JPH05112216A - 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 compression coil spring 12 is accommodated in a cylinder body 9 in the condition that the spring is previously given an initial shrinkage, and thereby a piston rod 11 is energized in the direction of protruding from the cylinder body 9, to form a cylinder device 8, which is installed in such an arrangement that the tip of the piston rod 11 confronts the undersurface of a brake pedal 1. When the undersurface of the pedal contacts the tip of the piston rod 11 approx. in the middle of the pedal stroke S at the time of stamping the brake pedal 1, the initial shrinkage force of the spring 12 is added to the pedal stamping force, which thus increases rapidly, and the operator is given expressly a sense of stroke end.

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]

2. Description of the Related Art Generally, a brake pedal system for a vehicle is
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 54, and the relationship between the pedal stroke and the pedal effort (reaction force from the push rod 53 side) is generally Figure 6
As shown in, the characteristics are almost linear. 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.

Further, 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 first period of depression (normal braking region) 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 increases more than necessary, and durability is required more than before. Especially in the case of a forklift with a torque converter,
During the cargo handling work by operating the inching pedal, the operator tends to deeply depress the inching pedal in consideration of the unexpected movement of the vehicle due to the work pattern (the brake pedal is interlocked with the inching pedal depression direction) and always brakes. There is a problem in that the hydraulic pressure of the device 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 cylinder body, a piston housed in the cylinder body so as to be movable in the axial direction, and a cylinder body housed in a state in which initial compression is added in advance, the piston A cylinder equipped with a compression spring that presses in one direction is installed in the vicinity of the pedal link system, and when the brake pedal is depressed, the piston rod of the cylinder is part of the pedal link system in the vicinity of the normal braking range of the pedal stroke. The initial compression force of the compression spring is added to the pedaling force by abutting against 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. Push. Since the initial compression force of the compression spring is applied to the piston in advance, this initial compression force is added to the pedal effort. In other words, the pedal effort suddenly increases, during which the depression of the brake pedal is substantially prevented, and the operator can clearly feel the stroke end feeling. This prevents excessive depression of the brake pedal during normal use. In an emergency requiring sudden braking, the brake pedal can overcome the initial compression force of the compression spring and depress more strongly to bring out the required braking ability of the brake device.

A brake pedal device according to an embodiment of the present invention will be specifically described below with reference to the drawings. First, Fig. 1
Example 1 will be described with reference to FIG. 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). In addition, in FIG.
Reference numeral 6 indicates a floor, and 7 indicates a pivot of the brake pedal 1.

On the upper surface of the floor 6, a cylinder 8 for increasing the pedaling force is mounted facing the lower surface of the brake pedal 1 so as to face upward. The cylinder 8 includes a cylinder body 9 fixed to the upper surface of the floor 6, a piston 10 slidably accommodated in the cylinder body 9, and a piston rod 11 projecting upward from the cylinder body 9.
The compression coil spring 12 is housed in the cylinder body 9 and biases the piston 10 upward.

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. An initial contraction is added to the coil spring 12 in advance so as to preload the piston 10.

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 stroke A, the brake pedal 1 can be depressed with a light pedal force (reaction force from the push rod 3 side) as in the conventional case. On the other hand, 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, the reaction force of the compression coil spring 12 is added to the pedal effort.

In this case, the compression coil spring 12
Since an initial contraction has been added in advance, the pedal effort suddenly rises in the initial stage of the second stroke B. That is, the pedal depressing force rapidly increases until the lower surface of the pedal abuts the piston rod 11 and reaches a magnitude corresponding to the preload due to the initial contraction of the compression coil spring 12, during which 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 device 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 is 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, it is possible to avoid excessive depression of the brake pedal during normal use. 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, rotation of the 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 the compression coil spring is housed in the cylinder, and therefore, the brake pedal device can be mounted on an existing vehicle and is highly functionally reliable.

[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 ... Cylinder body 10 ... Piston 11 ... Piston rod 12 Compression coil spring

Claims (1)

[Claims] 1. A cylinder body, a piston movably accommodated in the cylinder body in the axial direction, and a piston accommodated in the cylinder body in a state where initial compression is applied in advance, and the piston is pressed in one direction. A cylinder equipped with a compression spring is installed near the pedal link system, and when the brake pedal is depressed, the piston rod of the cylinder comes into contact with a part of the pedal link system in the vicinity of exceeding the normal braking range of the pedal stroke. A brake pedal device configured to add the initial compression force of the compression spring to the pedal effort.