Thermally compensated standpipe assembly for automatic transmission oil fill

• US 20040226774A1
• Filed: 05/14/2003
• Published: 11/18/2004
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Gutta, Thomas M., Gunderson, Joel H.
• Granted Patent: US 7,325,653 B2
• Time in Patent Office: Days
• US Class Current: 184/1.5
• CPC Class Codes: F01M 11/0408 Sump drainage devices, e.g. valves, plugs
• CPC Class Codes: F16H 57/0408 Exchange, draining or filling of transmission lubricant

Abstract

A standpipe assembly for installation in the fluid sump of a vehicular transmission includes a two-piece fill pipe, a drain nut, a drain plug and a thermal actuator. The fill pipe includes a first tube having a first end secured in a flow passage formed in the drain nut and a second tube having a first end fitted for bidirectional sliding movement on a second end of the first tube. The drain nut is secured within a mounting bore formed through a housing of the transmission. The drain plug is adapted for threaded retention within the flow passage of the drain nut. The thermal actuator is operable for varying the length of the fill pipe by adjusting the position of the second tube relative to the first tube in response to thermal variations.

Claims

1. A transmission for a motor vehicle, comprising:

a housing defining a sump having fluid therein and a mounting bore communicating with said sump; and

a standpipe assembly operably mounted in said mounting bore so as to extend into said sump, said standpipe assembly including a first tube defining a first flow passage, a second tube supported for sliding movement relative to said first tube and defining a second flow passage which communicates with said first flow passage, and a thermal actuator operable for varying the position of said second tube relative to said first tube in response to changes in the temperature of said fluid in said sump.

2. The transmission of claim 1 wherein said first tube has a first end secured to said housing and a second end, said second tube has a first end disposed for sliding movement on said second end of said first tube and a second end defining an inlet to said second flow passage.

3. The transmission of claim 2 wherein said thermal actuator surrounds said first tube and engages said first end of said second tube, said thermal actuator operable for moving said inlet of said second tube from a first position to a second position in response to a change in the fluid temperature in said sump increasing from a first temperature value to a second temperature value.

4. The transmission of claim 3 wherein movement of said inlet of said second tube to its second position corresponds to a higher fluid level in said sump.

5. The transmission of claim 4 wherein said thermal actuator permits movement of said inlet of said second tube from its second position to its first position when the temperature of said fluid decreases from said second temperature value to said first temperature value.

6. The transmission of claim 3 wherein said thermal actuator is a coil spring made from a material capable of varying length dimension of said coil spring in response to variations in the temperature of said fluid in said sump.

7. The transmission of claim 6 wherein said coil spring is made from a bimetallic material.

8. The transmission of claim 1 wherein said standpipe assembly further includes a threaded drain nut adapted for engagement with threads formed in said mounting bore for securing said drain nut to said housing, said first tube being secured to said drain nut with its first flow passage communicating with a drain port through said drain nut.

9. The transmission of claim 8 wherein said standpipe assembly further comprises a drain plug adapted for retention in said drain port of said drain nut to prevent fluid in said sump from draining out of said housing.

10. The transmission of claim 1 wherein said second tube has an end segment which surrounds an end segment of said first tube.

11. The transmission of claim 10 wherein said end segment of said first tube includes a radial flange having an end surface facing an inner wall surface of said second tube, and wherein said end segment of said second tube includes a radial flange having an end surface facing an outer wall surface of said first tube.

12. The transmission of claim 11 wherein said standpipe assembly further includes a biasing spring disposed between said radial flanges of said first and second tubes.

13. In a transmission for a motor vehicle having a housing defining a fluid sump and a mounting bore communicating with the sump, a standpipe assembly comprising:

a first tube mounted in the mounting bore so as to extend into the sump, said first tube defining a first flow passage;

a second tube supported for sliding movement relative to said first tube and defining a second flow passage which communicates with said first flow passage; and

a thermal actuator operable for varying the position of said second tube relative to said first tube in response to changes in the temperature of fluid in the sump.

14. The standpipe assembly of claim 13 wherein said first tube has a first end secured to the housing and a second end, said second tube has a first end disposed for sliding movement on said second end of said first tube and a second end defining an inlet to said second flow passage.

15. The standpipe assembly of claim 14 wherein said thermal actuator surrounds said first tube and engages said first end of said second tube, said thermal actuator operable for moving said inlet of said second tube from a first position to a second position in response to a change in the fluid temperature in the sump increasing from a first temperature value to a second temperature value.

16. The standpipe assembly of claim 15 wherein movement of said inlet of said second tube to its second position corresponds to a higher fluid level in said sump.

17. The standpipe assembly of claim 15 wherein said thermal actuator is a coil spring made from a material capable of varying length dimension of said coil spring in response to variations in the temperature of the fluid in the sump.

18. The standpipe assembly of claim 17 wherein said coil spring is made from a bimetallic material.

19. The standpipe assembly of claim 13 further comprising:

a threaded drain nut adapted for engagement with threads formed in the mounting bore for securing said drain nut to the housing, said first tube being secured to said drain nut with its first flow passage communicating with drain port through said drain nut; and

a drain plug adapted for retention in said drain port of said drain nut to prevent fluid from draining out of the housing.

20. The standpipe assembly of claim 13 wherein said second tube has an end segment which surrounds an end segment of said first tube, said end segment of said first tube includes a radial flange having an end surface facing an inner wall surface of said second tube, and wherein said end segment of said second tube includes a radial flange having an end surface facing an outer wall surface of said first tube.

21. The standpipe assembly of claim 20 further including a biasing spring disposed between said radial flanges of said first and second tubes.