JPS58145525A - Control method of engine brake in hydraulically operated speed changer and steering machine - Google Patents

Abstract

PURPOSE:To automatically operate an engine brake, by operating an engine brake switch to feed a control signal to a delivery amount control actuator of a hydraulic pump and controlling an engine to a preset speed. CONSTITUTION:A target engine speed NEB for an average car speed V at applying of an engine brake is stored to a logical operation circuit, and an engine brake signal I7 is output from a difference between said speed NEB and then engine speed signal nm, then signals (i), (j) to delivery control actuators 26, 27 of lateral hydraulic pumps are output through adders 91, 92 to actuators 26, 27 in such a manner that a difference between the speeds approximates to zero by said signal I7. In this way, an engine speed is convergently controlled to the speed NEB to obtain an optimum engine brake.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine brake control method for a hydromechanical transmission and steering device that is driven by an engine, has one input shaft, and is mainly used in tracked vehicles. The purpose is to provide an engine brake control method in which the engine brake is automatically activated when the engine rotation reaches a preset target engine rotation speed NICB by operating the engine brake switch. It's about doing.

The embodiments of the present invention will be described below with reference to the drawings. 2 I will explain.

In the figure, 1 indicates one input shaft 3 connected to the engine 2 and two (
a mechanical transmission having left and right output shafts 4.5; 6;
7 is two (left and right) hydraulic pumps driven by the engine 2, 8.9 is a hydraulic motor driven by the discharge oil of each hydraulic pump 6.7, and the output shafts of both motors 8 and 9 are The above gearbox! i11, and this hydraulic motor g,
9, the transmission 1 is configured to change speed steplessly within each speed stage. The transmission I has a clutch A for 1st speed, a clutch B for 2nd speed, a clutch C for 13th speed, and a clutch D for 4th speed, and by selectively operating each of them with hydraulic pressure, the output shaft speed can be changed to 4 or 50 rpm. The gears are changed from 1st to 4th speed.

11 is a throttle position detector that detects the throttle position that controls the engine 20 rotation speed and outputs a signal a from this; 12 is a throttle position detector that detects the turning angle of the steering wheel for turning the vehicle and outputs the signal a; Handle angle detector to take out,
: 3 is a change lever position detector that detects the four positions of the change lever: forward, reverse, neutral, and turning, and outputs the corresponding signal C; +4 is the signal d for applying the engine brake. +5 is the engine speed detector that takes out the engine speed a@nm according to the actual engine speed, 1
6.17 is the rotation speed signal -1, rl of each hydraulic motor 8, 9
Motor rotation speed detector, +8.19°20.2
1 is a hydraulic switch that detects the hydraulic pressure of the clutches A to D for 1st to 4th speeds and takes out the respective signals ew'+g+h; 22, 23, 24° 25 are the clutches A to 4th gears for 1st to 4th speeds; 1), the respective clutch changeover switches 26 and 27 are discharge amount control actuators for both pumps 6 and 7. 28 is a control logic circuit, and this circuit 28
When the above-mentioned signals a-h and -T n@1 HXS are input, both pumps 6.7
A signal 'wJ is applied to the discharge amount control actuator 26゜27,
In addition, the signals I, I,
It is designed to output m and n.

Specific examples of the actions of the method of the present invention and the control logic circuits for each action are shown below.

The speed change and steering device according to the present invention is controlled by engine speed control during normal driving 4, that is, K f is controlled so that the engine speed is optimal for the throttle position.
Since the engine is controlled by IIJ, engine braking cannot be applied by operating the throttle alone. Therefore, if it is desired to use the engine brake to brake the vehicle, control must be performed to forcibly apply the engine brake. Moreover, appropriate engine braking according to the vehicle speed is therefore possible.

Next, the specific control method will be explained with reference to FIG.

When there is a signal d from the engine brake switch I4, engine brake control is entered.

The engine rotation speed signal from the engine rotation speed detector 15, the motor rotation numbers n□, n□ from the left and right motor rotation speed detectors 16 and 17, and each 4+' of the oil pressure switches A-D of the stages. Based on the speed signal from the oil pressure switch of one speed step, the vehicle linkage operation unit 50 calculates the average vehicle speed V of the vehicle at the current speed step and outputs a vehicle speed signal V.

The target engine speed NIB for the average vehicle speed during engine braking is stored in a logic circuit, and the engine brake signal I7 is converted to the target engine speed from the difference between EB and the engine speed signal n1 at that time.
From this (g number I7, the above difference ('hcn - fi
The adder 9 sends signals i and j to the discharge amount control actuators 26 and 27 of the left and right hydraulic pumps so that = ) approaches zero.
1.92 to the discharge control actuators 26 and 27 of each pump 6.7. As a result, the engine rotation is brought to the engine braking rotation speed NICE, and optimum engine braking is obtained.

In addition, in the above embodiment, the target engine rotation speed N
It is also possible to set ICB in advance regardless of the average vehicle ■ and calculate the value of ICB with - to output the signal 1y.

The adders 91 and 92 are currently used (signal 1.j
This is an arithmetic unit that adds the engine brake signal +17 or -Iy to the engine brake signal. The present invention is as described above, and the signal d from the engine brake switch 14 causes the target rotation speed NKB to be 1727.
The engine brake signal 1y is output by comparing and calculating the actual engine speed -, and from this signal 17, both engine speeds NICB are determined.

Hydraulic pumps on the left and right so that the difference between n units approaches zero 6.7
Since the control signal is sent to the discharge amount control actuators 26 and 27 to control the vehicle speed and the engine brake is controlled, by operating the engine/engine brake switch I4, the engine speed is adjusted to the preset speed. When the engine speed reaches NEH, the engine brake is automatically activated.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a control system diagram, and FIG. 2 is a perspective view showing the implementation of the main part of the present invention. 1 is a transmission, 2 is an engine, 3 is an input shaft, 4.5 is an output shaft, 6 and 7 are hydraulic pumps, 8 and 9 are hydraulic motors, 14
is the engine brake switch, and 26.27 is the discharge amount control actuator.

Claims (1)

[Claims] A mechanical transmission 1 having one input shaft 3 connected to an engine 2, left and right output shafts 4, 5, and multi-stage hydraulic clutches A-D, and left and right drives driven by the engine 2. It consists of a hydraulic pump 6.7 and left and right hydraulic motors 8, 9 which are driven by the oil discharged from the hydraulic pump 6.7.
The output shaft of the above transmission IK is connected to the hydraulic motor 8.9.
In a hydromechanical transmission and steering device in which the transmission 1 is controlled so that the gears are changed steplessly at each speed stage, a signal d from the engine brake switch 14 is used to change the target engine speed NKB and the actual The engine speed is compared with 1 to generate an engine brake signal. Therefore, the vehicle speed is controlled by sending a control signal to the discharge amount control actuators 26 and 27 of the left and right hydraulic pumps 6°7 so that the difference between the engine speeds NIB and nm approaches zero. Engine brake control method for hydromechanical transmission and steering gear.