JPH0580375B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a vehicle brake system.

[Conventional technology]

In various construction machines, work vehicles, etc., the transmission mechanism is a hydraulic-mechanical type that can perform stepless transmission by combining a hydraulic pump/motor with a mechanical transmission mechanism such as a planetary gear reducer. Continuously variable speed hydraulics are often used.

In a vehicle transmission and a tracked vehicle variable speed steering device having such a hydraulic-mechanical continuously variable transmission mechanism,
Engine braking force (engine braking effectiveness) can be arbitrarily selected by speed ratio control at any vehicle speed. Conventionally, this speed ratio control is performed based on the amount of depression of the accelerator pedal. For example, as shown in Fig. 5, in a range where the amount of depression of the accelerator pedal is small, the engine brake is activated, and as the amount of depression increases, the normal Acceleration operations are now being performed. When a vehicle is to be braked when there is a brake pedal for normal service braking, both the engine brake using the accelerator pedal and the service brake using the brake pedal are operated simultaneously or alternately.

[Problem that the invention seeks to solve]

As mentioned above, when attempting to brake a vehicle with a conventional hydrostatic-mechanical continuously variable transmission mechanism or a tracked vehicle, both the engine brake using the accelerator pedal and the service brake using the brake pedal are operated simultaneously or alternately. This makes the driving operation complicated and is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake device that eliminates the drawbacks of the conventional example and allows both engine braking and service braking to be operated using only the brake pedal.

[Means and actions for solving problems]

The vehicle brake system of the present invention stores the relationship between the brake pedal position and the engine target rotation speed during engine braking in advance in a setting device, and adjusts the speed ratio by controlling the discharge amount of the transmission hydraulic pump. By increasing or decreasing the actual engine speed, the actual engine speed is always driven at the target speed determined by the brake pedal position, so the degree of engine braking can be arbitrarily selected simply by operating the brake pedal, regardless of the vehicle speed. This is what made it possible. Therefore, with this device, it is possible to perform two types of normal service braking and engine braking at the same time only by operating the brake pedal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 2 is a block diagram of an embodiment of the invention. FIG. 1 is a block diagram of the main components of a brake device according to the present invention. 1st to 2nd
In the figure, 1 is a brake device, 3 is an engine, 2 is a hydrostatic-mechanical continuously variable transmission, and 5 is its output shaft.
Reference numeral 4 denotes an input shaft of the hydrostatic mechanical continuously variable transmission 2, which is connected to the engine 3. The hydrostatic-mechanical continuously variable transmission 2 has inside thereof a variable speed oil pump motor and a mechanical speed change mechanism that generally includes a plurality of speed stages. Reference numeral 6 is an actuator such as an electro-hydraulic servo valve or an electro-hydraulic proportional control valve for controlling the discharge amount of the transmission hydraulic pump, and is connected to the hydrostatic-mechanical continuously variable transmission 2. Reference numeral 7 is an actuator for selecting each speed stage, which is connected to the hydrostatic-mechanical continuously variable transmission 2.
It is connected to the. Reference numeral 8 denotes a service brake, which is provided on the output shaft 5 of the hydrostatic-mechanical continuously variable transmission 2, and is connected to a brake pedal 9 and a mechanical, hydraulic, or electrical brake (not shown) over a wide range of the amount of depression of the brake pedal. It is connected to the. 9 is a brake pedal, and 10 is a brake pedal position detection device provided on the brake pedal 9. Reference numeral 11 denotes an engine rotation speed detector, which is provided on the input shaft 4 of the hydrostatic-mechanical continuously variable transmission 2; and 12, a vehicle speed detector, which is provided on the output shaft 5 of the hydrostatic-mechanical continuously variable transmission 2. ing. Reference numeral 21 denotes an engine brake setting device that stores the engine target rotation speed relative to the brake pedal position. A is the output of the brake pedal position detector, which is a brake pedal position signal, and is input to the engine brake setting device 21. 22 is a speed deviation detector. ne is an engine target rotation speed signal output from the engine brake setting device 21, and N _E is an engine rotation speed signal output from the engine rotation speed detector 10, both _of which are input to the speed deviation detector 22. _Δne is the output of the speed deviation detector 22 and is input to the polarity addition circuit 23. _Np is a vehicle speed signal output from the vehicle speed detector 12. 24 is a speed ratio calculation circuit which receives the engine speed signal N _E and the vehicle speed signal N _p and outputs a speed ratio signal X.
25 is a speed stage logic circuit. A is a speed stage selection signal outputted by the speed stage logic circuit 25 and transmitted to the speed stage selection actuator 7 and the polarity adding circuit 2.
3 is input. Δn _ep is a polarized deviation signal and is the output of the polarity adding circuit 23. 26 is an integrator which receives the polarized deviation signal Δn _ep as input. D is a shift hydraulic pump discharge amount control signal, which is the output of the integrator 26, and is input to the shift hydraulic pump discharge amount control actuator 6.

Next, the operation of the above embodiment will be explained. The hydrostatic-mechanical continuously variable transmission 2 connects the engine 3 with its input shaft 4.
By controlling the rotation speed and direction of the internal transmission hydraulic pump motor, and by selecting the speed stage of a mechanical transmission mechanism consisting of multiple speed stages, Speed ratio x = (rotational speed of output shaft 5 of transmission 2; the signal is
n _e )/(rotational speed of the input shaft 4 of the transmission 2 and its signal
Since N _E ) can be arbitrarily selected in the range from 0 to a certain value, the rotation speed of the output shaft 5 of the transmission 2 can be arbitrarily controlled steplessly in the range from 0 to a certain value. When the output shaft 5 is forcibly reverse-driven from the outside and rotates at a certain number of revolutions, such as when driving with reduced engine output, such as when driving downhill, the discharge amount of the shift hydraulic pump should be adjusted. By controlling the speed ratio x by increasing or decreasing it, the engine speed can be controlled inversely. This is the speed ratio x no matter what the vehicle speed is.
This means that the degree of engine braking can be arbitrarily selected by controlling the amount of engine braking. The rotation speed and rotation direction of the transmission hydraulic motor are controlled by controlling the discharge amount of the transmission hydraulic pump hydraulic oil by the transmission oil pump discharge amount control actuator 6. Selection of each speed stage is performed by a speed stage selection actuator 7. service brake 8
are mechanically, hydraulically, or electrically interlocked (not shown) over a wide range of depression amounts of the brake pedal 9.

The engine brake setting device 21 stores in advance the engine target rotation speed for each position of the brake pedal 9, so when the brake pedal position signal a is input, the engine brake setting device 21 outputs the engine target rotation speed signal n _e . . Speed deviation detector 2
2 outputs a deviation signal Δn _e to the polarity addition circuit 23 when the engine target rotational speed signal n _{e and the engine revolutions per minute signal N E are} input. Note that Δn _e = |n _e −N _E
| is. When the engine speed signal N _E and the vehicle speed signal N _p are input to the speed ratio calculation circuit 24 , the speed ratio calculation circuit 24 outputs a speed ratio signal X to the speed stage logic circuit 25 . X=N _p /N _E. Since the width (range) of the speed ratio x value is unique for each speed stage, the speed stage logic circuit 25 determines which speed stage the current speed ratio is in based on the input speed ratio signal X. A speed stage selection control signal A for selecting a speed stage is output to each speed stage selection actuator 7. The speed stage selection control signal A is also input to the polarity adding circuit 23. The polarity addition circuit 23 adds positive, negative, or 0 polarity to the deviation signal Δn _e depending on the state of the speed stage selection control signal A, and outputs a polarized deviation signal Δn _ep to the integrator 26 . The integrator 26 integrates the polarized deviation signal Δn _ep and outputs a shift hydraulic pump discharge amount control signal D to the shift oil pump discharge amount control actuator 6 . The polarity added by _the polarity adding circuit 23 is determined in the direction in _which the speed ratio (b) If (engine speed signal N _E ) < (engine target speed signal N _e ), the speed ratio x decreases (c) (engine speed signal N _E ) = (engine target speed In the case of the number signal N _e ), the speed ratio x is added so as to maintain its value.

(d) When (engine speed signal N _E ) > (engine target speed signal N _e ), the transmission hydraulic pump discharge amount control signal D is output in the direction of increasing the speed ratio x, thereby increasing the engine speed. It acts to reduce

(e) When (engine rotational speed signal N _E ) < (engine target rotational speed signal N _e ), the transmission oil pump discharge amount control signal D is output in the direction of decreasing the speed ratio x, thereby causing the engine rotational speed It acts to increase the

(f) When (engine speed signal N _E ) = (engine target speed signal N _e ), the transmission oil pump discharge amount control signal D is output so that the speed ratio x maintains its value, and the engine speed acts to keep constant.

Through the processes (d), (e), and (f) above, the actual engine speed is converged to the target engine speed, and it becomes possible to arbitrarily select the engine braking force by operating the position of the brake pedal. By the above-described operation, the brake pedal can be operated without being affected by the original service brake. Therefore, in this embodiment, only the engine brake is operated by the brake pedal in a range where the amount of depression is small, and as the amount of depression increases, the service brake is also activated.

An example in which the present invention is applied to a hydrostatic-mechanical continuously variable transmission steering system for a tracked vehicle having one input shaft and two output shafts will be explained with reference to FIG.

FIG. 3 is a block diagram of a hydrostatic-mechanical continuously variable transmission steering system in which a transmission section and a steering section are independent of each other and a service brake is provided within the steering section. In Fig. 3, 33 is the engine, 32
is hydrostatic pressure - mechanical continuously variable transmission, 34 is hydrostatic pressure -
The input shaft of the mechanical continuously variable transmission, 35 is the hydrostatic pressure -
This is the output shaft of the mechanical continuously variable transmission 32. 36 is a hydraulic pump discharge amount control actuator for speed change, 37
38 is a steering device, 39 and 40 are left and right output shafts, 41 is a service brake provided on the output shaft 39, and 42 is a service brake provided on the output shaft 40, respectively. Reference numeral 11 denotes an engine rotation speed detector, which is provided on the input shaft 34. A vehicle speed detector 12 is provided on the output shaft 35 of the hydrostatic-mechanical continuously variable transmission 2. Hydrostatic pressure for this tracked vehicle
As mentioned above, in the mechanical continuously variable transmission steering device, the transmission section and the steering device section are independent of each other, so the operation related to the transmission device is explained previously in Figures 1 and 2.
Since it is the same as that explained using the figures, the explanation will be omitted. Since the effect is the same, it will be omitted. An example of application to a hydrostatic-mechanical continuously variable speed steering system in which a transmission unit and a steering unit are installed in one case and service brakes are provided on the left and right output shafts will be explained with reference to FIG. do. FIG. 4 is a block diagram.

In the figure, 55 is a hydrostatic-mechanical continuously variable speed steering device. Reference numeral 44 indicates the hydrostatic pressure - the input shaft of the mechanical continuously variable speed steering device 55, 48 and 49 indicate the left and right output shafts, respectively, and 46 indicates the hydrostatic pressure - the hydrostatic pressure inside the mechanical continuously variable speed steering device 55. A mechanical continuously variable transmission section 47 is a steering device section located in the hydrostatic-mechanical continuously variable transmission steering device, and 50 and 51 are service brakes provided on the left and right output shafts 48 and 49, respectively. 52 is a hydraulic pump discharge amount control actuator for speed change, 53 is an actuator for selecting each speed stage, and 54 is the hydrostatic-mechanical continuously variable transmission section 4.
6 output shaft. The power of the engine 43 is transmitted through the input shaft 44 of the hydrostatic-mechanical continuously variable transmission steering device 55 to the hydrostatic-mechanical continuously variable transmission within the hydrostatic-mechanical continuously variable transmission steering device 55. Device section 4
6 and a steering device section 47, and after being given the required speed change steering action, the signal is transmitted to the left and right output shafts 48, 49. The engine rotation speed detector 11 is connected to the input shaft 44 of the hydrostatic-mechanical continuously variable speed steering device 55.
The vehicle speed detector 12 is provided on the output shaft 54 of the hydrostatic-mechanical continuously variable transmission section 46. In FIG. 4, the arrows on the lines indicate the direction of power transmission, and the ◯ marks indicate the combination and branching points of the power. The service brakes 50, 51 provided on the left and right output shafts 48, 49 and the brake pedal 9 are connected by a conventional mechanical, hydraulic or electrical interlocking mechanism (not shown). The engine rotation speed detector 11 is provided on the input shaft 44 of the hydrostatic-mechanical continuously variable transmission steering device 55, and the vehicle speed detector 12 is provided on the output shaft 54 of the hydrostatic-mechanical continuously variable transmission section 46. However, since these detectors are originally signal detectors for calculating the speed ratio, other parts of the hydrostatic-mechanical continuously variable speed steering system 55 can be used as long as the speed ratio can be calculated as a result. It may be placed at an appropriate location.
In the embodiment shown in the block diagram as shown in FIG. 4, the transmission section and the steering section are operationally independent, so the action related to the hydrostatic-mechanical continuously variable transmission section is the same as that of the first transmission section. Since it is the same as that explained with reference to FIG. 2, the explanation will be omitted. The effect is also similar.

[Effects of the Invention] As mentioned above, the brake device of the present invention is used for a vehicle transmission having a hydrostatic mechanical continuously variable transmission mechanism and a speed change steering device for a tracked vehicle, and includes a brake pedal and a brake pedal. a position detector, an engine brake setting device that stores an engine target rotation speed relative to a brake pedal position, an engine rotation speed detector, an engine target rotation speed output from the engine brake setting device, and the engine rotation speed detector. A speed deviation detector that calculates the absolute value of the deviation from the output of The output of this integrator is used as the output of the braking device, and this output is used to increase or decrease the speed ratio via a shift hydraulic pump discharge amount control actuator, thereby changing the actual engine rotation speed to the engine target rotation. Since the brake pedal has the function of operating the original service brake, it is possible to operate both the engine brake and the service brake with only the brake pedal, for example, the amount of depression of the brake pedal. It can be set in advance so that only the engine brake operates in a range where the amount of depression is small, and the service brake also starts to operate as the amount of depression increases.

[Brief explanation of the drawing]

FIG. 2 is a block diagram of an embodiment of the present invention;
The figure is a block diagram of an embodiment of the brake device of the present invention, and FIG. 3 is a block diagram of an embodiment of a variable speed steering device in which the transmission section and the steering device section are independent of each other and the steering device section has a service brake. Figure 4 is a block diagram of an embodiment of a transmission steering system in which a transmission unit and a steering unit are installed in one case, and service brakes are provided on the left and right output shafts. FIG. 2 is an explanatory diagram of the operation of a conventional brake pedal. DESCRIPTION OF SYMBOLS 1... Brake device, 2... Continuously variable transmission, 3... Engine, 6, 7... Actuator, 9... Brake pedal, 21... Engine brake setting device, 22...
Speed deviation detector, 23... Polarity adder, 24, 2
5, 7...Means for selecting a speed stage, 26...Integrator,
N _E ...Engine speed signal, n _e ...Engine target speed signal corresponding to the amount of brake pedal depression, X
…Speed ratio (N _p /N _E ), x…Speed ratio (n _e /N _E ), N _p
...Vehicle speed detection signal, Δn _e ...deviation, Δn _ep ... polarity-related deviation.

Claims (1)

[Claims] 1. In a transmission having a hydraulic-mechanical continuously variable transmission mechanism that performs continuously variable transmission by combining a hydraulic pump/motor and a mechanical transmission mechanism, a target rotational speed of the engine is set in accordance with the amount of depression of the brake pedal. an engine brake setting device; a speed deviation detector that calculates a deviation between a detected value of the engine speed and the target speed; and a speed deviation detector that calculates a speed ratio from the detected value of the vehicle speed and the detected value of the engine speed; means for selecting a speed stage corresponding to the ratio; a polarity adder that outputs a polarized deviation corresponding to the selected speed stage; and a control unit that integrates the polarized deviation value to control the discharge amount of the transmission hydraulic pump. A vehicular brake device comprising an integrator that outputs an operation signal to an actuator.