JPH0454369Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a shift control device for an automatic transmission vehicle.

(Prior art) As a conventional auxiliary braking device, for example, there is an exhaust brake device as shown in Figure 3 (NISSAN
Service bulletin No. 449, Nitsusan Atlas Condor, page 96 (December 1981, published by Nissan Motor Co., Ltd.).
That is, a key switch 2, an exhaust brake lever switch 3, an accelerator switch 4 which is turned ON when the accelerator is fully closed, a clutch switch 5 which is turned ON when the clutch is depressed to zero, and a vacuum solenoid valve 6 are connected in series to the power supply 1. There is. 7 is an exhaust brake pilot lamp, and 8 is an air filter.

Now, when the vehicle is running with the exhaust brake lever switch 3 in the ON state and you take your foot off the accelerator pedal to decelerate, the accelerator switch 4 will turn on.
ON is activated, and vacuum solenoid valve 6 is activated.
ON operates. Therefore, the negative pressure in the vacuum tank 9 acts on the exhaust brake actuator 10, causing the exhaust brake valve 12 provided in the exhaust pipe 11 to act on the exhaust brake actuator 10.
is fully closed. 13 is a shutter valve provided in the intake manifold 14, which is fully closed when the exhaust brake is operated. In this way, the engine performs negative work and acts as an auxiliary braking device. The auxiliary braking device is
It reduces the number of times the foot brake is used and the number of times the shift lever is operated, and generally improves operability and drivability.

(Problem that the invention aims to solve) However, in automatic transmission vehicles equipped with such conventional auxiliary braking devices, when the auxiliary braking device is activated and the shift lever is set in the low speed range to decelerate, excessive braking occurs. There was a problem in that the generation of power not only caused a loss of drivability, but also caused wheelspin and even created a feeling of anxiety for the occupants.

That is, at least excluding the highest speed range 2
When you shift to a low speed range such as 2nd or 3rd gear and decelerate, the gear that is currently engaged inside the transmission (2nd gear (while driving in 3rd gear) is decelerated in 2nd gear (shifted down), and then, for example,
Since the vehicle is downshifted to first gear at a relatively high speed of 60 km/h, the effect of the engine brake increases in combination with the effect of the auxiliary braking device, resulting in excessive braking force.

(Means and effects for solving the problem) This invention was made in view of the conventional problems, and its configuration is suitable for automatic transmission vehicles with a shift range of 3 or more speeds. The shift control device includes an operation switch for an auxiliary braking device, a shift lever position detection means for detecting that the shift lever of the automatic transmission is in a low speed range, and a vehicle speed for detecting that the vehicle speed is higher than a predetermined vehicle speed. It is equipped with a detection means and a solenoid device that biases a 1-2 shift valve that switches between 1st speed and 2nd speed to the 2nd speed side, and is based on detection signals from the operating switch, the shift lever position detection means, and the vehicle speed detection means. This is a shift control device for an automatic transmission vehicle that operates a solenoid device to energize a 1-2 shift valve.

When the operation switch is actuated and the auxiliary braking device is in operation, when the shift lever of the automatic transmission is shifted to the low speed range and the shift lever position detection means outputs a detection signal, the vehicle speed detection means As long as the detected vehicle speed is equal to or higher than a predetermined value, the solenoid device is energized and the 1-2 shift valve is biased toward the 2nd speed side. For this reason, automatic transmissions
Despite being shifted to the low speed range,
Maintain 2nd gear.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings, with the same reference numerals assigned to the same parts as in the prior art.

In Fig. 1, reference numeral 1 is a power supply, 2 is a key switch, 3 is an exhaust brake lever switch which is an operation switch for the auxiliary braking device, 4 is an accelerator switch, 6 is a vacuum solenoid valve, 7 is an exhaust brake pilot lamp, and 8 is an air 9 is a vacuum tank, 10 is an exhaust brake actuator 10, 11 is an exhaust pipe, 12 is an exhaust brake valve, 13 is a shutter valve, and 14 is an intake manifold, which is an exhaust brake device for automatic transmission vehicles. Therefore, a clutch switch is not provided.

A shift control mechanism 15 is provided in parallel with the vacuum solenoid valve 6. The shift control mechanism 15 is provided near the shift lever 16, and is a shift lever position detecting means that is turned on at least in the low speed range positions such as 2nd and 3rd speeds excluding the highest speed range of the shift lever 16. A position detection switch 17, a governor pressure detection means 18 which is provided in the hydraulic circuit of the automatic transmission and is a vehicle speed detection means for detecting a pressure higher than a predetermined value of the governor pressure corresponding to the vehicle speed, Solenoid device 1 that biases the 1-2 shift valve 33 to the 2nd speed side
9 are connected in series.

FIG. 2 shows an example of a hydraulic circuit for an automatic transmission to which such a shift control mechanism 15 is applied. This is a hydraulic circuit for an automatic transmission with three forward speeds and one reverse speed, and the manual valve 35 is shifted to the low speed range using the shift lever 16. However, since the vehicle speed is high, the 1-2 shift valve 33 is A state in which the engine is kept in the second speed state and prevented from overrun by receiving a large governor pressure in the chamber 33a is shown, and the line pressure circuit into which pressure oil from the oil pump 20 is introduced is shown in black.

In the figure, 20 is an oil pump, 21 is a torque converter, 22 is a governor valve, 23 is a pressure regulator valve, 24 is a pressure modifier valve, 25 is a top pre-distributing valve, and 26 is a front clutch. , 27 is a rear clutch, 28 is a brake band, 29 is a low & reverse brake, 30 is a 3-2 timing valve, 31 is a 3-2 downshift valve, 32 is a 2-3 shift valve, 33 is a 1-2 shift valve, 34 is the 1-2 back up valve, 35 is the manual valve, 36 is the day tent & failsafe valve, 37 is the throttle valve, 38 is the throttle modulator valve, 39 is the "1" reducing valve, and 40 is the accumulator valve,
41, 42, 43 are shuttle valves.

A governor pressure detection switch as governor pressure detection means 18 is provided in a pipe 44 connecting the chamber 32a of the 2-3 shift valve 32 and the chamber 33a of the 1-2 shift valve 33, and a governor pressure detection switch as the governor pressure detection means 18 is provided.
The spool 33b of the 1-2 shift valve 33 is biased toward the 2nd speed side, that is, upwardly in the drawing, by the operating rod 19a at No. 9.

Next, the effect will be explained.

Now, turn ON both key switch 2 and exhaust brake lever switch 3, and shift lever 1.
6 to the low speed range and transitions to coasting driving, both the accelerator switch 4 and the shift lever position detection switch 17 are turned on.

Here, the running speed of the vehicle is relatively high (approximately 60
Km/h or more), the chamber 33 is
The spool 33b is 2 due to the governor pressure supplied to the
It is pushed to the speed side and maintains the 1-2 shift valve 33 at the 2nd speed position. That is, when the manual valve 35 is shifted to the low speed range, the line pressure increases to the port 3.
5a and is supplied to the chamber 39a of the "1" reducing valve 39, pushing up the spool 39c against the spring 39b, so that part of the line pressure is drained from the drain port 39d and the spring 39b
The low speed range pressure balanced with the elastic force of 1-2
It acts on the upper end surface of the spool 33b of the shift valve 33. However, at high speed, the spool 33b is pushed to the 2nd speed side by the governor pressure from the pipe 44,
The 1-2 shift valve 33 is maintained at 2nd speed. Thus, in conjunction with the action of the auxiliary brake device, appropriate engine braking can be obtained.

Then, the vehicle travels at a relatively low speed,
When the governor pressure acting on the chamber 33a decreases, 1-
The spool 33b of the 2-shift valve 33 attempts to descend due to the low speed range pressure acting on the upper end surface of the spool 33b. However, as long as the governor pressure is above a predetermined value, the governor pressure detection means 18 is ON, so the solenoid device 19 is energized from the power source 1, and the operating rod 19a urges the spool 33b toward the second speed side. . Therefore, an appropriate braking force can be continuously obtained without causing excessive engine braking in the low speed range.

When the running speed of the vehicle further decreases and the governor pressure becomes less than a predetermined value, the governor pressure detection means 18 turns OFF.
Activated, the spool 3 by the solenoid device 19
3b is released and the 1-2 shift valve 33
The spool 33b is in a lowered state, and an appropriate braking force at low speeds can be obtained.

By the way, the governor pressure detection means 18 is configured with a switch that turns ON when the governor pressure is above a predetermined value and turns OFF when the governor pressure is less than a predetermined value. The electric quantity may be compared by a comparing means, and the solenoid device 19 may be excited based on this detection signal.

Further, the governor pressure detection means 18 may be any vehicle speed detection means that detects that the vehicle speed is equal to or higher than a predetermined vehicle speed.

In addition to the exhaust brake device, the auxiliary braking device may be any retarder such as an electromagnetic retarder.

(Effects of the invention) As understood from the above explanation, according to this invention, an automatic transmission equipped with an auxiliary braking device can be created by making only slight changes to the conventionally known hydraulic circuit of an automatic transmission. The braking force of the transmission vehicle is appropriately adjusted according to the shift range position and vehicle speed, resulting in improved drivability and the elimination of wheel spin and anxiety for passengers.

That is, the system is equipped with a vehicle speed detection means, and only when the vehicle is running at a predetermined speed or higher, downshifting from second gear to first gear is prohibited, excessive action of engine braking is prohibited, and the system relies on braking force from an auxiliary braking device. I tried to let him do it. Therefore, only the effect of engine braking when driving at relatively high speeds, which would normally result in a downshift to 1st gear, is successfully reduced, and after sufficient deceleration, the downshift to 1st gear is reduced. is allowed to ensure proper engine braking action. Further, although downshifting from second speed to first speed is prohibited as described above, downshifting from the highest speed range to the next range, etc. is not prohibited. Therefore, during high-speed driving, in addition to the braking force provided by the auxiliary braking device, appropriate engine braking can be obtained, for example, when downshifting from 3rd gear to 2nd gear. Note that while driving in the highest speed range, there is generally no need to decelerate as the vehicle is running at high speed, so the driver operates the operation switch 3 of the auxiliary braking device and shifts the shift lever to the low speed range. Only in such cases, it is assumed that a large deceleration is necessary and there is a possibility of downshifting to the first speed, and the shift control device of the present invention is configured to operate, thereby preventing unnecessary operation of the shift control device.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing one embodiment of this invention, FIG. 2 is a hydraulic circuit diagram of an automatic transmission, and FIG. 3 is a layout diagram showing a conventional structure. 3... Exhaust brake lever switch (auxiliary braking device operation switch), 16... Shift lever,
17...Shift lever position detection switch (shift lever position detection means), 18...Governor pressure detection means (vehicle speed detection means), 19...Solenoid device,
33...1-2 shift valve.

Claims (1)

[Scope of utility model registration request] A shift control device for an automatic transmission vehicle with a shift range of 3 or more speeds, which detects that the auxiliary braking device operation switch and the shift lever of the automatic transmission are in a low speed range. A detection means, a vehicle speed detection means for detecting that the vehicle speed is higher than a predetermined speed, and a solenoid device for biasing a 1-2 shift valve to the 2nd speed side for switching between 1st speed and 2nd speed. The solenoid device is actuated based on the detection signals from the lever position detection means and the vehicle speed detection means.
- A shift control device for an automatic transmission vehicle, characterized by energizing two shift valves.