POWER SHIFT

• US 3,802,293 A
• Filed: 08/28/1972
• Issued: 04/09/1974
• Est. Priority Date: 08/28/1972
• Status: Expired due to Term

• Current Assignee: Elmer A. Richards, Peter S. Winckler
• Original Assignee: Elmer A. Richards, Peter S. Winckler
• Inventors: Richards, Elmer A., Winckler, Peter S.
• Primary Examiner(s): McKeon, Arthur T.
• Application Number:
  US05/284,163
• Time in Patent Office: 589 Days
• Field of Search: 74/331,745
• US Class Current: 74/745
• CPC Class Codes: F16H 2003/0818 comprising means for power-shifting
• CPC Class Codes: F16H 2037/045 comprising a separate gearing unit for shifting between high and low ratio range
• CPC Class Codes: F16H 2200/0052 the gear ratios comprising six forward speeds
• CPC Class Codes: F16H 3/097 the input and output shafts being aligned on the same axis
• CPC Class Codes: Y10T 74/19167 In series plural interchangeably locked nonplanetary units
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts

Abstract

A ratio shifting means including positive drive means operable during a shifting operation. The ratio shifting means is adapted particularly for automotive use and includes means for bypassing a shift location to provide positive drive means around the ratio gears for effecting a continuous and positive mechanical connection between the input and output of a transmission system during a ratio shifting operation.

Claims

1. In a range shifting transmission including a first shiftable transmission unit having ratio means defining a series of steps and a second shiftable transmission unit serially connected to said first unit and having ratio means defining at least one step which is substantially equal to the spacing between said series of steps in said first unit, the combination comprising:

bypass means including releasable power transmitting means spanning said second unit and at least said series of steps of said first unit;

means effecting power transmission by said power transmitting means when said second unit is in a neutral position and discontinuing such power transmission through said power transmitting means when said second unit is in a driving position;

whereby a positive flow of power can be obtained through said transmission during the shifting sequence of said second unit.

2. a plurality of countershafts arranged around said input shaft and selectably clutchable thereto at different ratios, each of said countershafts driving one of a plurality of coaxially mounted output gears;

b. a range shift unit serially connected with said main unit and including

3. In a transmission system, the combination comprising:

a first shiftable gear group having a plurality of progressively selectable gear ratios;

a second gear group serially connected to said first gear group and having at least two selectable ratios, the spacing of said two ratios being substantially similar to the step between a selected first and a selected second of the gear ratios in the said first gear group;

control means for range shifting said second gear group on the attainment of said second selected ratio in the shift progression of said first gear group and substantially simultaneously shifting said first gear group from said second selected ratio to said first selected ratio in said shift progression;

a bypass device including power stop means connecting the gears of said second selected ratio in said first gear group with the output of said second gear group; and

means effecting transmission of poweR through said power stop means when the power flow through said second gear group is interrupted and discontinuing transmission of power through said power stop means during conditions of power flow through said second gear group;

whereby a positive flow of power may be obtained through said transmission during a condition of simultaneous shifting of said second gear group and said selected gear ratios in said first gear group.

4. A transmission system according to claim 3, wherein said second selected ratio in said first gear group is the highest speed ratio therein.

5. A transmission system according to claim 3, wherein said bypass device is driven from the input of said first gear group and independent of any of the ratios therein.

6. A transmission system according to claim 3, including ratio means in said bypass device to cause the two sides of said power stop means to be driven at substantially synchronous rates of speed when the shiftable portions of said second gear group are running at substantially synchronous rates of speed.

7. A transmission system according to claim 3, wherein the power stop means comprises jaw clutch means.

8. A transmission system according to claim 3, wherein said power stop means is a jaw clutch having teeth whose respective surfaces on the driving sides thereof are perpendicular to the direction of rotation and whose teeth surfaces on the opposite sides thereof are at a non-perpendicular angle to said direction of rotation;

and said bypass device including ratio means so related to the ratio of said second selected ratio that the side of the power stop means connected to the transmission output will, when said second gear group is at least substantially synchronized, be driven at a rotational speed slightly faster than the side of said power stop means connected to the input of said transmission;

whereby opening of the power train through the second gear group will permit a momentary slowing of the transmission output relative to the transmission input and initial ratcheting of said jaw clutch followed by positive engagement thereof.

9. The device of claim 3 wherein the power stop means is a friction clutch.

10. A transmission system according to claim 3, wherein said second selected ratio in said first gear group is the highest speed ratio therein;

and wherein said bypass device is driven at its one end from the input of said first gear group and is connected at its other end to the output of said second gear group.

11. A transmission system according to claim 10, wherein the ratio between the lowest and highest speeds of the first gear group is slightly less than the speed ratio between the driven side of said power stop means and the output of said second gear group.

12. In a transmission system, the combination comprising:

a. a multi-speed main transmission unit providing a plurality of progressively selectable gear ratios and including

13. In a transmission having a main transmission unit and a range shift unit connected in series, the main transmission unit having a plurality of different ratio power paths each containing ratio gears, the range unit also having first and second power paths each having a different speed ratio, said range shift unit also having shiftable clutch means alternately engageable with either the first or second power path, and input and output shafts having said main transmission unit and said range unit drivingly connected in series therebetween, comprising the improvement wherein a power transmitting bypass means is automatically connectible between said input and output shafts substantially when said clutch means of said range unit is in a neutral disengaged position whereby said bypass means results in continued power transmission between said input and output shafts during shifting of said range unit, said bypass means including releasable torque transmitting means which is automatically released to discontinue the power flow through said bypass means substantially when said clutch means of said range unit is engaged with one of said first and second power paths.

14. A transmission according to claim 13, wherein said plurality of power paths in said main transmission unit includes a first power path having the greatest speed ratio thereacross and a second power path having the smallest speed ratio thereacross, the difference in the speed ratios between said first and second power paths in said main transmission unit being substantially equal to the difference in the speed ratios between said first and second power paths in said range unit.

15. A transmission according to claim 13, wherein each of the power paths in said main transmission unit also has releasable clutch means associated therewith, and said bypass means bypassing both the clutch means in said range unit and the clutch means in said main transmission unit for permitting continued power transmission between the input and output shafts when shifting is simultaneously being performed in both the main and range transmission units.

16. In a range shifting transmission, the combination including:

a plurality of substantially parallel shafts including an input shaft, an intermediate shaft and an output shaft, said input shaft being drivingly connected to an engine of a vehicle;

a main transmission unit shiftable through a series of steps and drivingly connected between said intermediate shaft and one of said input and output shafts, said main transmission unit including a plurality of interruptable power paths between said one shaft and said intermediate shaft with said plurality of power paths being of different ratios;

a second transmission unit shiftable through at least one step and drivingly connected between said intermediate shaft and the other of said input and output shafts, said second transmission unit including at least two interruptable power paths of substantially different ratios connected between said intermediate shaft and said other shaft;

said second transmission unit including shift means associated therewith for shifting of said second transmission unit between said two power paths only when said first transmission unit is being shifted out of or into its highest ratio power path during upshifting and downshifting of the transmission, respectively;

an interruptable bypass system drivingly disposed in parallel with said second transmission unit and at least a portion of said first transmission unit for permitting substantially continuous flow of power from said input shaft to said output shaft during shifting of said second transmission unit, said bypass system including an interruptable power transmitting means; and

means for effecting power transmission by said power transmitting means during shifting of said second transmission unit and for discontinuing power transmission by said poWer transmission means when said second unit is in a driving position.

17. A transmission according to claim 16, wherein the power paths associated with one of said first and second transmission units includes gear means drivingly connected to and continuously rotated with said input shaft whenever said input shaft is rotated.

18. In a range shift transmission connectible between input and output shafts and including a first shiftable transmission unit drivingly connected to one of said shafts and a second shiftable transmission unit serially connected between said first unit and said other shaft;

said first unit including means defining a plurality of interruptable power paths each providing a different speed ratio between the input and output of said first unit, and shifting means associated with said power paths for permitting a selected one of said power paths to be used for transmitting power through said first transmission unit, said shifting means in association with said power paths causing said first transmission unit to have a series of progressive shifting steps;

said first transmission unit further including a gear fixed to and rotatable with said one shaft, and a plurality of countershafts parallel with said one shaft and each having a further gear associated therewith and disposed in continuous meshing engagement with said first-mentioned gear, said further gears being associated with said power paths whereby at least a portion of said power paths is rotated whenever said one shaft rotates;

said second transmission unit including at least two interruptable power paths for drivingly interconnecting said other shaft and said first transmission unit, said two power paths each having ratio means associated therewith but of different ratios so as to define a shifting step therebetween, the ratio difference associated with the shifting step of said second transmission unit being substantially greater than the ratio difference associated with any individual shifting step of said first transmission unit; and

an interruptable bypass system disposed in parallel with said first and second transmission units and drivingly connectible between said input and output shafts for effecting substantially continuous flow of power between said shafts during shifting of said second transmission unit, said bypass system including a releasable power transmitting means associated therewith and capable of transmitting power therethrough whenever said second transmission unit is shifted.