SYNCHRONIZER BLOCKER PIN MOUNTING STRUCTURE

Abstract: A synchronizer assembly (10) having a clutch collar (12) disposed between axially spaced friction rings (15,16). Blocker pins (17) are mounted by a cylindrical shoulder (20) at one end thereof into cylindrical bores (21) formed in the friction ring (15). The cylindrical shoulder (20) has the same diameter as at least the portion of the blocker pin (17) immediately outwardly of the friction ring (15). The cylindrical bore (21) in the friction ring (15) has a bore (23) and the cylindrical shoulder (20) of the blocker pin (17) has a groove (22) formed therein. A locking pin (24) is pressed into the bore (23) to engage the groove (22) to lock the blocker pin (17) to the friction ring.

Description: This invention relates to synchronizers in general and more particularly to the structure for mounting the synchronizer blocker pins to the synchronizer friction ring of the synchronizer. GB-A-2008208 discloses a friction ring and blocker pin subassembly for a synchronizer assembly, including a friction ring having a bore formed therein and a blocker pin having a shoulder received in the bore. The conventional method most widely used for securing the blocker pin in its bore involves providing the blocker pin with a shoulder that rests against an outer end surface of the friction ring and with a reduced diameter portion passing through a hole in the ring and the outer end of the reduced diameter portion being peened or riveted in place. GB-A-2140515 discloses an arrangement by which an element such as a brake caliper slide pin is secured to a torque plate. The arrangement includes a draw key which is disposed in a bore extending transversely of the slide pin. The draw key is axially displaceable, from outside the torque plate, for engagement with, or disengagement from, a groove formed in the slide pin. According to the present invention there is provided a friction ring and blocker pin subassembly for a synchronizer assembly, including a friction ring having a first bore formed therein and a blocker pin having a shoulder received in the first bore characterized in that a second bore is formed in the friction ring, a portion of said second bore intersecting a portion of said first bore, and a groove is formed in the outer surface of the shoulder of the blocker pin, said groove being disposed in said intersecting portions of said first bore and said second bore, a pin being fitted as a press fit into said second bore and extending at least partially into said groove so as to secure the blocker pin positively to the friction ring. For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Fig. 1 is a longitudinal sectional view of a synchronizer assembly incorporating this invention with the blocker pins shown in full lines; Fig. 2 is an end view of the left hand friction ring of Fig. 1 when viewed in the direction of the arrow A in Fig. 1; and Fig. 3 is a cross-sectional view taken along the lines 3-3 in Fig. 1 to show a typical blocker pin mounting structure. Referring to Fig. 1, a synchronizer assembly 10 includes a clutch collar 12 therein. The collar 12 has a splined bore 14 which is conventionally splined onto a shaft (not shown). The assembly 10 also includes a left and right hand friction rings 15 and 16, respectively, which friction rings are adapted to be conventionally shifted into frictional engagement with gears (not shown) to bring the latter into synchronization with the shaft (not shown) and to allow the collar 12 to be clutched between the selected gear and the shaft by the splines 14. Means are provided to drivingly connect the left and right hand friction rings 15 and 16 to the collar 12 for unitary rotation and relative axial movement. More particularly; the left friction ring 15 has three blocker pins 17 secured thereto which blocker pins extend to the right therefrom to conventionally pass though registering openings, one of which is shown at 18, in the collar 12 while the right ring 16 has three blocker pins, one of which is shown at 19, which blocker pins extend to the left therefrom to conventionally pass through registering openings, one of which is shown at 13. The blocker pins 17 and 19 are secured to the friction rings 15 and 16 respectively. Referring to Figs. 1, 2 and 3 and the blocker pin indicated by the numeral 17 as illustrative of such securement, the blocker pin has a cylindrical shoulder 20 which is of uniform diameter and is pressed fit into a registering cylindrical bore 21 formed in the friction ring 15; the bore being approximately .0005" to .0015" smaller than the diameter of the shoulder 20 to provide for a pressed fit engagement therebetween. The shoulder 20 within the bore 21 has a circumferential groove 22 formed therein, which as seen in Figs. 2 and 3, is in registration with a second bore 23 which tangentially intersects the bore 21. A roll pin 24 is pressed into the second bore 23 and engages in the groove 22 to lock the blocker pin 17 within the bore 21 and prevent relative movement therebetween. Pins 19 are likewise locked into bore 25 in ring 16, and it should be noted that the cylindrical shoulder 26 is the same size both within the cylindrical bore 25 and at least for the first increment thereof external of the bore 25. For the blocker pin 17, the cylindrical shoulder 20 is the same diameter both within and out of the bore 21. This non reduction in size at the juncture of the shoulder 20 and the ring 15 and at the juncture of the shoulder 26 and the ring 16 provides for maximum strength of the blocker pins 17 and 19 at this location. This maximum size in cooperation with the roll pin attachment provides for a strong and durable connection between the blocker pins 17 and 19 and the friction rings 15 and 16 respectively.

Claims: A friction ring and blocker pin subassembly for a synchronizer assembly (10), including a friction ring (15, 16) having a first bore (21, 25) formed therein and a blocker pin (17, 19) having a shoulder (20, 26) received in the first bore (21, 25), characterized in that a second bore (23) is formed in the friction ring (15, 16), a portion of said second bore (23) intersecting a portion of said first bore (21, 25), and a groove (22) is formed in the outer surface of the shoulder (20, 26) of the blocker pin (17, 19), said groove (22) being disposed in said intersecting portions of said first bore (21, 25) and said second bore (23), a pin (24) being fitted as a press fit into said second bore (23) and extending at least partially into said groove (22) so as to secure the blocker pin (17, 19) positively to the friction ring (15, 16). A subassembly as claimed in claim 1, characterized in that the blocker pin (17, 19) is one of a plurality of blocker pins (17, 19) secured in respective first bores (21, 25) formed in the friction ring (15, 16) by respective pins (24). A subassembly as claimed in claim 1 or 2, characterized in that the or each pin (24) is a roll pin. A subassembly as claimed in any one of claims 1 to 3, characterized in that the friction ring (15, 16) is one of two friction rings having similarly secured blocker pins (17, 19). A subassembly as claimed in claim 4, characterized in that an axially movable clutch collar (12) is disposed between the friction rings (15, 16) and has a plurality of openings (13, 18) formed therethrough for permitting the respective blocker pins (17, 19) to pass therethrough.

Inventors: LOEFFLER, JOHN M.
Applicants: DANA CORPORATION
Application year: 1988
Main classification: F16D23
IPC codes: F16B21, F16B1, F16D23