Automatic transmission with anti creep device

• US 4,686,872 A
• Filed: 09/13/1984
• Issued: 08/18/1987
• Est. Priority Date: 09/20/1983
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Aoki, Takashi, Sato, Yoichi, Fukuda, Yukihiro
• Primary Examiner(s): Herrmann, Allan D.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/650,359
• Time in Patent Office: 1,069 Days
• Field of Search: 74/869, 74/867, 74/868, 74/878, 74/866, 74/877, 192/0.076, 192/3.57
• US Class Current: 477/114
• CPC Class Codes: F16H 61/0267 Layout of hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/30
• CPC Class Codes: F16H 61/20 Preventing gear creeping ; Transmission control during standstill, e.g. hill hold control
• CPC Class Codes: F16H 61/684 without interruption of drive

Abstract

An automatic transmission includes a mechanical transmission mechanism coupled to a fluid coupling. The mechanical transmission mechanism has several power trains and several friction engagement mechanisms. By selective supply of actuating fluid pressure to selective ones of the friction engagement mechanisms, various speed stages are provided. A control system for this transmission includes a mechanism for producing a signal representative of engine output and an anti creep device for varying the actuating hydraulic fluid pressure for one of the friction engagement mechanisms which is engaged for providing the lowest speed stage, according to the signal representative of engine output, from a low value when engine output is low upward as engine output increases. The anti creep device may include a hydraulic fluid chamber whose volume alters during alteration of amount of applying of anti creep action, and a fluid conduit system for connecting this hydraulic fluid chamber to the outside with a flow resistance which is different in the outwards direction and the inwards direction. Alternatively, the anti creep device may vary the actuating hydraulic fluid pressure for that one of the friction engagement mechanisms, according to the signal representative of engine output, upward from a low value when the signal is low, as the signal increases, substantially in proportion to the signal, up to a certain value of the signal; and may then set, for values of the signal greater than the certain value, the actuating hydraulic fluid pressure substantially equal to a certain maximum value.

Claims

1. An automatic transmission, comprising:

(a) a fluid coupling;

(b) a mechanical transmission mechanism coupled to said fluid coupling, comprising a plurality of power trains and a plurality of friction engagement mechanisms, various ones of said power trains being selectively engageable according to selective supply of actuating fluid pressure to selective ones of said friction engagement mechanisms to provide various speed stages including a lowest speed stage; and

(c) a transmission control system comprising;

(d) means for producing a signal representative of engine output; and

(e) anti creep means for varying the actuating hydraulic fluid pressure for a one of said friction engagement mechanisms which is engaged for providing said lowest speed stage, according to said signal representative of engine output, from a low value when engine output is low upward as engine output increases;

(f) said anti creep means comprising a hydraulic fluid chamber whose volume alters in relation to the amount of anti-creep action, and means for communicating said hydraulic fluid chamber to a fluid conduit system, said fluid conduit system having a flow resistance which is different in magnitude when said hydraulic fluid chamber is venting from when said hydraulic fluid chamber if filling; and

(g) said hydraulic fluid chamber decreasing in volume as said anti creep means applies less anti creep action, and said means for communicating said hydraulic fluid chamber to said fluid conduit system provides a flow resistance which is less in magnitude for flow venting said hydraulic fluid chamber than for flow filling said hydraulic fluid chamber.

2. An automatic transmission according to claim 1, wherein said means for communicating said hydraulic fluid chamber to said fluid conduit system includes a one-way valve and a throttling element connected in parallel, said one-way valve permitting flow out from said hydraulic fluid chamber and preventing flow into said hydraulic fluid chamber.

3. An automatic transmission, comprising:

(a) a fluid coupling;

(b) a mechanical transmission mechanism coupled to said fluid coupling, comprising a plurality of power trains and a plurality of friction engagement mechanisms, various ones of said power trains being selectively engageable according to selective supply of actuating fluid pressure to selective ones of said friction engagement mechanisms to provide various speed stages including a lowest speed stage; and

(c) a transmission control system comprising;

(d) means for producing a signal representative of engine output; and

(e) anti creep means for varying the actuating hydraulic fluid pressure for a one of said friction engagement mechanism which is engaged for providing said lowest speed stage, according to said signal representative of engine output, from a low value when engine output is low upward as engine output increases;

(f) said anti creep means comprising a hydraulic fluid chamber whose volume alters in relation to the amount of anti creep action, and means for communicating said hydraulic fluid chamber to a fluid conduit system, said fluid conduit system having a flow resistance which is different in magnitude when said hydraulic fluid chamber is venting from when said hydraulic fluid chamber is filling;

(g) said hydraulic fluid chamber increasing in volume as said anti creep means applied more anti creep action, and said means for communicating said hydraulic fluid chamber to said fluid conduit system provides a flow resistance which is greater in magnitude for flow venting said hydraulic fluid chamber than for flow filling said hydraulic fluid chamber.

4. An automatic transmission according to claim 3, wherein said means for communicating said hydraulic fluid chamber to said fluid conduit system includes a one-way valve and a throttling element connected in parallel, said one-way valve permitting flow into said hydraulic fluid chamber and preventing flow out from said hydraulic fluid chamber.

5. An automatic transmission, comprising:

(a) a fluid coupling;

(b) a mechanical transmission mechanism coupled to said fluid coupling, comprising a plurality of power trains and a plurality of friction engagement mechanisms, various ones of said power trains being selectively engageable according to selective supply of actuating fluid pressure to selective ones of said friction engagement mechanisms to provide various speed stages including a lowest speed stage; and

(c) a transmission control system comprising;

(d) means for producing a signal representative of engine output; and

(e) an anti creep means for varying the actuating hydraulic fluid pressure for a one of said friction engagement mechanisms which is engaged for providing said lowest speed stage, according to said signal representative of engine output, from a low value when engine output is low upward as engine output increases;

(f) said anti creep means comprising;

(g) an anti creep valve having at least a first pressure chamber and a second pressure chamber,

(h) an override valve having at least a first pressure chamber and a second pressure chamber,

(i) anti creep valve means for communicating hydraulic fluid pressure from said one of said friction engagement mechanisms to said override valve,

(j) override valve means for communicating the hydraulic fluid pressure from said one of said fluid engagement mechanisms to said anti creep valve, said communicating means integral with said override valve operative to selectively permit anti creep action,

(k) a fluid conduit system providing communication between said first pressure chamber of said anti creep valve and said second pressure chamber of said override valve for substantially terminating anti creep action when said engine output is at a predetermined level,

(l) means for varying the rate of application of anti creep action, and

(m) said varying means comprising a throttle means and one-way valve means communicating with said anti creep valve for rapidly terminating anti creep action when said engine output is at a predetermined level and slowly restoring anti creep action when said engine output is below said predetermined level.

6. An automatic transmission, comprising:

(a) a fluid coupling;

(b) a mechanical transmission mechanism coupled to said fluid coupling, comprising a plurality of power trains and a plurality of friction engagement mechanisms, various ones of said power trains being selectively engageable according to selective supply of actuating fluid pressure to selective ones of said friction engagement mechanisms to provide various speed stages including a lowest speed stage; and

(c) a transmission control system comprising;

(d) means for producing a signal representative of engine output; and

(e) an anti creep means for varying the actuating hydraulic fluid pressure for a one of said friction engagement mechanisms which is engaged for providing said lowest speed stage, according to said signal representative of engine output, from a low value when engine output is low upward as engine output increases;

(f) said anti creep means comprising;

(g) an anti creep valve having at least a first pressure chamber and a second pressure chamber,

(h) an override valve having at least a first pressure chamber and a second pressure chamber,

(i) anti creep valve means for communicating hydraulic fluid pressure from said one of said friction engagement mechanisms to said override valve,

(j) override valve means for communicating the hydraulic fluid pressure from said one of said fluid engagement mechanisms to said anti creep valve, said communicating means integral with said override valve operative to selectively permit anti creep action,

(k) a fluid conduit system providing communication between said first pressure chamber of said anti creep valve and said second pressure chamber of said override valve for substantially terminating anti creep action when said engine output is at a predetermined level,

(l) means for varying the rate of application of anti creep action, and

(m) said varying means comprising a throttle means and one-way valve means communicating with said override valve for rapidly terminating anti creep action when said engine output is at a predetermined level and slowly restoring anti creep action when said engine output is below said predetermined level.