acting on cone friction surfaces, may act in opposition to any premature unblocking force generated by the unblocking ramps. Briefly the invention is believed to provide the observed advantages by assuring that the blocking torque caused by the frictional engagement of cone surfaces on the blocker and first clutch member, which torque causes the blocker to tend to rotate with the first clutch member and thus properly clock relative to the second clutch member, is established at or prior to the time the ramp surfaces are urged into contact at initiation of a clutch engaging operation. Accordingly, it is an object of the present invention to provide an improved blocked jaw clutch assembly of the type utilizing sensor unblocking ramps. This and other objects and advantages of the present invention will become apparent from a reading of the detailed description of the preferred embodiment taken in view of the accompanying drawings. DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of a "4x3" twelve speed version of semi-blocked transmission with which the improved blocked jaw clutch assembly of the present invention is advantageously utilized. FIG. 2 is partial sectional view of the transmission on FIG. 1. FIG. 3 is a schematic illustration of the shift pattern of the transmission of FIG. 1 FIG. 4 is an enlarged fragmentary view, in section of one of the jaw clutch-blocker assemblies utilized in the auxiliary splitter section of the transmissions of FIG. 1. FIG. 5 shows the components of the blocker and jaw clutch fragmentarily in synchronous condition permitting shifting. FIG. 6 is a fragmentary view of the blocker of FIG. 4. FIG. 7 is a view taken in the direction of the arrows 7-7 in FIG. 6. FIG. 8 is a top view of the shift lever knob and master control of the transmission of FIG. 1. FIGS. 9A, 9B and 9C, respectively, illustrate the blocked jaw clutch assembly of the present invention in the neutral, preselect and gear engagement positions thereof. FIG. 10 is a sectional view of one embodiment of the blocked jaw clutch assembly of the present invention. FIG. 11 is a fragmentary sectional view of an alternate embodiment of the present invention. FIG. 12 is a plan view of a preenergizing ring for another alternate embodiment of the present invention. FIG. 13 is a schematic illustration of a blocker utilized in another alternate embodiment of the present invention. FIG. 14 is a schematic illustration of a blocker utilized in a further alternate embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the apparatus in detail, it will be recognized that a detailed disclosure of both the construction and operation of blockers and blocked or semi-transmissions utilizing same has been set forth and claimed in the above mentioned patents and reference is therefore made thereto for such details. Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words "upwardly", "downwardly", "rightwardly" and "leftwardly" will designate directions in the drawings to which reference is made. The words "forward" and "rearward" will refer respectively to the front and rear ends of the transmission as same is conventionally mounted in the vehicle, being respectively the left and right sides of the transmission as illustrated in FIG. 1. The words "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the device and designated part thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import. The term "compound transmission" is used to designate a transmission having a main transmission portion and an auxiliary transmission portion connected in series whereby the selected gear reduction in the main transmission portion may be compounded by further selected gear reduction in the auxiliary transmission port. The term "splitter type compound transmission" as used herein will designate a compound transmission wherein the auxiliary transmission is used to provide various selectable steps or subdivisions of the gear ratio selected in the main transmission port. In a splitter type compound transmission, the main transmission section is typically provided with relatively wide steps which are split or subdivided by the auxiliary section. The term "upshift" as used herein shall mean the shifting from a lower speed gear ratio to a higher speed gear ratio. The term "downwardly" as used herein shall mean the shifting from a higher speed gear ratio to a lower speed gear ratio. The terms "low speed gear", "low gear" and/or "first gear" as used herein shall all designate the gear ratio The term "blocked transmission" or "blocked transmission section" shall designate a change gear transmission or transmission section wherein a selected gear is nonrotatably coupled to a shaft by means of a positive clutch and a blocker is utilized to prevent such engagement until the members of the positive clutch are substantially synchronous, such synchronous condition achieved by manual and/or automatic manipulation of the transmission input and/or output shafts to cause a crossing of syncronous condition therebetween but not achieved by frictional contact of the selected clutch members sufficient to cause one of the clutch members, and the apparatus associated therewith, to rotate with the other clutch member. The term "synchronized transmission" shall designate a change gear transmission wherein a selected gear is non-rotatably coupled to a shaft by means of a positive clutch, attempted engagement of said clutch is prevented until the members of the clutch are synchronous and frictional means associated with the clutch members are sufficient, upon ititiation of a clutch engagement, to cause the clutch members, and all members rotating therewith, to rotate at a substantially synchronous speed of rotation. Referring now to Figures 1-3, there is illustrated a "4x3" twelve forward speed, semi-blocked, splitter type compound transmission 10. Transmission 10 comprises a main section 12 connected in series with an auxiliary section 14, each of which have a plurality of selectable speeds, or power paths. The main and auxiliary sections are both suitably enclosed by conventional housing means 16. While the blocked jaw clutch assemblies with sensor unblocking ramps of the present invention are especially well suited for use in connection with semi-blocked transmissions such as illustrated transmission 10, the assemblies are also advantageously utilized with other types of compound transmissions. The transmission 10 includes an input shaft 18 supported adjacent its rearward end by a bearing 20 and is provided with an input gear 22 nonrotatably connected thereto, as by splines. The input gear 22 simultaneously drives a plurality of main section countershafts at equal speeds. In the illustrated embodiment, the transmission is provided with two main section countershafts, 24 and 26, disposed on diametrically opposite sides of the mainshaft 28, which mainshaft is coaxially aligned with the input shaft 18 and is provided with a pilot portion 30 on its forward end rotatably received within and supported by the rearward end of the input shaft 18. The input shaft 18 is normally driven in one direction only by a primemover, such as a throttle controlled Diesel engine E through a selectively operated, normally engaged, friction master clutch C. Clutch C may be selectively disengaged by use of pedal P as is known in the prior art. Clutch C may have a known clutch-brake associated therewith. Each of the main section countershafts 24 and 26 is provided with an identical grouping of countershaft gears, such as the pair of gears 36, of identical size and number of teeth and disposed on diametrically opposite sides of the mainshaft 28. As may be seen by reference to FIG. 2, countershaft gears 42 and 44 may be defined by involute splines formed directly on the main section countershafts. A plurality of main section mainshaft drive gears 46, 48, 50 and 52 surround the mainshaft 28 and are selectably clutchable thereto, one at a time, by sliding clutch collars as is well known in the art. The main section mainshaft gears 46, 48 and 50 encircle the mainshaft 28, are in continuous meshing engagement with, and are floatingly supported by the diametrically opposite pairs of countershaft gears, 38, 40 and 42, respectively, which mounting means and the special advantages resulting therefrom are explained in greater detail in U.S. Pats. Nos. 3,l05,395 and 3,335,6l6, the disclosures of which are hereby incorporated by reference. The mainshaft gear 52 is the reverse gear and is in continuous meshing engagement with a pair of countershaft gears 44 by means of conventional intermediate idler gears (not shown). The forwardmost countershaft gears 36 are continually meshed with and driven by the input gear 22 for causing simultaneous rotation of the countershafts 24 and 26 whenever the input shaft is rotatably driven. Main section mainshaft gears 46, 48, 50 and 52; and main section countershaft gears 36, 38, 40, 42 and 44, and the idler gears, are all constantly meshed with and driven by the input gear 22 and thus, in combination, form the input gearing of the transmission l0. As may be seen, various abutment rings 54 are provided to axially fix the main section mainshaft gears relative to mainshaft 28. Sliding clutch collars 56, 58 and 60 are splined to mainshaft 28 for axial movement relative thereto and rotation therewith as is well known in the art. Sliding clutch 56 is axially slidable by means of shift fork 62 to clutch gear 52 to the mainshaft. Sliding clutch 58 is axially slidable by means of shift fork 64 to clutch either gear 50 or 48 to the mainshaft. Sliding clutch 60 is axially slidable by means of shift fork 66 to clutch gear 46 to the mainshaft or to clutch the input gear 22 (and thus the input shaft l8) to the mainshaft. Shift forks 62, 64 and 66 are attached to shift bars or rails, (only one, 68, of which is shown) of a known shift bar housing assembly 70 which is operated by a conventional shift lever 72. The present invention is also applicable to transmissions utilizing a remote mechanical, electrical or fluid shift mechanism in place of shift bar housing 70 and shift lever 72 and also to fully or semi-automatic transmissions and transmission systems such is that illustrated in United States Patent No. 4,36l,060. the disclosure of which is hereby incorporated by reference. Considering now the splitter auxiliary section l4,the mainshaft 28 extends thereinto and is coaxially arranged with and piloted into an output shaft 74 which is in turn supported within the housing l6 by suitable bearings generally indicated at 76. Said auxiliary section further includes a plurality of auxiliary section countershafts 78 and 80 each having an identical grouping of countershaft gears 84, 86 and 88 therein. As is known in the art and is illustrated in above-mentioned U.S. Patent No. 3,l05,395, to minimize the axial and transverse dimensions of a twin countershaft type compound transmission, the mainshaft section countershafts, 24 and 26, are displaced about 90° from the auxiliary section countershafts. Main section countershafts are supported in housing l6 by bearings 90 and 92 while auxiliary section countershafts, 78 and 80, are supported in housing l6 by bearings 94 and 96. Two auxiliary section mainshaft gears, l08 and ll0, encircle the mainshaft 28 and are constantly meshed with and floatingly supported by the auxiliary countershaft gear pairs 84 and 86, respectively. Output gear ll2 is splined to output shaft 74 for axial movement relative thereto and rotational movement therewith. Output gear ll2 is constantly meshed with auxiliary countershaft gear pair 88. Resiliently biased clutch members ll6, ll8 and l20 are splined to mainshaft 28 and, in combination with blockers (shown in FIG. 2) l24, l26 and l28, respectively, provide resilient, blocked clutching apparatus of the type described in above mentioned U.S. Pat. Nos. 3,799,002, 3,92l,469 and 3,924,484 for selectively clutching gears l08, ll0 and ll2, respectively, one at a time, to mainshaft 28. Clutch ll6 is biased axially by spring l30 and limited in its axial movement by positive stop l34. Clutch members ll8 and l20 are biased axially apart by spring l36 surrounding the mainshaft and limited in axial movement by stops l38 and l40. Gear ll2 is axially moved by shift fork l42 which is movable by shift cylinder assembly l44. Mainshaft gears l08 and ll0 are joined for joint axial movement and independent rotation by ring l46 and are axially movable by shift fork l48 movable by shift cylinder assembly l50. Shift cylinder assemblies l44 and l50 define a remote servo mechanism l52 by which gears l08, ll0 or ll2 are selectively engaged, one at a time, to mainshaft 28. Of course, engagement of gear ll2 to the mainshaft 28 is effective to couple mainshaft 28 direclty to the output shaft 74. Control of servo mechanism l52 is preferably, by a master control means, such as selector knob l54 (see FIG. 8) attached to the gear shift lever 72. typically, master control selector knob l54 will include a movable member, such as button 154A, or toggle lever, having three unique positions ("l", "2" and "3") by which one of the auxiliary section power paths, or speeds, may be selected. Typically, the auxiliary section master control l54, and the servo mechanism l52, is fluid and/or electrically operated and suitable master-slave valving and/or circuitry is provided. The details of the blocked, resiliently biased clutch-blocker assembly of the present invention may be seen by reference to FIGs. 4-7. The yieldable blocked jaw clutch structures are arranged between the shiftable mainshaft gears and the auxiliary section and are provided with resilient means for urging engagement thereof as set forth in detail in the above mentioned U.S. Pat. No. 3,799,002; 3,924,484 and 3,983,979. While clutch means utilizing relatively nondeformable blockers of the prior art are not identical with each other, they are generally similar and hence insofar as the present invention is concerned, it will be sufficient to describe only one of them in detail with the understanding that same may be applied to the other clutch units without difficulty by anyone skilled in the art. Therefore, for this purpose, referring to the positive jaw clutch unit positioned between the mainshaft gear l08 and the mainshaft 28 in the auxiliary transmission seciton l4, said jaw clutch unit is generally designated l56 and includes an annular clutch collar or clutch member ll6 encircling the mainshaft 28. Other means for mounting clutch collar ll6 to mainshaft 28 allowing relative axial but not rotational motion therebetween may be utilized. The clutch collar ll6 is provided with internal splines l58 which are disposed within corresponding external splines l60 provided on the mainshaft 28 for interconnecting the clutch collar ll6 to the mainshaft 28 for rotation therebetween. However, the cooperating splines l58 and l60 permit the clutch collar ll6 to freely slide axially relative to the shaft 28. A stop ring l34 is seated within a suitable groove formed on the external periphery of the shaft 28 and is disposed for contacting the clutch collar ll6 and limiting the rightward axial movement thereof. The collar ll6 is normally resiliently urged by means of a spring l30 into a butting engagement with the stop ring l34. The clutch collar ll6 is provided with external teeth l62 thereon which are adapated to meshingly engage the internal teeth l64 provided on the mainshaft gear l08. The internal teeth l64 form the other jaw clutch member of clutch assembly l56. The teeth l62 on the clutch collar ll6 are tapered, as at l66 and in a similar manner the leading edge of the teeth l64 on the mainshaft gear l08 are similarly tapered at l68. The tapered conical surfaces each extend at an angle of preferably between 30° and 40° relative to the longitudinal axis of the mainshaft 28. The exact degree of taper, and the advantages, thereof, are explained in detail in U.S. Pat. No. 3,265,l73. The other end of the spring l30 resiliently acts against a spring seat member l69 fixed to mainshaft 28. A selected number, here three, of the teeth 162 are partially removed for permitting the presence of a blocking ring as hereinafter further described. Such partial removal leaves, however, an axially shortened or partially removed tooth 170 for cooperation with the blocking ring. Referring now to the relatively nondeformable blockers; also called blocker rings, blocking rings and sensors; which are illustrated in FIGS. 6 and 7, one thereof is indicated generally at 124, and comprises a ring encircling the clutch member 116 and has an appropriate number, here three pairs, of radially inward projections 172 and 174, which when properly positioned will mate with the external teeth above mentioned. The inward projections or teeth 172 and 174 are contoured at their sides to lie snugly against the adjacent ones of the teeth 162, are positioned to project into the spaces between a partially removed tooth 170 and the teeth 162 on each side thereof. Each pair of projections 172 and 174 are circumferentially of less dimension than the corresponding circumferential spaces defined by partially removing teeth 170 and thus blocker ring 124 may be rotated in either a limited clockwise or counterclockwise direction relative to clutch member 116 from the position seen in FIG. 5 in which the space between teeth 172 and 174 aligns with partially removed tooth 170. Contact of either blocker tooth 172 or 174 by a clutch tooth 162 will limit such relative rotation and cause blocker 124 to rotate with clutch member 116. The space between the inwardly projecting teeth 172 and 174 is, however, of a clearance distance wider than the corresponding circumferential dimension of the tooth 170 so that when properly aligned at synchronism (or more accurately, when the relative speeds of the clutch components cross synchronism) the teeth l72 and l74 will straddle the tooth l70 and the clutch member ll6 can move axially through but not past blocker ring l24 to effect engagement with its corresponding gear. As may be seen by reference to FIGS. 6 & 7, the end faces of the blocker teeth l72 and l72 are tapered as at l76 and l78. The end face of partially removed tooth 70 is also preferably provided with tapers to ramps l80 and l82 complementary with the tapers or ramps l76 and l78 on the blocker ring blocking teeth l72 and l74. The angles l83 of the ramps l76, l78, l80 and l82 is selected such that the blocking teeth and the partially removed teeth will remain in proper blocked position when the main transmission section l2 is engaged but will tend, under a contacting force, such as spring 130 and/is actuator l50, if an auxiliary section shift has been selected, to cause the blocker and clutch to assume a nonblocking position (by causing relative rotational movement of the clutch ll6, blocker l24 and/or mainshaft 28) if the main transmission section is disengaged, i.e. in neutral. A ramp angle l83 of about l5° - 25°, preferably about 20°, relative to a plan P normal to the axis of rotation of the mainshaft 28 has proven highly satisfactory for most known semi-blocked transmission structures. As is described in greater detail by reference to above mentioned U.S. Pats. Nos. 3,92l,469 and 3,924,484, the radially inner side of ring l24 may be provided with an inwardly directed groove l84 which receives an annual resilient ring l86 which is normally of slightly less internal diameter than the external diameter of the teeth l62 so that when the parts are in the assembled condition, ring l86 is distorted slightly outwardly thereby to exert a light but definite pressure against the external surface of said teeth 162. Inasmuch as the ring 186 fits loosely and only in light frictional contact with the walls of the groove 184, this effects a significant resistance to axial movement between the blocker ring 124 and the clutch ring 116 but only an insignificant resistance to relative rotative movement therebetween. A suitable conical surface 188 projects radially outwardly from the blocker ring 124 and is positioned for engagement with a similar conical surface 190 on a radially inner wall of the gear 108. The axial drag above mentioned is sufficient that the rotative driving effect of the surface 190 onto the blocker 124 is much greater than whatever rotative resistance may exist between the blocker 124 and the clutch member 116. Surfaces 188 and 190 thus provide the blocking torque for the blocked jaw clutch assembly. A stop ring 192 limits movement of the blocker 124 away fromt the condical surface 190 when the clutch ring 116 moves out of engagement (leftwardly in FIG. 4). Referring to FIGS. 5-7, assuming that shaft 28, clutch member 116 and gear 108 are normally driven in the clockwise direction, it is apparent that the nonsynchronous condition comprising gear 108 rotating faster than shaft 28 and clutch 116 is sensed by engagement of tooth 170 with projection 174 while the opposite condition is sensed by engagement of tooth 170 with projection 172. Accordingly, projection 174 may be considered the overspeed or upshift projection while projection 172 may be considered the underspeed or downshift projection of the projection pair 172-174. The improved blocked jaw clutch assembly of the present invention may include a positive means to limit axial movement of clutch member 116 away from stop member l34. In Figure 4, the additional stop means illustrated is ring 200. Other means to limit axial movement of the clutch members ll6, ll8 or l20 may, of course, be utilized. The stop means is positioned such that, when the blocking arrays l70, l72 and l74 are in the blocking or non-aligned position, axial movement of clutch ll6, and gear l08 which is axially fixed thereto under such conditions, will be limited or stopped at less than the full leftwardly displaced position of the actuator l50. The operation and special advantages of the blocked clutched assembly of the present invention may be seen by reference to FIGURES 9A - 9C which illustrate the structure and operational function thereof. Briefly, FIG. 9A illustrates the neutral position, FIG. 9B illustrates the preselect position and FIGURE 9C illustrates the gear engaged position, of clutch assembly l56. Gear l08 is axially moved leftwardly against the bias of spring l30 by shift fork l48 and actuator l50. If engagement of gear l08 to mainshaft 28 is desired, gear l08 will be moved axially leftwardly to the position illustrated in FIGURE 9B the preselect position. In the preselect position, the blocking action of array members l07, l72 and l74, with blocker l24 in its blocking rotational position relative to clutch member ll6, will maintain clutch teeth l62 of the clutch member ll6 axially separated from clutch teeth l64 in gear l08. As the blocker l24, which tends to rotate with gear l08, is rotated relative to clutch ll6 to bring the arrays into alignment by causing gear l08 and shaft 28 to cross through synchroneous, the jaw clutch will become unblocked and, under the bias of compressed spring l30, fire into engagement with gear l08 as illustrated in FIGURE 9C. In the preselect position, as illustrated in FIG. 9B, it is important that the blocker l24 remain clocked in the blocking position relative to jaw clutch ll6 and only rotate relative to clutch ll6 to the aligned unblocked position as a result of the gear and clutch passing through synchronous. Under conditions of low mainshift inertia, i.e. mainsection l2 not engaged, the friction surfaces l88 and l90 will first cause the shaft 28 to rotate substantially synchronously with gear l08, and then the sensor unblocking ramps l76, l78, l80 and l82 will cause the blocker l24 to rotate relative to the clutch ll6 to a nonblocking position. The positioning function of the ramps is necessary as a crossing through synchronous, not merely achieving synchronous, is necessary to clock the blocker from a blocking to a non-blocking position. To assure that the action of the sensor unblocking ramps does not improperly act on the blocker, the blocker must be subject to blocking torque, i.e. the blocker ring l24 and first jaw clutch member (l08 and l64) must be properly frictionally engaged, at the blocking torque cones friction surfaces l88 and l90, to assure the blocker is frictionally urged to tend to rotate with the second jaw clutch member. If this frictional contact is not properly established and maintained, the sensor unblocking ramps may improperly cause the sensor l24 to rotate to an unblocked position relative to clutch member ll6. Referring to FIG. l0, a blocked jaw clutch assembly 2l0 of the type utilizing sensor unblocking ramps is illustrated. Jaw clutch assembly 2l0, except for a structural modification described below, is substantially structurally and functionally identical to the blocked jaw clutch assembly l56. Elements of assembly 2l0, and of the other alternate embodiments described herein having the same or substantially the same structure and function as elements of assembly l56 described above will be assigned like reference numerals. Assembly 2l0 includes a blocker or sensor ring l24 from which a plurality of sets or pairs of blocking teeth or projections extend radially inwardly. The three sets, l72 and l74, l72A and l74A, and l72B and l74B of ramped blocking teeth are spaced substantially circumferentially equally about the rotational axis 2l2 of blocker ring l24. An equal number of partially removed blocking teeth l70, l70A and l70B would, in the prior art, extend radially outwardly from jaw clutch member ll6 for blocking interaction with the blocking teeth carried by the blocker l24 to define three substantially equally circumferentially spaced arrays of blocking projections, 2l4, 2l4A and 2l4B. It has been discovered that the prior art blocked jaw clutch assemblies having sensor unblocking ramps thereon have a tendency, under certain unfavorable conditions, to improperly become unblocked. It has also been found, under experimentation, that this tendency can be minimized and/or eliminated by modifying the prior art structure to the structure 2l0 illustrated in FIG. l0 such that, upon initial contact of the arrays, the blocker l24 is caused to tilt and/or radially shift relative to friction cone l90 carried by gear l08, or at least non-symmetrical frictional contact between the friction cones l88 and l90 of the blocker member l24 and gear l08, respectively, is caused. Such tilting and/or radial shifting of the blocker and/or non-symmetrical frictional engagement between the cone surfaces is believed to minimize or eliminate undesirable unblocking because the non-symmetrical contact of the blocking torque friction surfaces and/or relative tilting of the members results in an initial breakdown of the oil film between the blocking torque friction surfaces and thus allows an early establishment of blocking torque on the blocker l24. Also, a relatively small friction force in the radial direction between the members may act in opposition to any premature unblocking force generated by the unblocking ramps. In any event, it is believed that the present invention provides the observed advantages by assuring that the blocking torque caused by the frictional engagement of the cone friction surfaces l88 and l90, which cause the blocker to tend to rotate with the first clutch member l64, is established and maintained at all times that the sensor unblocking ramps are in axial contact. The advantages of the present invention may be achieved by a multitude of structural modifications, several of which are illustrated in the Figures and discussed below by way of example only. Referring to FIG. l0, it may be seen, as illustrated in the dotted lines, that by removal of the normally present blocking tooth l70A extending from the clutch member ll6 and/or removal of the blocker teeth or projection pair l72A and l74A extending from the blocker l24, a blocked jaw clutch assembly will be provided wherein, upon contact of the remaining arrays, namely 2l4 and 2l4B, the resulting forces will tend to create a tilting action on blocker l24 and the friction cone surface l88 carried thereby as well as a non-symmetrical frictional contact between the cone friction surfaces l88 and l90. Of course, any arrangement of arrays that results in a circumferentially nonsymmetrical engagement of said arrays about the rotational axis 2l2 will have a similar advantageous effect. FIG. ll illustrates an alternate embodiment of the present invention wherein the groove 220 in which the preenergizing ring l86 is received is inclined rather than normal to the rotational axis 2l2 and thus the preenergizer ring l86 will tend to apply a tilt to sensor l24 and friction surface l88 carried thereby relative to the rotational axis 2l2 and cone friction surface l90 of gear l08. Referring to FIG. l2, a modified pre-energizing ring 2l6 having a non-symmetrical radially inwardly extending portion 2l8 is illustrated. Briefly, pre-energizing ring 2l6 will be received in pre-energizer groove l84 in sensor l24 in place of prior art pre-energizing ring l86. The action of the nonsymmetrical radially inwardly extending portion 2l8 on the outer radial periphery of the teeth l62 of jaw clutch member ll6 will cause the blocker l24 to be tilted relative to the axis of gear l08 and cone friction surface l90 carried thereby and/or will result in a nonsymmetrical circumferential engagement force between the cone friction surfaces l88 and l90. In FIG. l3 an alternate embodiment of the present invention utilizing a modified blocker ring 222 is illustrated. As may be seen, tooth l72, the downshift sensing tooth of array 2l4 is removed as is tooth l74A, the upshift sensing tooth of array 2l4A. Accordingly, during a downshift the arrays 2l4A and 2l4B will be effective while during an upshift arrays 2l4 and 2l4B will be effective. This provides the advantage of more evenly distributing any operating wear than would be the case if one of the arrays 2l4, 2l4A or 2l4B, were eliminated for both the upshift and downshift sensing directions of relative rotation. In FIG. l4, an alternate embodiment similar to that illustrated in FIG. l3 is illustrated utilizing a modified blocker 230. In blocker 230, the leading ramped surface l78 of upshift sensing blocker tooth or projection l74 of array 2l4 is cut back i.e. extends less axially rightwardly than do teeth l74A and l74B while the leading ramp surface l76A of upshift sensing blocker tooth l72A of array 2l4A is cut back. The ramp surfaces l76B and l78B, of blocking teeth l72B and l74B, respectively, of array 2l4B are not modified. Preferably, the cut back ramp surfaces are cut back by about ten thousandths (l0/l000) of an inch thereby assuring a tilting of the blocker member 230 and/or non-symetric circumferential engagement between the cone clutch surfaces at initial engagement of the arrays. As may be seen from the above, improved blocked jaw clutch assemblies with sensor unblocking ramps according to the present invention may be provided by a multitude of structural modification to the existing prior art devides as described and claimed in above mentioned United States Patent Nos. 3,983,797 and 3,924,484. Accordingly, by relatively simple modification of the prior art devices, improved blocked jaw clutch assemblies having sensor unblocking ramps, and blocked or semi-blocked transmissions utilizing same, are provided.

Claims: A blocked resilient jaw clutch assembly (156, 210) for coupling a gear (108) to a shaft (28), said blocked resilient jaw clutch assembly comprising a first jaw clutch member (164) fixed to said gear and defining a first set of clutch teeth and a second jaw clutch member (116) rotationally fixed but axially slidable relative to said shaft and defining a second set of clutch teeth (162) for engagement with said first set of clutch teeth, said second jaw clutch member (116) resiliently biased towards said first jaw clutch member (164), a stop means (134) fixedly secured to said shaft, spring means (130) normally resiliently urging said second jaw clutch member (116) against said stop means (134) when said gear (108) is in a first axial position and said first and second sets of clutch teeth are disengaged, a substantially nondeformable blocker ring (124) carried by said second jaw clutch member (116) for rotation therewith with a predetermied limited relative rotation therebetween, said blocker ring (124) axially movable relative to said second jaw clutch member in at least one axial direction, friction means comprising friction surfaces (188, 190) carried by said blocker ring (124) and said first clutch member (164), said friction surfaces adapted to be axially engaged at initiation of a clutch engagmeent operation whereby said blocker ring (124) is operable to tend to rotate with said first jaw clutch member (164) at initiation of a clutch engaging operation, said blocker ring (124) and second jaw clutch member (116) each having projections (170, 172, 174) extending therefrom defining an array (214) of interacting projections, said array of interacting projections effective to block relative axial movement of said second jaw clutch member (116) toward said first jaw clutch member (164) if not aligned, said blocker ring (124) having at least one rotational position relative to said second jaw clutch member (116) wherein said array (214) of projections are aligned and at least one rotatonal position relative to said second jaw clutch member (116) wherein said array of projections are not aligned, said blocker ring (124) effective to sense non-synchronous rotation of said clutch members (164, 116) corresponding to blocker ring rotation relative to said second jaw clutch member (116) sufficient to cause a non-alignment of said array (214) of projections to block axial engagement of said clutch members, movement of said gear (108) axially toward said second jaw clutch member (116) causing said array (214) to contact and move said second jaw clutch member axially away from said stop means (134) in opposition to said spring means (130) whereby said spring means will cause said second jaw clutch member (116) to again move axially in the opposite direction to meshingly engage said first set of teeth of said first jaw clutch member (164) when substantial speed synchronization is achieved therebetween, said array (214) having complementary ramps (176, 178, 180, 182) thereon which under the bias urging said array into axial contact, will tend to, cause said array to align, said assembly characterized in that said clutch assembly (156, 210) is arranged such that an axial force circumferentially assymetrical relative to the axis of rotation acts on said blocker ring (124) and urges said friction surfaces (188, 190) into contact at the initiation of engagement of said clutch assembly, whereby said blocker ring (124) tends to tilt thus enhancing the initiation of the breakdown of an oil film between the friction surfaces (188, 190). The assembly of claim 1 wherein said ramps (176, 178, 180, 182) define an angle of 15°-25° with respect to a plane normal to the axis of said shaft (28). The assembly of claim 1 wherein the arrangement is such that, an axial force urges said blocker ring (124) to move radially relative to said first clutch member (164) at initial engagement of said friction surfaces (188, 190). The assembly of claim 1 wherein the arrangement comprises a plurality of arrays of projections (214, 214A, 214B) unequally circumferentially spaced relative to the axis of rotation of said first clutch member (164). The assembly of claim 1 wherein the arrangement comprises a pair of spaced first blocker projections (172, 172A, 172B, 174, 174A, 174B) extending from said blocker ring (124) and second blocker projections (170, 170A, 170B) extending from said second jaw clutch member (116), each pair of first blocker projections comprising an overspeed projection (174, 174A, 174B) which will engage said second blocker projections (170, 170A, 170B) when said blocker ring (124) is caused to tend to rotate with said first jaw clutch member (164) and said first jaw clutch member is rotating faster than said second jaw clutch member (116) and an underspeed projection (172, 172A, 173B) which will engage said second blocker projections 170, 170A, 170B when said blocker ring (124) is caused to tend to rotate with said first jaw clutch member (164) and said first jaw clutch member is rotating slower than said second jaw clutch member (116), said arrays (214, 214A, 214B) being configured such that second blocker projection (170A) of one array (214A) will contact its associated underspeed first blocker projection (172A) while second blocker projection (170) of a different array (214) is not in contact with its associated underspeed first projection (172), and second blocker projection (170) of array (214), other than said array (214A), will contact its associated overspeed first blocker projection (174) while the second blocker projection (170A) of array (214A) is not in contact with its associated overspeed first blocker projection (174A). The assembly of claim 5, wherein the pairs of blocker projections (170, 170A, 170B, 172, 172A, 172B, 174, 174A, 174B) are substantially equally circumferentially spaced about the rotational axis of said second jaw clutch member (116) and said blocker ring (124). The assembly of claims 1 or 2, wherein said blocker ring (124) surrounds the-outer periphery of said second jaw clutch member (116) and includes a second friction means (186, 216, 220) for creating an axial frictional drag between said blocker ring (124) and said second jaw clutch member (116), said second friction means including an internal groove (220) within said blocker ring (124) and a friction ring (186, 216) contained within said groove (220) and bearing against a portion of the teeth (162) of said second jaw clutch member (116) in a circumferentially nonsymmetrical manner. The assembly of claim 7 wherein said groove (220) is non-perpendicular to the axis of rotation of said blocker ring (124). The assembly of claim 7, wherein said friction ring (186,216) defines a radially inwardly extending surface (218) having at least one portion of greater inward extension than the portion diametrically opposite thereto. The assembly according to the preceding claims, being provided together with a further resilient blocked jaw clutch assembly of corresponding design in an output component of a semi-blocked splitter type compound transmission comprising: an input component comprising an input shaft (18), an input gear (22) rotationally fixed to said input shaft, at least one first countershaft (24,26) carrying a plurality of first countershaft gears constantly meshed with said input gear (22) and a plurality of first mainshaft gears constantly meshed with other of said first countershaft gears; a connecting component comprising a mainshaft (28) and a plurality of first and second mainshaft clutch members 108, 110, 112, 116, 118, 120 rotationally fixed to said mainshaft, said connecting component independently rotatable of said input component; and an output component comprising an output shaft (74), an output gear (112) rotationally fixed to said output shaft, at least one second countershaft (78, 80) carrying a plurality of second countershaft gears thereon, one of said second countershaft gears constantly meshed with said output gear (112) and at least one second mainshaft gear (110) constantly meshed with another of said second countershaft gears, said output component independently rotatable of said connecting component; said input gear (22) and first mainshaft gears selectively clutchable one at a time to said mainshaft (28) by nonblocked nonsynchronized clutch means including said first clutch members, said output gear (112) and second mainshaft gear (110) selectively clutchable one at a time to said mainshaft (28) said blocked resiliently biased jaw clutch assemblies.

Inventors: RICHARDS, ELMER AARON
Applicants: EATON CORPORATION
Application year: 1987
Main classification: F16D23
IPC codes: F16H61, F16D23, F16H3