CA1248884A - Bracket assembly for a double wrap band - Google Patents
Bracket assembly for a double wrap bandInfo
- Publication number
- CA1248884A CA1248884A CA000489882A CA489882A CA1248884A CA 1248884 A CA1248884 A CA 1248884A CA 000489882 A CA000489882 A CA 000489882A CA 489882 A CA489882 A CA 489882A CA 1248884 A CA1248884 A CA 1248884A
- Authority
- CA
- Canada
- Prior art keywords
- band
- bracket assembly
- anchor
- apply
- bracket
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Braking Arrangements (AREA)
Abstract
BRACKET ASSEMBLY FOR A DOUBLE WRAP BAND
ABSTRACT
An improved bracket assembly for a double wrap brake band for the automatic transmission of an automo-tive vehicle wherein the band assembly is lightweight and heat set round at the released position. The bracket assembly comprises a transverse bar portion secured to parallel ends of the outer bands and the opposite end of the central band, an anchor portion secured to the opposite ends of the outer bands and an apply portion secured to the opposite end of the central band. The anchor portion has a centrally located anchor pocket formed in the bridging portion of the anchor portion to receive a single transmission pin perpendi-cular to the surface of the bracket, and the apply portion has an upwardly bent apply lip with a concave surface and angled side arms.
ABSTRACT
An improved bracket assembly for a double wrap brake band for the automatic transmission of an automo-tive vehicle wherein the band assembly is lightweight and heat set round at the released position. The bracket assembly comprises a transverse bar portion secured to parallel ends of the outer bands and the opposite end of the central band, an anchor portion secured to the opposite ends of the outer bands and an apply portion secured to the opposite end of the central band. The anchor portion has a centrally located anchor pocket formed in the bridging portion of the anchor portion to receive a single transmission pin perpendi-cular to the surface of the bracket, and the apply portion has an upwardly bent apply lip with a concave surface and angled side arms.
Description
BRACKET ASSEMBLY FOR A DOUBLE WRAP BAND
Description Conventional automatic transmissions transmit torque through what is commonly called a planetary gear system. Planetary gears are in constant mesh and thus cannot clash. They also provide, through arrest of the various gear carrying members, means for drive ratio and direction selection. Brake bands under suitable hydraulic controls are sometimes used to effect these changes. The bands provide a means of holding gear carriers and usually act as apply force multipliers. As the governing equation is exponential in nature, a so-called double wrap band may have more than twice the holding power of an otherwise similar single wrap band, at the expense of increased stroke, to full applied position.
Conventionally manufactured double wrap brake bands are formed from -a relatively thick metal strap, and a forging or casting is secured to the end~ of the strap to provide the apply bracket portions and a transverse tie for the band; the apply portions or ears being engaged by struts and by a hydraulic piston in the transmission to actuate the band. Once the bracket is welded to the strap, the band may be heat treated and the band assembly is expanded to size, the bracket is transversely~ broached or milled to form the transverse tie and apply ears, openings are pierced in the bottom wall of the slots, the interior surface of the band is prepared for bonding and a friction lini~g ~applied 0 thereto, openlngs are pier~ced ln the llning, the ;
, , ~ ~
`` ~2'~38~34 interior surface is bored and the lin~ng i9 grooved, and two circumferential slots are sawed through the lining strap and bracket except for the transverse tie, to result in the three generally parallel, radially expansible bands.
In commonly owned Canadian Patent No. 1,182,379 of February 12, 19~5 an improved double wrap band and bracket assembly and its method of formation is disclosed which obviates the disadvantages of the internal stresses created in previous bands that lead to distortion of the bands so they are out of round in the released position, thus creating undesirable friction drag between the band and clutch drum and uneven engagement of the band on the drum when actuated. The double wrap band of the above application utilizes a stamped slotted thin steel band with transverse tie portions and a stamped bracket with longitudinal tie portions secured thereto. A preslotted friction lining is applied to the interior of the band and bracket, and the tie portions are punched out to form the three parallel band portions having improved roundness in the open position and providing a uniform engagement thereof with the drum.
The present invention comprehends the provision of a bracket nssembly for a double wrap brake band which is formed from a stamped one-piece bracket member; the band and bracket being secured together andsubsequently separated into the bracket portions and three parallel bands.
The bracket assembly includes a central tran3verse bar portion3 an anchor portion and an apply portion; the anchor portion having a central raised bridging portion ~oining outer flanges wlth a single ; 2 .,. ~--:, :
`
~z~
reaction pocket formed in the bridging portion to receive a reaction or transmission pin of the transmis-sion. The apply portion has an upwardly folded apply ear to receive the end of a hydraulic piston or ~rod and angled side arms to aid in band orientation.
Further objects are to provide a construction of maximum simplicity, eficiency, economy, and ease of assembly, and such further objects, advantages and capabilities as will later more ful~y appear and are inherently possessed thereby.
Figure 1 is a top plan view of one form of a stamped slotted strap for the double wrap brake band.
Figure 2 is a side elevational view of the finished band and bracket assembly.
Figure 3 is a top elevational view of the finished band and bracket assembly before removal of the connect-ing ties.
Figure 4 is a cross sectional view of the bracket taken on line 4-4 of Figure 3.
Referring more particularly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, Figure 1 discloses one form of a preslotted stamped strap 10, utilized in the formation of the double wrap brake band, composed of outer bands 11 and 12 and a central band 13 of substantially equal widths for at least 50~ of the length of the strap. The strap has parallel longitudinally extending slots 14,14 interrupted by transverse ties~lS,15; with the ~slots diverging at 16~16 fo~-pproximately 25 to 50%~ ol .
;
:
. .
' ~8~
the strap length to provide a tapered central band portion 17 having an end 18 that is of a greater width than the normal band portion 13 and correspondingly narro~er outer band portions 19,19. The ends 21,21 of the narrow outer band portions extend beyond the center band end 18 and terminate in a width substantially equal to the width of the normal band portions. At the opposite end of the strap, the central band end 22 extends beyond the ends 23,23 of the outer bands.
A stamped one-piece anchor bracket 24 is utilized to join the opposite ends of the strap to form a circu-ar brake band 38. The bracket includes a central transverse bar portion 25 of a width e~ual to the strap width, an anchor portion 26 of the same width as the bar portion, and a centrally located apply portion 27; the apply portion and anchor portion being joined to the bar portion by longitudina~ly extending ties 280 The transverse bar portion 25 is suitably secured~ as by spot welding or brazing, to the ends 21,21 of the outer 20 bands 11,12 and the opposite end 22 of the central band 13.
The anchor portion 26 is secured to the ends 23,23 o~ the outer bands and has a raised bridging portion 29 rece ving thereunder the central band 13 adjacent the end 22 secured to tAe transverse bar portion; the bridging portion allowing ~or movement of the central band when the double wrap band is applied to the clutch drum or opened. A~so, the anchor portion is provided with a circular opening forming a self-centering anchor p~cket or seat 31 in the bridging portion ~9 adapted to receive a single reaction or transmission pin 34 that is generally perpendicular to the band. A transverse raised ridge 32 is formed in the anchor porti~n ~or the ' ~ ~8~
pocket 31 with the forward edge 33 of the pocket at the highest point of the ridge to provide more positive ~ contact with the reaction pin. ~his pocket 31 is positioned substantially in the center of the bridging portion 29.
The apply portion 27 is secured to the end 18 of the central band 13 opposite to end 22 and has an upwardly bent or folded ear or lip 35 cooperating with the end of a piston or strut (not shown) which is suitably actuated to engage the band on the clutch drum.
The lip has a concave surface 36 and oppositely angled side arms 37 to aid in orientation of the band to the strut.
The one-piece anchor bracket member 24 is formed into an arcuate member of substantially the same curva-ture as the curved band 10 and secured to the ends thereof to form a circular brake band assembly 38. The assembled unit is heat treated, formed and heat set to the desired diameter over an expanding fixture. A
preslotted friction lining 39 having longitudinally extending slots and transverse ties is bonded to the interior surface of the formed band by a suitable adhesive, the ties 28 joining the bracket portions are cut out, and then the ties 15 joining the bands of the strap and lining are removed by punching or other suitable operation to form the interconnected three bands of the final assembly 38.
As well as having better alignment of the bands and superior roundness for more uniform engagement and more complete release from the drum, the stamping of the preslotted band and the anchor bracket provides for tighter dimensional control of critical fit areas.
Stamping of the preslotted ba~nd and anchor bracket :
:
~2;~8~38~
allo~s use of materials that, when suitably processed, result in a higher strength to weight ratio and hence improved fatigue life over equal weight conventional double wrap bands. Tight dimensional control of this higher strength material results in improved fatigue life over conventional bands for equal space occupied.
Further, the anchor pocket 31 minimizes the effects of bracket/strap and bandJpin misalignment and allows design and manufacture of the seat with minimal stress risers or cracks. The use of the single central pocket provides a larger surface area for suitably securing the bracket to the straps and facilitates easy adjustment of band length by milling or other suitable means. Also, this design reduces the complexity and cost of the transmission anchor system and effectively captures the band. Although shown for a strap 10 having tapered portions toward one end, this bracket member 24 could obviously be applied to a strap having substantially parallel bands for the entire length of the strap.
- ' .
,. . . , ;
Description Conventional automatic transmissions transmit torque through what is commonly called a planetary gear system. Planetary gears are in constant mesh and thus cannot clash. They also provide, through arrest of the various gear carrying members, means for drive ratio and direction selection. Brake bands under suitable hydraulic controls are sometimes used to effect these changes. The bands provide a means of holding gear carriers and usually act as apply force multipliers. As the governing equation is exponential in nature, a so-called double wrap band may have more than twice the holding power of an otherwise similar single wrap band, at the expense of increased stroke, to full applied position.
Conventionally manufactured double wrap brake bands are formed from -a relatively thick metal strap, and a forging or casting is secured to the end~ of the strap to provide the apply bracket portions and a transverse tie for the band; the apply portions or ears being engaged by struts and by a hydraulic piston in the transmission to actuate the band. Once the bracket is welded to the strap, the band may be heat treated and the band assembly is expanded to size, the bracket is transversely~ broached or milled to form the transverse tie and apply ears, openings are pierced in the bottom wall of the slots, the interior surface of the band is prepared for bonding and a friction lini~g ~applied 0 thereto, openlngs are pier~ced ln the llning, the ;
, , ~ ~
`` ~2'~38~34 interior surface is bored and the lin~ng i9 grooved, and two circumferential slots are sawed through the lining strap and bracket except for the transverse tie, to result in the three generally parallel, radially expansible bands.
In commonly owned Canadian Patent No. 1,182,379 of February 12, 19~5 an improved double wrap band and bracket assembly and its method of formation is disclosed which obviates the disadvantages of the internal stresses created in previous bands that lead to distortion of the bands so they are out of round in the released position, thus creating undesirable friction drag between the band and clutch drum and uneven engagement of the band on the drum when actuated. The double wrap band of the above application utilizes a stamped slotted thin steel band with transverse tie portions and a stamped bracket with longitudinal tie portions secured thereto. A preslotted friction lining is applied to the interior of the band and bracket, and the tie portions are punched out to form the three parallel band portions having improved roundness in the open position and providing a uniform engagement thereof with the drum.
The present invention comprehends the provision of a bracket nssembly for a double wrap brake band which is formed from a stamped one-piece bracket member; the band and bracket being secured together andsubsequently separated into the bracket portions and three parallel bands.
The bracket assembly includes a central tran3verse bar portion3 an anchor portion and an apply portion; the anchor portion having a central raised bridging portion ~oining outer flanges wlth a single ; 2 .,. ~--:, :
`
~z~
reaction pocket formed in the bridging portion to receive a reaction or transmission pin of the transmis-sion. The apply portion has an upwardly folded apply ear to receive the end of a hydraulic piston or ~rod and angled side arms to aid in band orientation.
Further objects are to provide a construction of maximum simplicity, eficiency, economy, and ease of assembly, and such further objects, advantages and capabilities as will later more ful~y appear and are inherently possessed thereby.
Figure 1 is a top plan view of one form of a stamped slotted strap for the double wrap brake band.
Figure 2 is a side elevational view of the finished band and bracket assembly.
Figure 3 is a top elevational view of the finished band and bracket assembly before removal of the connect-ing ties.
Figure 4 is a cross sectional view of the bracket taken on line 4-4 of Figure 3.
Referring more particularly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, Figure 1 discloses one form of a preslotted stamped strap 10, utilized in the formation of the double wrap brake band, composed of outer bands 11 and 12 and a central band 13 of substantially equal widths for at least 50~ of the length of the strap. The strap has parallel longitudinally extending slots 14,14 interrupted by transverse ties~lS,15; with the ~slots diverging at 16~16 fo~-pproximately 25 to 50%~ ol .
;
:
. .
' ~8~
the strap length to provide a tapered central band portion 17 having an end 18 that is of a greater width than the normal band portion 13 and correspondingly narro~er outer band portions 19,19. The ends 21,21 of the narrow outer band portions extend beyond the center band end 18 and terminate in a width substantially equal to the width of the normal band portions. At the opposite end of the strap, the central band end 22 extends beyond the ends 23,23 of the outer bands.
A stamped one-piece anchor bracket 24 is utilized to join the opposite ends of the strap to form a circu-ar brake band 38. The bracket includes a central transverse bar portion 25 of a width e~ual to the strap width, an anchor portion 26 of the same width as the bar portion, and a centrally located apply portion 27; the apply portion and anchor portion being joined to the bar portion by longitudina~ly extending ties 280 The transverse bar portion 25 is suitably secured~ as by spot welding or brazing, to the ends 21,21 of the outer 20 bands 11,12 and the opposite end 22 of the central band 13.
The anchor portion 26 is secured to the ends 23,23 o~ the outer bands and has a raised bridging portion 29 rece ving thereunder the central band 13 adjacent the end 22 secured to tAe transverse bar portion; the bridging portion allowing ~or movement of the central band when the double wrap band is applied to the clutch drum or opened. A~so, the anchor portion is provided with a circular opening forming a self-centering anchor p~cket or seat 31 in the bridging portion ~9 adapted to receive a single reaction or transmission pin 34 that is generally perpendicular to the band. A transverse raised ridge 32 is formed in the anchor porti~n ~or the ' ~ ~8~
pocket 31 with the forward edge 33 of the pocket at the highest point of the ridge to provide more positive ~ contact with the reaction pin. ~his pocket 31 is positioned substantially in the center of the bridging portion 29.
The apply portion 27 is secured to the end 18 of the central band 13 opposite to end 22 and has an upwardly bent or folded ear or lip 35 cooperating with the end of a piston or strut (not shown) which is suitably actuated to engage the band on the clutch drum.
The lip has a concave surface 36 and oppositely angled side arms 37 to aid in orientation of the band to the strut.
The one-piece anchor bracket member 24 is formed into an arcuate member of substantially the same curva-ture as the curved band 10 and secured to the ends thereof to form a circular brake band assembly 38. The assembled unit is heat treated, formed and heat set to the desired diameter over an expanding fixture. A
preslotted friction lining 39 having longitudinally extending slots and transverse ties is bonded to the interior surface of the formed band by a suitable adhesive, the ties 28 joining the bracket portions are cut out, and then the ties 15 joining the bands of the strap and lining are removed by punching or other suitable operation to form the interconnected three bands of the final assembly 38.
As well as having better alignment of the bands and superior roundness for more uniform engagement and more complete release from the drum, the stamping of the preslotted band and the anchor bracket provides for tighter dimensional control of critical fit areas.
Stamping of the preslotted ba~nd and anchor bracket :
:
~2;~8~38~
allo~s use of materials that, when suitably processed, result in a higher strength to weight ratio and hence improved fatigue life over equal weight conventional double wrap bands. Tight dimensional control of this higher strength material results in improved fatigue life over conventional bands for equal space occupied.
Further, the anchor pocket 31 minimizes the effects of bracket/strap and bandJpin misalignment and allows design and manufacture of the seat with minimal stress risers or cracks. The use of the single central pocket provides a larger surface area for suitably securing the bracket to the straps and facilitates easy adjustment of band length by milling or other suitable means. Also, this design reduces the complexity and cost of the transmission anchor system and effectively captures the band. Although shown for a strap 10 having tapered portions toward one end, this bracket member 24 could obviously be applied to a strap having substantially parallel bands for the entire length of the strap.
- ' .
,. . . , ;
Claims (6)
1. A bracket assembly for use on a double wrap brake band having three parallel bands, comprising a transverse bar portion secured to two parallel ends of the outer bands and an opposite end of the central band, an anchor portion secured to the opposite pair of ends of the outer bands, and an apply portion secured to the one end of the central band, said anchor portion having a central bridging portion over the central band with an anchor pocket in the bridging portion for reception of a reaction pin.
2. A bracket assembly as set forth in Claim 1, in which said anchor portion has a transverse raised ridge within which said pocket is positioned.
3. A bracket assembly as set forth in Claim 1, in which said anchor pocket has its forward edge at the highest point of said ridge.
4. A bracket assembly as set forth in Claim 1, in which said anchor pocket is formed from a circular opening in said ridge.
5. A bracket assembly as set forth in Claim 1, in which said apply portion has an upwardly bent lip with a concave surface adapted to be engaged by the apply piston.
6. A bracket assembly as set forth in Claim 5, including oppositely angled side arms extending rear-wardly from the bent lip.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64760384A | 1984-09-06 | 1984-09-06 | |
| US647,603 | 1984-09-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248884A true CA1248884A (en) | 1989-01-17 |
Family
ID=24597616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000489882A Expired CA1248884A (en) | 1984-09-06 | 1985-09-03 | Bracket assembly for a double wrap band |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1248884A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5010986A (en) * | 1988-12-07 | 1991-04-30 | Daimler-Benz Aktiengesellschaft | Brakeband |
| US5078237A (en) * | 1990-06-28 | 1992-01-07 | Borg-Warner Automotive Transmission & Engine Components Corporation | Automatic transmission bands |
| US5083642A (en) * | 1990-01-25 | 1992-01-28 | Advanced Friction Materials Company | Double wrap friction brake band and method of manufacture |
| US5263557A (en) * | 1990-06-28 | 1993-11-23 | Borg-Warner Automotive Transmission & Engine Components Corporation | Anchor for automatic transmission bands |
| US5346040A (en) * | 1990-04-12 | 1994-09-13 | Borg-Warner Automotive Transmission & Engine Components Corporation | One-piece transmission band |
| US5347702A (en) * | 1990-06-28 | 1994-09-20 | Borg-Warner Automotive Transmission & Engine Components Corporation | Method of producing a transmission brake band |
| US5476160A (en) * | 1991-10-29 | 1995-12-19 | Borg-Warner Automotive, Inc. | Double-wrap brake band assembly |
| US5499700A (en) * | 1994-12-14 | 1996-03-19 | Borg-Warner Automotive, Inc. | Double wrap brake band with break-away ties |
-
1985
- 1985-09-03 CA CA000489882A patent/CA1248884A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5010986A (en) * | 1988-12-07 | 1991-04-30 | Daimler-Benz Aktiengesellschaft | Brakeband |
| US5083642A (en) * | 1990-01-25 | 1992-01-28 | Advanced Friction Materials Company | Double wrap friction brake band and method of manufacture |
| US5346040A (en) * | 1990-04-12 | 1994-09-13 | Borg-Warner Automotive Transmission & Engine Components Corporation | One-piece transmission band |
| US5078237A (en) * | 1990-06-28 | 1992-01-07 | Borg-Warner Automotive Transmission & Engine Components Corporation | Automatic transmission bands |
| US5263557A (en) * | 1990-06-28 | 1993-11-23 | Borg-Warner Automotive Transmission & Engine Components Corporation | Anchor for automatic transmission bands |
| US5347702A (en) * | 1990-06-28 | 1994-09-20 | Borg-Warner Automotive Transmission & Engine Components Corporation | Method of producing a transmission brake band |
| US5476160A (en) * | 1991-10-29 | 1995-12-19 | Borg-Warner Automotive, Inc. | Double-wrap brake band assembly |
| US5499700A (en) * | 1994-12-14 | 1996-03-19 | Borg-Warner Automotive, Inc. | Double wrap brake band with break-away ties |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |