JPH0311088Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a braking device for a vehicle that is useful for stopping on a slope, starting on a slope, preventing creep in an automatic transmission, etc.

(Prior art) As this type of braking device, for example,
There is a device as shown in Publication No. 121760, and after braking by activating the hydraulic brake by depressing the brake pedal, the accelerator opening is 0 and the vehicle speed is 0.
If so, these are detected electrically and the hydraulic pressure of the hydraulic brake is maintained by electromagnetic operation of the solenoid even when the brake pedal is released, thereby maintaining the braking state.

As a result, the vehicle can be stopped on a slope even if the brake pedal is released, but if the accelerator is opened by depressing the accelerator pedal while the brake pedal is released when starting, the brake is deenergized due to the deactivation of the solenoid. The vehicle can be started on a slope by removing the hydraulic pressure and disabling this brake, making it possible to drive.

(Problem that the invention aims to solve) However, since such a braking device only controls whether to maintain or remove the hydraulic pressure of the brake, the hydraulic pressure of the brake is removed all at once when starting on a slope. At this time, the vehicle temporarily backed up, and after that the engine power was transmitted to the drive wheels.
A problem arises in that a large starting shock occurs.

(Means for solving the problem) The present invention attempts to solve the above-mentioned problem by changing the hydraulic pressure of the brake according to the accelerator opening and vehicle speed. Depending on the speed and speed of the vehicle, the stopped state is maintained by the hydraulic operation of the brake.
In a vehicle that is enabled to run by deactivating the brake, a throttle valve that generates a throttle pressure that corresponds to an accelerator opening, a governor valve that generates a governor pressure that corresponds to a vehicle speed;
It is characterized by a configuration that includes a pressure regulating valve that changes the hydraulic pressure of the brake in response to the throttle pressure and governor pressure so that the required braking force is obtained.

(Function) The pressure regulating valve responds to the throttle pressure from the throttle valve, which corresponds to the accelerator opening, and the governor pressure, which corresponds to the vehicle speed, from the governor valve, and changes the brake hydraulic pressure according to the accelerator opening and vehicle speed. In this way, the braking force of the brake operated by this hydraulic pressure can be set to the required value determined for each accelerator opening degree and vehicle speed, making it possible to start the vehicle without backing up when starting on a slope, and preventing the occurrence of a starting shock. This also makes the subsequent start-up and running smoother.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 shows an embodiment of the braking device of the present invention.
2 indicates a wheel drive shaft, 2 indicates a wheel, and 3 indicates a hydraulically operated brake. Axis 1 uses power from a transmission to directly or indirectly drive wheels 2 to drive the vehicle, and brake 3 is connected to circuit 4. Working oil pressure from
It is assumed that the vehicle is actuated by P _B to prevent rotation of the wheels 2 and bring the vehicle to a stopped state. Note that the brake 3 can be provided directly on the wheel 2 or directly on the shaft 1, but in the former case, an existing brake can also be used for each wheel of the vehicle.

In the present invention, a pressure regulating valve 5 is provided for adjusting the brake operating oil pressure P _S , and this valve is provided with a spool 7 slidably fitted in a housing 6, and the spool is held upward in the figure by a spring 8. to energize. A chamber 9 in which the pressure receiving surface 7a of the spool 7 faces inside the housing 6
A chamber 10 facing the pressure receiving surface 7b and a chamber 11 facing the pressure receiving surface 7c are set respectively.The chamber 9 is connected to the output port of the governor valve 13 by the circuit 12, and the chamber 10 is connected to the output port of the throttle valve 15 by the circuit 14. and the chamber 11 is connected to the circuit 4 through a circuit 17 into which an orifice 16 is inserted.

The governor valve 13 receives a constant line P _L from the circuit 18, and when it rotates together with the shaft 1, the governor pressure is proportional to its rotational speed (vehicle speed).
Output P _G to circuit 12. In addition, the throttle valve 15 receives the line pressure P _L from the circuit 18, and in conjunction with the accelerator pedal 19 outputs a throttle pressure _PTH proportional to the amount of pedal depression (accelerator opening) to the circuit 14. .

The pressure regulating valve spool 7 is normally located above the illustrated position by the spring 8, and connects the circuit 4 to the circuit 18.
Circuit 4 is supplemented with line pressure P _L from circuit 18.
The hydraulic pressure P _B is generated. This working oil pressure P _B is fed back from the circuit 17 to the pressure receiving surface 7c,
Together with the governor pressure P _G and throttle pressure P _TH acting on the pressure receiving surfaces 7 a and 7 b, the spool 7 acts against the spring 8 . The spool 7 stops at a position where the forces due to these forces are balanced, and the working oil pressure P _B acting in feedback on the pressure receiving surface 7c is low.
When the spool 7 is above the position shown, the circuit 4
is passed through the circuit 18 to increase the working oil pressure P _B. Conversely, when the working oil pressure P _B is high and the spool 7 is located below the illustrated position, the circuit 4 is passed to the drain port 20 to lower the working oil pressure P _B.

The operation of the above embodiment will be explained next. When the accelerator pedal 19 is released and the throttle pressure _PTH is 0 (when the accelerator opening θ is 0), the spool pressure receiving surface 7b
There is no hydraulic pressure acting on the Therefore, the spool 7 receives the downward force due to the governor pressure P _G acting on the pressure receiving surface 7a and the hydraulic pressure acting on the pressure receiving surface 7c.
A downward force by P _B and an upward force by the spring 8 act, and the operating oil pressure P _B is reduced as the governor pressure P _G (vehicle speed) increases, as shown in FIG. 2A, for example. As the accelerator opening θ increases,
Since the throttle pressure P _TH , which increases accordingly, acts on the pressure receiving surface 7b, the working oil pressure P _B has the same tendency as A, but decreases over the entire vehicle speed range, and when the accelerator opening θ is 1/8 It changes as shown in B in Figure 2, and as shown in C in the same figure when the accelerator opening θ is 2/8.

Here, the brake 3 operates when the hydraulic pressure P _B is higher than P _B1 in Fig. 2, and the brake 3 operates when the hydraulic pressure P B is lower than that.
Assuming that the braking force is reduced and deactivated as P _B decreases, when the vehicle speed is 0 km/h, the brake 3 will not be deactivated unless the accelerator opening θ is 1.6/8 or more. /h, accelerator opening θ
When the brake is set to 1.1/8, the brake 3 becomes inactive, and when the vehicle speed is over 10 km/h, the hydraulic pressure is adjusted so that the brake 3 becomes inactive regardless of the accelerator opening θ.
P _B can be controlled.

Therefore, when the accelerator opening θ is set to 0 and the vehicle speed is 0, the brake 3 operates reliably and the vehicle can be stopped on a slope even if the foot brake (not shown) is deactivated. Thereafter, even if the accelerator opening degree θ is increased by depressing the accelerator pedal 19, the brake 3 is kept in an activated state until the accelerator opening degree θ becomes 1.6/8 or more, thereby preventing the vehicle from moving backward on a slope. Then, adjust the accelerator opening θ to 1.6/8
By transmitting the engine power to the wheels 2 during the above process, the brake 3 is gradually deactivated, and the vehicle can be started smoothly without a shock.

Even during this running after the start, the brake 3 is deactivated depending on the vehicle speed, so that the running can be carried out smoothly. And the vehicle speed is 10km/
During normal driving over h, the brake 3 is kept inactive regardless of the accelerator opening θ, so even if the accelerator pedal 19 is released for engine braking, etc. (even if the accelerator opening θ is set to 0). Normal driving is not hindered by the operation of the brake 3.

(Effect of the invention) Thus, as described above, the braking system of the present invention is configured to change the brake hydraulic pressure P _B in accordance with the throttle pressure P _TH corresponding to the accelerator opening and the governor pressure P _G corresponding to the vehicle speed. , the braking force of the brake 3 can be set to a required value determined for each accelerator opening degree and vehicle speed, the vehicle can be started without backing up when starting on a slope, and the occurrence of a starting shock can be reliably prevented. In addition, starting and running can be done smoothly.

Furthermore, since the device of the present invention is hydraulically controlled, it can be incorporated into a transmission, and if this transmission is an automatic transmission, the governor valve and throttle valve inside the transmission can be used as they are, simplifying the configuration. It is particularly advantageous in that it can be used as a creep prevention device for automatic transmissions.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the device according to the present invention, and FIG. 2 is a diagram showing changes in brake operating pressure according to the device according to the present invention. DESCRIPTION OF SYMBOLS 1...Wheel drive shaft, 2...Wheel, 3...Hydraulic operated brake, 5...Pressure regulating valve, 6...Valve housing, 7...Spool, 8...Spring, 13...Governor valve, 15...Slot Tutoruro Valve, 19...
...Accelerator pedal, P _TH ...Throttle pressure, P _L ...
...Line pressure, P _G ...Governor pressure, P _B ...Brake operating oil pressure.

Claims (1)

[Scope of Claim for Utility Model Registration] The vehicle is equipped with a hydraulically operated brake, and depending on the accelerator opening degree and vehicle speed, the vehicle is maintained in a stopped state by hydraulically operating the brake, or is enabled to travel by not operating the brake. The vehicle includes a throttle valve that generates a throttle pressure according to the accelerator opening degree, a governor valve that generates a governor pressure according to the vehicle speed, and a hydraulic pressure for the brake in response to the throttle pressure and the governor pressure. A braking device for a vehicle, comprising a pressure regulating valve that changes the pressure so as to obtain a required braking force.