JPH05112221A - Brake pedal device of car - Google Patents

Abstract

PURPOSE:To reduce the frequency of generation of high pressure in a brake device by quickly increasing the pedal stamping force at the stage as going beyond the normal braking zone, and giving the operator a sense of stroke end. CONSTITUTION:A cylinder 6 provided for increasing the pedal stamping force is arranged so that its piston rod 11 faces the undersurface of a brake pedal 1. A compressed gas 12 is encapsulated in the cylindrical element 9 of this cylinder 8 in the pre-pressurized state, and thereby a piston 10 is pressed and energized. When the pedal undersurface comes in contact with the piston rod 11 approx. in the middle position of the pedal stroke S when the brake pedal 1 is going to be stamped, the initial pressurization force of the compressed gas 12 is added to the pedal stamping force to cause it to increase rapidly, and the operator is given a sense of stroke end expressly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pedal device suitable for vehicles, more specifically for industrial vehicles such as forklifts.

[0002]

Brake pedal devices for vehicles are generally
As shown in FIG. 5, the link system is established. FIG. 5 shows the case of an organ type brake pedal, and when the brake pedal 51 is depressed, the link arm 52,
The brake device 55 is operated via the push rod 53 and the master cylinder or the booster device 53. The relationship between the pedal stroke and the pedal effort (reaction force from the push rod 53 side) generally has a substantially linear characteristic as shown in FIG. However, in reality, there are some differences due to the play of the pedals, the change of the links, and the like. As the booster, a hydraulic booster, an air pressure booster, a vacuum booster, or the like is used, although it depends on the vehicle type.

In addition, depending on the vehicle, as shown in FIG. 7, a brake having a pedaling force characteristic such that a light pedaling force is obtained in the above-mentioned (normal braking region) of depression of the brake pedal, and the pedaling force gradually increases in the latter period of pedaling (emergency braking region). Pedal devices have been put to practical use. An example of such a brake pedal device is JP-B-63-21455.

[0004]

In recent years, in order to reduce the operator's fatigue, in order to obtain the desired braking ability with a light pedaling force, the link ratio of the brake operating system is increased,
In particular, improvements such as increasing the servo ratio of boosters have been made. However, while such an improvement measure is effective in reducing operator fatigue, it has the side effect that the pedal stroke easily reaches full stroke with a light pedal force, which means that the pedal stroke is relatively small. This is especially noticeable in the case of organ type brake pedals.

As a result, the load on the brake device has increased more than necessary, and durability has been required more than before. In particular, in the case of a forklift truck with a torque converter, during cargo handling work by operating the inching pedal, the operator depresses the inching pedal deeply in consideration of the unexpected movement of the vehicle due to the work pattern (the brake pedal interlocks with the inching pedal depression direction). Yes.)
There is a problem in that the hydraulic pressure of the brake device always rises to the maximum level, which adversely affects the life of the brake.

Even in the case of a brake pedal device having a pedaling force characteristic as shown in FIG. 7, it is actually difficult to clearly inform the operator of an inflection point (indicated by a broken line circle) at which the characteristic changes. Therefore, there is a high possibility that the pedal will be depressed more than necessary and the same problem as described above will occur.

By the way, the braking ability of the brake device is determined so as to comply with various standards and regulations in consideration of sudden braking in an emergency. However, it is known that the braking ability that is actually frequently used as the regular braking range is within half of the ability of the braking device.

In view of this, the present invention provides a stroke-end feeling to the operator by abruptly raising the pedal effort when the brake pedal is stepped up to the vicinity of the normal braking range. It is a technical problem to be solved to provide a brake pedal device that can reduce the frequency of high pressure generation in the brake device during normal use.

[0009]

In order to solve the above problems, the present invention is configured as follows. That is, in a brake pedal device for a vehicle, a hermetically sealed tubular body, a piston movably accommodated in the tubular body in the axial direction, and an initial pressure applied in advance in the tubular body are enclosed. A cylinder provided with a compressed gas and a piston rod which is integral with the piston and protrudes from the cylindrical body is arranged in the vicinity of a pedal link system of a brake pedal, and a regular braking area of a pedal stroke when the brake pedal is depressed. When a part of the pedal link system and the piston rod come into contact with each other in the vicinity of the range exceeding, the initial pressing force of the compressed gas is added to the pedal depression force.

[0010]

In the brake pedal device according to the present invention constructed as described above, when the brake pedal is depressed, a part of the pedal link system comes into contact with the piston rod in the vicinity of the normal braking range of the pedal stroke. Then, since the initial pressing force of the compressed gas enclosed in the cylinder acts on the piston, this initial pressing force is added to the pedal effort. Therefore, the pedal effort suddenly increases, during which the depression of the brake pedal is substantially prevented, and the operator feels the stroke end clearly. This prevents excessive depression of the brake pedal during normal use. In an emergency that requires sudden braking, the required braking ability of the brake device can be obtained by overcoming the initial pressing force of the compressed gas and further depressing the brake pedal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A brake pedal device according to an embodiment of the present invention will be specifically described below with reference to the drawings. First, a first embodiment will be described based on FIGS. 1 and 2. The brake pedal device of this embodiment is applied to an organ type brake pedal, and when the brake pedal 1 is depressed, the brake device 5 is operated via the link arm 2, the push rod 3, the master cylinder or the booster device 4. The configuration for activating is the same as the conventional one. The brake pedal 1 is held at the brake release position by a return spring (not shown). Further, in FIG. 1, 6
Indicates a floor, and 7 indicates a rotation fulcrum of the brake pedal 1.

A cylinder 8 for increasing the pedal effort is mounted on the upper surface of the floor 6 so as to face the lower surface of the brake pedal 1 and face upward. The cylinder 8 includes a cylindrical body 9 having an airtight structure fixed to the upper surface of the floor 6, a piston 10 slidably accommodated in the cylindrical body 9 and a piston rod 11 protruding from the cylindrical body 9. And a compressed gas 12 such as nitrogen gas sealed in the cylindrical body 9.

The height of the cylinder 8 is set so that the tip of the piston rod 11 comes into contact with the lower surface of the pedal at a substantially intermediate position during the pedal stroke S of the brake pedal 1, and the compression is performed. The gas 12 is pre-compressed at a predetermined pressure, that is, filled with an initial applied pressure.

The brake pedal device of this embodiment is constructed as described above, and when the brake pedal 1 is stepped on, the cylinder 8 moves in the pedal stroke S out of the pedal stroke S.
It does not operate in the front stroke A (normal braking range) up to approximately the middle position, and the remaining rear stroke B (emergency braking range)
Is operated by. Therefore, in the front-stage stroke A, the brake pedal 1 can be depressed with a light pedaling force (reaction force from the push rod 3 side) similar to the conventional one. On the other hand, the reaction force of the compressed gas 12 is added to the pedal effort in the second stage stroke B in which the lower surface of the pedal comes into contact with the tip of the piston rod 11 to operate the cylinder 8.

In this case, the compressed gas 1 is stored in the cylinder 8.
Since No. 2 is enclosed in a pre-compressed state, the pedal effort suddenly rises in the initial stage of the second stroke B. That is, the pedal effort is the brake pedal 1
After contacting the lower surface of the piston with the piston rod 11, it rapidly increases until it reaches a magnitude corresponding to the pressing force applied to the compressed gas 12, and during that time, the depression of the brake pedal 1 is substantially prevented. Therefore, it is possible to clearly convey the stroke end feeling to the operator.

Thus, according to the brake pedal system of the present embodiment, the pedal depression force characteristic in which the pedal depression force suddenly changes stepwise between the normal braking range and the emergency braking range as shown in FIG. 2 can be obtained. Therefore, the operator receives a stroke end feeling at an almost intermediate position of the pedal stroke S during normal use, thereby avoiding an excessive depression of the brake pedal 1 and further depressing harder in an emergency when sudden braking is sufficient. It is possible to secure a sufficient braking force.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is an example in which a cylinder 8 for increasing the pedal effort is attached to the lower surface of the floor 6, and the tip of the piston rod 11 of the cylinder 8 is at a substantially intermediate position between the link arm 2 of the brake pedal 1 and the pedal stroke S. It is set to abut. The other parts are the same as those in the first embodiment. Therefore, according to the brake pedal device of the second embodiment, in addition to the same operational effect as that of the first embodiment, the cylinder 8 mounted on the lower surface of the floor 6 is protected from rainwater, soil of shoe soles, mud, or the like. There is an advantage that can be protected.

FIG. 4 shows a third embodiment of the present invention. The third embodiment is a suspension type brake pedal 1
The piston rod 11 of the cylinder 8 is arranged and fixed downwardly above the link arm 2 so that the tip of the piston rod 11 of the cylinder 8 comes into contact with the link arm 2 of the brake pedal 1 at a substantially intermediate position of the pedal stroke S. .. Therefore, also in the case of such a suspension type brake pedal device, the same operational effect as in the case of the organ type brake pedal device can be obtained.

The above-described brake pedal device is particularly effective for a forklift that frequently uses the brake device, but the applicable range is not limited to the forklift and can be applied to other vehicles.

[0020]

As described in detail above, according to the present invention,
By giving the operator a stroke-end feeling in the vicinity of the normal braking range, excessive depression of the brake pedal during normal use can be avoided.
As a result, the frequency of occurrence of high pressure in the brake device is reduced, the load on the entire brake device is reduced, and the life of the brake device is extended. Further, the reduction in the high-pressure generation frequency also reduces the frequency of operation of the booster (for example, the frequency of operation of accumulating compressed air, rotating a vacuum pump, etc.), which contributes to energy saving. It becomes effective. Further, the brake pedal device of the present invention has an extremely simple structure in which compressed gas is filled in the cylinder, and has an advantage that it can be easily mounted on an existing vehicle.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a brake pedal device according to a first embodiment of the present invention.

FIG. 2 is a pedal stroke-pedal depression force diagram of the present invention.

FIG. 3 is an explanatory diagram of a brake pedal device according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a brake pedal device according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional brake pedal device.

FIG. 6 is a conventional standard pedal stroke-pedal depression force diagram.

FIG. 7 is a conventional improved pedal stroke-pedal pedal force diagram.

[Explanation of symbols]

1 ... Brake pedal 2 ... Link arm 8 ... Cylinder 9 ... Cylindrical body 10 ... Piston 11 ... Piston rod 12 ... Compressed gas

Claims (1)

[Claims] 1. A cylinder having a closed structure, a piston accommodated in the cylinder so as to be movable in the axial direction, a compressed gas sealed in the cylinder in a state where initial pressure is applied in advance, and A cylinder, which is integral with the piston and has a piston rod protruding from the cylindrical body, is arranged in the vicinity of the pedal link system of the brake pedal, and when the brake pedal is depressed, the pedal stroke exceeds the normal braking range of the pedal stroke. A vehicle brake pedal device configured such that an initial pressing force of the compressed gas is added to a pedal effort by contacting a part of a link system with the piston rod.