CA1248883A - Bracket assembly for a double wrap band - Google Patents
Bracket assembly for a double wrap bandInfo
- Publication number
- CA1248883A CA1248883A CA000489881A CA489881A CA1248883A CA 1248883 A CA1248883 A CA 1248883A CA 000489881 A CA000489881 A CA 000489881A CA 489881 A CA489881 A CA 489881A CA 1248883 A CA1248883 A CA 1248883A
- Authority
- CA
- Canada
- Prior art keywords
- bracket assembly
- band
- apply
- anchor
- set forth
- 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 in 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 free end of the central band. The anchor portion has a pair of oppositely outwardly opening anchoring notches or pockets receiving the ends of anchor struts, and the apply portion has an upwardly bent apply lip with a concave surface for the apply piston and a side bumper.
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 in 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 free end of the central band. The anchor portion has a pair of oppositely outwardly opening anchoring notches or pockets receiving the ends of anchor struts, and the apply portion has an upwardly bent apply lip with a concave surface for the apply piston and a side bumper.
Description
~2~38~33 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 hy-draulic 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 ends of the strap to provide the apply and anchor bracket portions and a transverse tié for the band; the apply and anchor 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 lining applied thereto,~openings are pierced in the lining, the interior surface is bored and the lining is grooved, and two circumferential slots are sawed :, : ~
:
~248~383 through the lining strap and bracket except for the transverse tie to result in the three generally parallel radially expansible bands.
In commonly assigned Canadian Patent No. 1,182,379 of February 12, 1985, 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. ~ 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 assembly for a double wrap brake band which is formed from a stamped one-piece bracket member; the band and bracket being secured together and subsequently separated into the bracket portions snd three parallel bands.
The bracket assembly includes a central ~ransverse bar portion, an anchor portion and an apply portion; the anchor portion having a central raised bridging portion joining outer flanges with~anchor pocket~ formed in the side edges of the flanges to ~ 2 '`~ ~.`'. :
; :
`
receive the anchor members of the transmission. The apply portion has an upwardly folded apply ear to receive the end of a hydraulic piston or rod and an integral side bumper to aid in band orientation.
Further objects are to provide a construction of maximum simplicity, efficiency, economy, and ease of assembly, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.
Figure 1 is a partial side elevational view of the double wrap brake band and bracket assembly.
Figure 2 is a top elevational view of the finished band and bracket assembly.
Figure 3 is a top elevational view of the bracket assembly before removal of the connecting ties Figure 4 is a partial cross sectional view of the bracket taken on line 4-4 of Figure 3.
Figure 5 is a cross sectional view of the bracket taken on the line 5-5 of Figure 3.
Referring more particu~arly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, Figures 1 and 2 disclose a double wrap brake band and bracket assembly 10 formed of outer bands 11 and 12 and a central band 13 of substan-tially equal widths joined by a bracket assembly 14, :
;' '' : , ~ ~, ~2~ 83 shown in Figures 3 through 5. The double wrap band is formed from a preslotted stamped strap having longitu-dinally spaced ties that are removed to provide the parallel separate bands, and a preslotted friction lining 15 is applied to the strap and bracket assembly and has transverse removable ties.
The stamped one~piece anchor bracket 14 is utilized to join the opposite ends of the strap to form a circu-lar brake band 10. The bracket includes a central transverse bar portion 16 of a width equal to the strap width, an anchor portion 17 of the same width as the bar portion, and a centrally located apply portion 18; the apply portion and anchor portion being joined to the bar portion by longitudinally extending ties 19. The transverse bar portion 16 has a staggered cross over section 20 and is suitably secured, as by spot welding or brazing, to the ends 21,21 of the outer bands 11,12 and the opposite end 22 of the central band 13. The staggered cross over section 20 allows extension of the apply nose of portion 18 while maintaining the desired locked-up gap.
The anchor portion 17 is secured to the ends 23,23 of the outer bands and has a raised bridging portion 24 joining the outer flanges 25,25 and receiving thereunder the central band 13 adjacent the end 22 secured to the transverse bar portion; the bridging portion allowing for movement of the central band when the double wrap band is applied to the clutch drum or opened. ~lso, the anchor portion is provided with substantially U-shaped anchor pockets 26 which extend inwardly from the outer edges 27 of flanges 25 of the portion and are aligned with the outer bands for application by suitable means , ,~,, , -- -:: ' , ....
~2~88'~3 in the transmission. A transverse raised ridge 2~ is formed in the anchor portion at the forward edges 29 of the pockets 26 to provide contact with the anchorage rods or struts (not shown) in the transmission. The edge 2g of one pocket may be positioned slightly forward of the edge of the opposite pocket to compensate for drum deflection and improve fatigue life~
The apply portion 18 is secured to the free end 31 of the central band 13 opposite to end 22 and has an upwardly bent or folded ear or lip 32 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 33 and an integral side bumper 34 to aid in orientation of the band to the strut.
The one-piece anchor bracket member 14 is formed into an arcuate member of substantially the same curva-ture as the curved band and secured to the ends thereof as above noted~ The assembled unit is heat treated, formed and heat set to the desired diameter over an expanding fixture. The preslotted friction lining 15 having longitudinally extending slots and transverse ties is bonded to the interior surface of the formed band by a suitable adhesive, the ties 19 joining the bracket portions are cut out, and then the ties joining the bands of the strap and lining a~e removed by punch-ing or other suitable operation to form the intercon-nected three parallel bands of the final assembly 10.
;, , .. ~
:
'' ' " ~ ~`'' : , ' : . .
~8883 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, and allows 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, a radius for the corners of the anchor pockets improves band fatigue life, and the reaction or anchor pockets are coined to minimize brinnelling in use. Also, the anchor pocket contact height of edges 29 is optimized to improve fatigue life while maintaining reaction pin contact, and shot peening of the various junction points acts to improve fatigue life. Although shown with a double wrap band having parallel band portions, the bracket of the present invention could also be used in combination with a band having band portions that are tapered through a portion of their length as shown in the copending commonly assigned Canadian Patent Application Serial No. 489,883 of September 3, 198~.
... . . .
-
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 hy-draulic 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 ends of the strap to provide the apply and anchor bracket portions and a transverse tié for the band; the apply and anchor 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 lining applied thereto,~openings are pierced in the lining, the interior surface is bored and the lining is grooved, and two circumferential slots are sawed :, : ~
:
~248~383 through the lining strap and bracket except for the transverse tie to result in the three generally parallel radially expansible bands.
In commonly assigned Canadian Patent No. 1,182,379 of February 12, 1985, 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. ~ 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 assembly for a double wrap brake band which is formed from a stamped one-piece bracket member; the band and bracket being secured together and subsequently separated into the bracket portions snd three parallel bands.
The bracket assembly includes a central ~ransverse bar portion, an anchor portion and an apply portion; the anchor portion having a central raised bridging portion joining outer flanges with~anchor pocket~ formed in the side edges of the flanges to ~ 2 '`~ ~.`'. :
; :
`
receive the anchor members of the transmission. The apply portion has an upwardly folded apply ear to receive the end of a hydraulic piston or rod and an integral side bumper to aid in band orientation.
Further objects are to provide a construction of maximum simplicity, efficiency, economy, and ease of assembly, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.
Figure 1 is a partial side elevational view of the double wrap brake band and bracket assembly.
Figure 2 is a top elevational view of the finished band and bracket assembly.
Figure 3 is a top elevational view of the bracket assembly before removal of the connecting ties Figure 4 is a partial cross sectional view of the bracket taken on line 4-4 of Figure 3.
Figure 5 is a cross sectional view of the bracket taken on the line 5-5 of Figure 3.
Referring more particu~arly to the disclosure in the drawings wherein is shown an illustrative embodiment of the present invention, Figures 1 and 2 disclose a double wrap brake band and bracket assembly 10 formed of outer bands 11 and 12 and a central band 13 of substan-tially equal widths joined by a bracket assembly 14, :
;' '' : , ~ ~, ~2~ 83 shown in Figures 3 through 5. The double wrap band is formed from a preslotted stamped strap having longitu-dinally spaced ties that are removed to provide the parallel separate bands, and a preslotted friction lining 15 is applied to the strap and bracket assembly and has transverse removable ties.
The stamped one~piece anchor bracket 14 is utilized to join the opposite ends of the strap to form a circu-lar brake band 10. The bracket includes a central transverse bar portion 16 of a width equal to the strap width, an anchor portion 17 of the same width as the bar portion, and a centrally located apply portion 18; the apply portion and anchor portion being joined to the bar portion by longitudinally extending ties 19. The transverse bar portion 16 has a staggered cross over section 20 and is suitably secured, as by spot welding or brazing, to the ends 21,21 of the outer bands 11,12 and the opposite end 22 of the central band 13. The staggered cross over section 20 allows extension of the apply nose of portion 18 while maintaining the desired locked-up gap.
The anchor portion 17 is secured to the ends 23,23 of the outer bands and has a raised bridging portion 24 joining the outer flanges 25,25 and receiving thereunder the central band 13 adjacent the end 22 secured to the transverse bar portion; the bridging portion allowing for movement of the central band when the double wrap band is applied to the clutch drum or opened. ~lso, the anchor portion is provided with substantially U-shaped anchor pockets 26 which extend inwardly from the outer edges 27 of flanges 25 of the portion and are aligned with the outer bands for application by suitable means , ,~,, , -- -:: ' , ....
~2~88'~3 in the transmission. A transverse raised ridge 2~ is formed in the anchor portion at the forward edges 29 of the pockets 26 to provide contact with the anchorage rods or struts (not shown) in the transmission. The edge 2g of one pocket may be positioned slightly forward of the edge of the opposite pocket to compensate for drum deflection and improve fatigue life~
The apply portion 18 is secured to the free end 31 of the central band 13 opposite to end 22 and has an upwardly bent or folded ear or lip 32 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 33 and an integral side bumper 34 to aid in orientation of the band to the strut.
The one-piece anchor bracket member 14 is formed into an arcuate member of substantially the same curva-ture as the curved band and secured to the ends thereof as above noted~ The assembled unit is heat treated, formed and heat set to the desired diameter over an expanding fixture. The preslotted friction lining 15 having longitudinally extending slots and transverse ties is bonded to the interior surface of the formed band by a suitable adhesive, the ties 19 joining the bracket portions are cut out, and then the ties joining the bands of the strap and lining a~e removed by punch-ing or other suitable operation to form the intercon-nected three parallel bands of the final assembly 10.
;, , .. ~
:
'' ' " ~ ~`'' : , ' : . .
~8883 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, and allows 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, a radius for the corners of the anchor pockets improves band fatigue life, and the reaction or anchor pockets are coined to minimize brinnelling in use. Also, the anchor pocket contact height of edges 29 is optimized to improve fatigue life while maintaining reaction pin contact, and shot peening of the various junction points acts to improve fatigue life. Although shown with a double wrap band having parallel band portions, the bracket of the present invention could also be used in combination with a band having band portions that are tapered through a portion of their length as shown in the copending commonly assigned Canadian Patent Application Serial No. 489,883 of September 3, 198~.
... . . .
-
Claims (7)
1. A bracket assembly for use on a double wrap brake band having three substantially 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 free end of the central band, said anchor portion having a pair of oppositely opening anchor pockets in the opposite edges thereof for recep-tion of anchoring struts.
2. A bracket assembly as set forth in Claim 1, in which said anchor portion has a transverse raised rib at the forward edges of said pockets.
3. A bracket assembly as set forth in Claim 1, in which said anchor pockets have forward edges which are slightly longitudinally offset.
4. A bracket assembly as set forth in Claim 1, in which said anchor portion has a central raised bridging portion separating side flanges, and said pockets are formed in the flanges.
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 a forwardly extending integral side bumper extending from the bent lip.
7. A bracket assembly as set forth in Claim 1, wherein said transverse bar portion is staggered to allow extension of the apply nose and still meet locked gap requirements.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64757484A | 1984-09-06 | 1984-09-06 | |
| US647,574 | 1991-01-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248883A true CA1248883A (en) | 1989-01-17 |
Family
ID=24597480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000489881A Expired CA1248883A (en) | 1984-09-06 | 1985-09-03 | Bracket assembly for a double wrap band |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1248883A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5083642A (en) * | 1990-01-25 | 1992-01-28 | Advanced Friction Materials Company | Double wrap friction brake band and method of manufacture |
| CN114193750A (en) * | 2021-12-02 | 2022-03-18 | 浙江荣泰电工器材股份有限公司 | Forming device of power transmission and transformation mica pipe |
-
1985
- 1985-09-03 CA CA000489881A patent/CA1248883A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5083642A (en) * | 1990-01-25 | 1992-01-28 | Advanced Friction Materials Company | Double wrap friction brake band and method of manufacture |
| CN114193750A (en) * | 2021-12-02 | 2022-03-18 | 浙江荣泰电工器材股份有限公司 | Forming device of power transmission and transformation mica pipe |
| CN114193750B (en) * | 2021-12-02 | 2023-05-16 | 浙江荣泰电工器材股份有限公司 | Forming device of power transmission and transformation mica tube |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |