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Title:
POSITION ACTUATOR
Document Type and Number:
WIPO Patent Application WO/2018/025071
Kind Code:
A1
Abstract:
A position actuator includes a cylinder housing forming a fluid chamber having a first portion and a second portion, a movable main piston disposed in the second portion, a piston rod firmly attached to the main piston and extending through one end of the cylinder housing, and a push ring disposed in the first portion and axially movable relative to the main piston. The position actuator also includes a first port extending through the cylinder housing to allow fluid to communicate with the first portion between the main piston and the one end of the cylinder housing and a second port extending through the cylinder housing to allow fluid to communicate with the second portion between the main piston and another end of the cylinder housing, wherein at least one of the first portion and the second portion are pressurized to move the main piston to at least one of a first position and a second position.

Inventors:
LJØSNE, Knut Tore (Toppåsveien 71, 1262 Oslo, 1262, NO)
VESTGÅRD, Bård (Parkveien 10, 3413 Lier, 3413, NO)
BJØRKGÅRD, Sven (Rådmann Friis vei 41, 3610 Kongsberg, 3610, NO)
Application Number:
IB2016/054755
Publication Date:
February 08, 2018
Filing Date:
August 05, 2016
Export Citation:
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Assignee:
KONGSBERG AUTOMOTIVE AS (Dyrmyrgata 48, P.O. Box 62, 3601 Kongsberg, 3601, NO)
International Classes:
F15B11/12; F16H61/30
Domestic Patent References:
WO2012123181A12012-09-20
WO2007064221A12007-06-07
Foreign References:
US4773300A1988-09-27
US20030136254A12003-07-24
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A position actuator comprising:

a cylinder housing forming a fluid chamber having a first portion and a second portion; a movable main piston disposed in said second portion;

a piston rod firmly attached to said main piston and extending through one end of said cylinder housing;

a push ring disposed in said first portion and axially movable relative to said main piston; a first port extending through said cylinder housing to allow fluid to communicate with said first portion between said main piston and the one end of said cylinder housing; and

a second port extending through said cylinder housing to allow fluid to communicate with said second portion between said main piston and another end of said cylinder housing, wherein at least one of said first portion and said second portion are pressurized to move said main piston to at least one of a first position and a second position.

2. A position actuator as set forth in claim 1 wherein said second portion has a diameter larger than a diameter of said first portion.

3. A position actuator as set forth in claim 1 wherein said first port extends radially inward into said cylinder housing on one side of said main piston to receive pressurized air.

4. A position actuator as set forth in claim 3 wherein said second port extends radially inward into said cylinder housing on another side of said main piston to receive pressurized air.

5. A position actuator as set forth in claim 4 including a third port disposed axially between said first port and said second port and extending radially inward into said cylinder housing to vent air to atmosphere.

6. A position actuator as set forth in claim 5 including a secondary piston disposed in said second chamber of said housing between said main piston and another end of said cylinder housing.

7. A position actuator as set forth in claim 6 including a coupling member disposed axially between said main piston and said secondary piston and coupling said secondary piston to said piston rod to allow said secondary piston to move within stroke boundaries defined by said coupling member.

8. A position actuator as set forth in claim 6 wherein said housing includes a fourth port communicating with said second chamber to vent air to atmosphere.

9 A position actuator as set forth in claim 1 wherein said main piston has a first diameter.

10. A position actuator as set forth in claim 9 wherein said main piston has a reduced diameter portion of a second diameter less than said first diameter.

1 1 A position actuator as set forth in claim 1 wherein said cylinder housing has a step formed between said first portion and said second portion to stop axial movement of said push ring.

12. A position actuator as set forth in claim 1 wherein said push ring forms a floating piston.

13. A position actuator comprising:

a cylinder housing forming a fluid chamber having a first portion and a second portion, wherein said second portion has a diameter larger than said first portion;

a movable main piston disposed in said second portion;

a piston rod firmly attached to said main piston and extending through one end of said cylinder housing;

a push ring forming a floating piston disposed in said first portion and axially movable relative to said main piston;

a first port extending through said cylinder housing to allow fluid to communicate with said first portion between said main piston and the one end of said cylinder housing;

a second port extending through said cylinder housing to allow fluid to communicate with said second portion between said main piston and another end of said cylinder housing, wherein at least one of said first portion and said second portion are pressurized to move said main piston to at least one of a first position and a second position; and

wherein said cylinder housing has a step formed between said first portion and said second portion to stop axial movement of said push ring.

14. A position actuator as set forth in claim 13 wherein said first port extends radially inward into said cylinder housing on one side of said main piston to receive pressurized air.

15. A position actuator as set forth in claim 14 wherein said second port extends radially inward into said cylinder housing on another side of said main piston to receive pressurized air.

16. A position actuator as set forth in claim 15 including a third port disposed axially between said first port and said second port and extending radially inward into said cylinder housing to vent air to atmosphere.

17. A position actuator as set forth in claim 16 wherein said housing includes a fourth port communicating with said second chamber to vent air to atmosphere.

18. A position actuator comprising:

a cylinder housing forming a fluid chamber having a first portion and a second portion, wherein said second portion has a diameter larger than said first portion; a movable main piston disposed in said second portion, wherein said main piston has a first diameter and a reduced diameter portion of a second diameter less than said first diameter; a piston rod firmly attached to said main piston and extending through one end of said cylinder housing;

a push ring forming a floating piston disposed in said first portion and axially movable relative to said main piston;

a first port extending radially inward into said cylinder housing on one side of said main piston to allow pressurized fluid to communicate with said first portion between said main piston and the one end of said cylinder housing;

a second port extending radially inward into said cylinder housing on another side of said main piston to allow pressurized fluid to communicate with said second portion between said main piston and another end of said cylinder housing;

a third port disposed axially between said first port and said second port and extending radially inward into said cylinder housing to vent air to atmosphere;

a fourth port communicating with said second chamber to vent air to atmosphere;

wherein at least one of said first portion and said second portion are pressurized to move said main piston to at least one of a first position and a second position; and

wherein said cylinder housing has a step formed between said first portion and said second portion to stop axial movement of said push ring.

19. A position actuator as set forth in claim 18 including a secondary piston disposed in said second chamber of said housing between said main piston and the another end of said cylinder housing.

20. A position actuator as set forth in claim 19 including a coupling member disposed axially between said main piston and said secondary piston and coupling said secondary piston to said piston rod to allow said secondary piston to move within stroke boundaries defined by said coupling member.

21. A transmission unit comprising:

at least one shift rail for actuating at least one gear;

at least one actuator cooperating with the at least one shift rail; and

said at least one actuator comprising a cylinder housing forming a fluid chamber having a first portion and a second portion, a movable main piston disposed in said second portion, a piston rod firmly attached to said main piston and extending through one end of said cylinder housing, a push ring disposed in said first portion and axially movable relative to said main piston, a first port extending through said cylinder housing to allow fluid to communicate with said first portion between said main piston and the one end of said cylinder housing, and a second port extending through said cylinder housing to allow fluid to communicate with said second portion between said main piston and another end of said cylinder housing, wherein at least one of said first portion and said second portion are pressurized to move said main piston to at least one of a first position and a second position.

22. A transmission as set forth in claim 21 wherein said first port extends radially inward into said cylinder housing on one side of said main piston to receive pressurized air.

23. A transmission as set forth in claim 22 wherein said second port extends radially inward into said cylinder housing on another side of said main piston to receive pressurized air.

24. A transmission as set forth in claim 23 including a third port disposed axially between said first port and said second port and extending radially inward into said cylinder housing to vent air to atmosphere.

25. A transmission as set forth in claim 24 wherein said housing includes a fourth port communicating with said second chamber to vent air to atmosphere.

26. A transmission as set forth in claim 25 including a secondary piston disposed in said second chamber of said housing between said main piston and the another end of said cylinder housing.

27. A transmission as set forth in claim 26 including a coupling member disposed axially between said main piston and said secondary piston and coupling said secondary piston to said piston rod to allow said secondary piston to move within stroke boundaries defined by said coupling member.

Description:
POSITION ACTUATOR

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates generally to position actuators for powertrains and, more particularly, to a position actuator for a powertrain of a vehicle.

2. Description of the Related Art

[0002] It is known to provide a pneumatically actuated position actuator for actuating components in a powertrain such as gears and clutches in a transmission. An example of such a positon actuator is disclosed in U.S. Patent Application Publication No. 2003/0136254 to Hirano et al. In this patent publication, the positon actuator includes a housing, a movable internal piston disposed in a chamber within the housing, and a piston rod extending axially from the piston through one end of the housing. For such a position actuator, a partition wall divides a housing into two pressure chambers. In addition, the position actuator has a lower force from an end position to a middle position thereof, which is not favorable if used as a gear shift actuator where it is desired to have the highest force out of gear, not into gear.

[0003] As such, it is desirable to provide a position actuator with a minimum number of parts and a minimum build length. In addition, it is desirable to provide a position actuator to disengage one gear and stop the position actuator in a neutral position afterwards. Normally, for stopping in a neutral position, both sides of the piston are pressurized. Some manufactures use relatively large actuators or a quick regulator system to make sure there is enough force available into neutral, with both sides fully pressurized. However, the force is not high enough if both sides of the actuator are fully pressurized.

SUMMARY OF THE INVENTION

[0004] Accordingly, the present invention provides a position actuator with a minimum number of parts and a minimum build length.

[0005] In one embodiment, the present invention provides a position actuator including a cylinder housing forming a fluid chamber having a first portion and a second portion, a movable main piston disposed in the second portion, a piston rod firmly attached to the main piston and extending through one end of the cylinder housing, and a push ring disposed in the first portion and axially movable relative to the main piston. The position actuator also includes a first port extending through the cylinder housing to allow fluid to communicate with the first portion between the main piston and the one end of the cylinder housing and a second port extending through the cylinder housing to allow fluid to communicate with the second portion between the main piston and another end of the cylinder housing. At least one of the first portion and the second portion are pressurized to move the main piston to at least one of a first position and a second position.

[0006] One advantage of the present invention is that a new position actuator is provided that does not need two pressure chambers with a partition wall therebetween, saving space, cost, and making assembly easier. Another advantage of the present invention is that the position actuator is a more compact actuator with distinct positions, with comparatively high force against the middle position (from both sides). Yet another advantage of the present invention is that the position actuator has diameters to provide a higher force going from each end positon towards the middle position, compared to from the middle position to the end positons, or at least the same force.

[0007] Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a position actuator, according to one embodiment of the present invention, illustrated in operational relationship with a portion of a powertrain.

[0009] FIG. 2 is an enlarged fragmentary elevational view of the position actuator of FIG. 1 illustrated in a first operational position.

[0010] FIG. 3 is a view similar to FIG. 2 illustrating the position actuator of FIG.

1 illustrated in a second operational position.

[0011] FIG. 4 is a view similar to FIG. 2 illustrating the position actuator of FIG.

1 illustrated in a third operational position.

DESCRIPTION OF THE PREFERRED EMBODIMENT'S)

[0012] As disclosed in FIGS. 1 through 4, one embodiment of a position actuator

10, according to the present invention, is shown as a pneumatic actuator for moving components of a vehicle powertrain (not shown) such as gears and clutches in an automized transmission or an automatic manual transmission. In the embodiment illustrated in FIG. 1 , the position actuator 10 is used to move a shift rail 11 to engage and disengage at least one gear in the transmission. It should be appreciated that the positon actuator 10 may be used in other embodiments for the vehicle other than the powertrain. It should also be appreciated that the position actuator 10 may be a two-position actuator or a three-position actuator.

[0013] Referring to FIGS. 2-4, the positon actuator 10 includes a cylinder housing

12 extending axially. The cylinder housing 12 is generally cylindrical in shape with a generally circular cross-section. The cylinder housing 12 has a wall 14 forming a fluid chamber 16 therein. The chamber 16 has a first portion 18, a second portion 20, and a third portion 21. The first portion 18 has a diameter greater than a diameter of the second portion 20 and the second portion 20 has a diameter greater than a diameter of the third portion 21. The cylinder housing 12 also extends axially between a first end 22 and a second end 24 and has a first shoulder or step 26 disposed axially between the first portion 18 and the second portion 20 to form an axial stop for a push ring 52 to be described and a second shoulder or step 27 disposed axially between the second portion 20 and the third portion 21 to form an axial stop for a main piston 30 to be described. The cylinder housing 12 includes an opening or aperture 28 extending axially through the first end 22 and fluidly communicating with the first portion 18 of the chamber 16. The aperture 28 allows a piston rod 38 to be described to extend through the first end 22 of the cylinder housing 12. It should be appreciated that the cylinder housing 12 may have any suitable shape.

[0014] The positon actuator 10 also includes a movable internal main piston 30 disposed in the second portion 20 of the chamber 16. The main piston 30 is generally cylindrical in shape. The main piston 30 has a diameter less than a diameter of the second portion 20 of the cylinder housing 12 to allow the main piston 30 to be movable axially in the second portion 20 of the chamber 16 of the cylinder housing 12. The main piston 30 includes a central aperture 32 extending axially therethrough to receive a piston rod 38 to be described. The central aperture 32 may include a reduced diameter portion 33. The main piston 30 has a reduced diameter portion 34 at one end. The reduced diameter portion 34 has a diameter less than a diameter D 2 of the main piston 30. The main piston 30 also has one or more grooves 36 extending circumferentially and radially therein and spaced axially to receive one or more seals 76 to be described. In one embodiment, the main piston 30 is integral, unitary, and one-piece. It should be appreciated that the seals 76 engage the wall 14 of the cylinder housing 12 and prevent airflow past the main piston 30.

[0015] The position actuator 10 further includes a piston rod 38 connected to and extending axially from the main piston 30 for actuation of a component such as the shift fork 11. The piston rod 38 has a first portion 40 extending axially through the aperture 28 and into the central aperture 32 and a second portion 42 extending axially from the first portion 40 and into the reduced diameter portion 33 of the central aperture 32 of the main piston 30. The first portion 40 has a first diameter Di and the second portion 42 has a second diameter less than the first diameter. In one embodiment, the piston rod 38 is integral, unitary, and one-piece. It should be appreciated that a seal is disposed in the cylinder housing 12 about the piston rod 38 and prevent airflow past the piston rod 38. It should also be appreciated that one end of the first portion 40 may be coupled to the shift rail 11 via an aperture (not shown) extending diametrically therethrough.

[0016] The position actuator 10 also includes at least one port or channel, generally indicated at 44, in the wall 14 of the cylinder housing 12. The at least one port 44 extends radially into the wall 14 of the cylinder housing 12. In one embodiment, the at least one port 44 includes a first port 46, a second port 48, a third port 50, and a fourth port 51. The first port 46 extends radially inward into the wall 14 of the cylinder housing 12 on one side of the main piston 30 to allow fluid such as air to communicate with the first portion 18 of the chamber 16 between the main piston 30 and the first end 22 of the cylinder housing 12. The second port 48 extends radially inward into the wall 14 of the cylinder housing 12 on another side of the main piston 30 to allow fluid to communicate with the second portion 20 and third portion 21 of the chamber 16 at the second step 27 of the cylinder housing 12. The third port 50 is disposed axially between the first port 46 and the second port 48 and extends radially inward into the wall 14 of the cylinder housing 12 to allow fluid to communicate with the first portion 18 and the second portion 20 of the chamber 16 at the first step 26 of the cylinder housing 12. The fourth port 51 extends radially inward into the wall 14 of the cylinder housing 12 on one side of a secondary piston 60 to be described to allow fluid such as air to communicate with the third portion 21 of the chamber 16 between the secondary piston 30 and the second end 24 of the cylinder housing 12. It should be appreciated that the port 44 may have any suitable shape. It should also be appreciated that the first and second ports 46 and 48 are working ports and the third and fourth ports 50 and 51 are venting ports. It should further be appreciated that valves (not shown) for raising and lowering the pressure of the fluid may be provided for the chamber 16.

[0017] The position actuator 10 further includes a push ring 52 disposed axially in the first portion 18 of the chamber 16 between the main piston 30 and the first end 22 of the cylinder housing 12. The push ring 52 includes a central aperture 54 extending axially therethrough to receive the reduced diameter portion 34 of the main piston 30. The push ring 52 has a reduced diameter portion 56 at one end. The reduced diameter portion 56 has a diameter less than a diameter D 3 of the push ring 52. The push ring 52 has at least one groove 58 extending circumferentially and radially therein to receive at least one seal 76 to be described. In one embodiment, the push ring 52 is integral, unitary, and one-piece. It should be appreciated that the seal 76 engages the wall 14 of the cylinder housing 12 and prevents airflow past the push ring 52. It should also be appreciated that the push ring 52 forms a floating piston and is movable axially relative to the main piston 30.

[0018] The position actuator 10 further includes a secondary or balancing piston

60 disposed axially in the third portion 21 of the chamber 16 between the main piston 30 and the second end 24 of the cylinder housing 12. The secondary piston 60 includes a central cavity 62 extending axially therein to receive a connector 70 to be described. The secondary piston 60 has a reduced diameter portion 64 at one end. The reduced diameter portion 64 has a diameter less than a diameter D 4 of the secondary piston 60. The reduced diameter portion 64 has a flange 66 at one axial end extending radially inward to engage the connector 70. The secondary piston 60 has at least one groove 68 extending circumferentially and radially therein to receive at least one seal 76 to be described. In one embodiment, the connector 70 is integral, unitary, and one-piece. It should be appreciated that the seal 76 engages the wall 14 of the cylinder housing 12 and prevents airflow past the secondary piston 60.

[0019] The position actuator 10 includes a coupling member or connector 70 disposed axially between the main piston 30 and the secondary piston 60. The connector 70 is generally cylindrical in shape and extends axially. The connector 70 has an aperture 72 extending axially therethrough to receive the second portion 42 of the piston rod 38. The connector 70 includes a flange 74 extending radially outwardly at one axial end and disposed in the central cavity 62 of the secondary piston 60 to cooperate with the flange 66 of the reduced diameter portion 64 of the secondary piston 60. It should be appreciated that the secondary piston 60 is free to move within the stroke boundaries defined by the connector 70.

[0020] The position actuator 10 also includes a seal 76 disposed in the groove 36 of the main piston 30, the groove 58 of the push ring 52, and the groove 68 of the secondary piston 60. The grooves 36, 58, and 68 are generally annular and rectangular in shape, but may have any suitable shape. The grooves 36 extend radially inwardly into a wall of the main piston 30 and the reduced diameter portion 34, the groove 58 extends radially inwardly into a wall of the push ring 52, and the groove 68 extends radially inwardly into a wall of the secondary piston 60. The seal 76 is generally annular in shape. In one embodiment, the seal 76 has a generally rectangular cross-sectional shape. The seal 76 is made of a flexible elastomeric material such as rubber. The seal 76 is integral, unitary, and one-piece. It should be appreciated that the seal 76 may be any suitable type of seal such as a lip seal, o-ring, etc.

[0021] In operation of the position actuator 10, as illustrated in FIG. 2, the main piston 30 has a first position when the main piston 30 is near the first end 22 of the cylinder housing 12 when a gear of a powertrain is engaged. When airflow enters the first port 46, the first portion 18 is pressurized. When the pressure in the first portion 18 is greater than the pressure in the second portion 20, the main piston 30 moves toward the second end 24 of the cylinder housing 12 to a middle, neutral, or third positon to cause the shift rail 11 to disengage the gear and air vents to atmosphere through the third port 50. As illustrated in FIG. 3, the main piston 30 has a second position when the main piston 30 is near the second end 24 of the cylinder housing 12 when a gear of a powertrain is engaged. When airflows enters the second port 48, the second portion 20 is pressurized. When the pressure in the second portion 20 is greater than the pressure in the first portion 18, the main piston 30 moves toward the first end 22 of the cylinder housing 12 to the third position to cause the shift rail 11 to disengage the gear and air vents to atmosphere through the third port 50. As illustrated in FIG. 4, the main piston 30 has a middle, neutral, or third position when the main piston 30 is disposed axially between the first position and the second position when the first portion 18 and the second portion 20 of the chamber 16 when a gear of a powertrain is disengaged. When airflow enters the first port 46, second port 48, and third port 50, both sides of the main piston 30 are pressurized. It should be appreciated that, when the pressure in first portion 18 equals the pressure in the second portion 20, there is no movement of the main piston 30. It should also be appreciated that, if only the side (D2) of the main piston 30 is pressurized, then the side (D4) of the secondary piston 60 will reduce the force to avoid it being too high and if both sides (D1/D3 and D2) of the main piston 30 are pressurized, the side (D4) of the secondary piston 60 will increase the force from left towards mid-position. It should further be appreciated that the three-position actuator 10 has one or more valves (not shown) for allowing fluid flow such as air into the chamber 16.

[0022] The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.

[0023] Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, the present invention may be practiced other than as specifically described.