JPH03157252A - Brake device for industrial vehicle - Google Patents

Abstract

PURPOSE:To relieve a brake pedalling force burden to an operator by a method wherein an assist means to hold a brake release pedal in a brake release position during pedalling of the brake release pedal is disposed in a pedalling force transmission system. CONSTITUTION:When a brake release pedal 5 is pedalled, a cam shaft 8a is rotated through a link mechanism 6 and a shift lever 7 to unfold two brake levers 3 and therefore, a brake pad is separated away from a brake disc 2 to release a brake. Simultaneously, a support shaft 13 of the link mechanism 6 is rotated along with pedalling of the brake release pedal 5, and at a point of time when the brake release pedal 5 is pedalled to a maximum pedalling position being a brake release position, a detent ball 17 energized through the force of a detent spring 16 is engaged with a detent groove 14 formed in the support shaft 13. As a result, the brake release pedal 5 is held by a detent mechanism 18, and a brake pedalling burden to an operator is relieved by an amount equivalent to an amount by which the brake release pedal is held by the detent mechanism.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a brake device used in an industrial vehicle such as a forklift. This invention relates to a so-called Dettman type brake device.

(Prior Art) This type of conventional brake device is mainly used in single-wheel forklifts. In this system, a pair of brake levers are arranged so as to sandwich a brake disc connected to the rotating shaft of the travel motor, and the base ends of both brake levers are rotatably supported by a common pin, and the tips are usually A brake spring attached to the side urges both brake levers toward each other, and a brake disc is sandwiched between brake pads attached to the brake levers, thereby applying the brake. When the release pedal is depressed, a roughly elliptical cam disposed between the other ends of the brake levers is rotated via a pedal depression force transmission mechanism to widen the distance between the brake levers and move the brake pad to the brake disc. The brake is released by pulling away from the brake. Note that the return of the brake release pedal to its original position is performed by a return spring that is separate from the brake spring. As such a mechanical disc brake HE, for example, the Japanese Utility Model Application Publication No. 1-17
No. 8057 can be mentioned.

(Problem to be Solved by the Invention) However, in the case of the above-mentioned dead man type brake device, the operator must constantly depress the brake release pedal in order to release the brake while the vehicle is running. Therefore, the operator must always maintain a pedal force sufficient to overcome the reaction force of the brake (combined force of the brake spring and return spring), which poses a problem of placing a large burden on the feet. Note that setting the spring force of the brake spring to be weak in order to reduce the above-mentioned load will reduce the effectiveness of the brake, so in reality, such a measure is not possible.

In view of the above problems, the present invention aims to provide a brake device for an industrial vehicle that can reduce the pedal force required to maintain the brake in a released state without deteriorating the effectiveness of the brake. That purpose.

(Means for Solving the Problems) In order to solve the above problems, the following measures are taken in the present invention.

That is, in the present invention, the brake is actuated by pressing a friction member against a brake disc or brake drum using a brake spring, and the friction member is pulled from the brake disc or brake drum against the brake spring by pressing a brake release pedal. In a brake device for an industrial vehicle configured to release the brake by releasing the brake, the brake release pedal is held at an arbitrary position in a pedal depression force transmission system including the brake release pedal at a brake release position when the brake release pedal is depressed. The brake pedal is equipped with a pedal depression force assisting means which acts in this manner and whose holding force is set to be somewhat weaker than the spring force of the brake spring.

(Function) In the brake device configured as described above, when the brake release pedal is depressed to the brake release position to release the brake, the pedal depression force assisting means operates to maintain the brake release pedal in the depression position. do. Therefore,
The operator can maintain the pedal in the brake release position with the assistance of the pedal force assisting means, and the burden of pedal force at this time is reduced. Since the holding force of the pedal force assisting means is weaker than that of the brake spring, if the pedal force by the operator is removed, the brake operation by the brake spring is performed without any problem. In other words, the pedal depression force assisting means operates only at the brake release position, which is the final stage of the depression stroke of the brake release pedal, and does not operate during the brake release position.

(Example) Hereinafter, an example of the present invention applied to a reach type forklift will be specifically described based on the drawings.

<Embodiment 1> First, a Dettman type mechanical disc brake device will be explained based on FIGS. 3 to 5. In the figure, reference numeral 1 denotes an electric motor for running that is arranged vertically, and although not shown, one end (lower end) of the rotating shaft of the electric motor 1 is connected to a drive wheel via a gear reducer. The electric motor 1, gear reducer, and drive wheels are supported as a drive unit by a vehicle body frame 10 via a suspension. A brake disc 2 is connected to the other end (upper end) of the rotating shaft of the electric motor 1.
A pair of upper and lower brake levers 3 are provided with brake pads 3a, which are friction members, on opposite sides of the brake levers. The brake lever 3 is located at its base end (
The left end in the figure) is rotatably supported by a common pin 3b, and is constantly biased in a direction to press both brake pads 3a against the brake disc 2 by a brake spring 4 attached to the tip end side.

On the other hand, a substantially oval cam 8 is disposed between the tips of the upper and lower brake levers 3. This cam 8 is a cam shaft 8 of a shift lever 7 which is tilted via a link mechanism 6 which is a pedal depression force transmission means when the brake release pedal 5 is depressed.
When the brake release pedal 5 is depressed, the brake lever 3 is expanded and the brake pad 3a is separated from the brake disc 2, thereby releasing the brake. Oh, when the brake release pedal 5 is depressed to the brake release position, the rotation angle of the cam 8 is normally set at approximately 60 degrees with respect to the horizontal line. The spring force of the spring 4 acts from the cam 8 through the link mechanism 6 in a direction to return the brake release pedal 5 to its original position.

Further, the brake release pedal 5 has one end connected to the vehicle body frame 10.
The cam 8 is always biased in the direction of brake activation by a return spring 9 whose other end is locked to a part of the link mechanism 6. This causes the cam 8 to move away from the brake lever 3 when the brake is activated. Completely remote position,
In other words, the brake release pedal 5 and the link mechanism 6 are held in an attitude in which the long axis is horizontal, and the shaking of the brake release pedal 5 and the link mechanism 6 is suppressed. Note that 11 in the figure indicates the upper surface of the floor of the driver's seat.

Next, referring to FIGS. 1 and 2, a description will be given of a pedal depression force assisting means that acts to maintain the brake release pedal 5 at the same position when the brake release pedal 5 is depressed to the brake release position. In this embodiment, this pedal depression force assisting means is composed of a detent mechanism 18, and includes a support shaft 12 of the brake release pedal 5 and a link in the linkage mechanism 6 in the pedal depression force transmission system that connects the brake release pedal 5 and the cam 8. This is carried out with respect to any fixed point rotation part such as the support shaft 13 or the camshaft 8a of the shift lever 7. In this embodiment, a case will be described in which the support shaft 13 in a link mechanism is assembled.

That is, a substantially V-shaped detent groove 14 is formed on the outer periphery of the support shaft 13 that rotates together with the link, and a detent spring 16 and a detent groove 14 are formed on the holder 15 side for rotatably supporting the support shaft 13. A detent ball 17 is provided which is biased by a detent spring 16, and its relative position is set such that the detent ball 17 engages with the detent groove 14 when the brake release pedal 5 is depressed to the brake release position. ing. The holding force of the detent machine MI118 determined by the detent spring 16 is set to be somewhat weaker than the combined force of the brake spring 4 and return spring 9.

The mechanical disc brake device of this embodiment (which is configured as described above), therefore, when the operator gets into the driver's seat and depresses the brake release pedal 5, the link mechanism 6
Since the cam 8 rotates via the shift lever 7 and spreads both brake levers 3, the brake pad 3a separates from the brake disc 2 and the brake is released. In addition,
Depressing the brake release pedal 5 at this time requires a pedal depression force that overcomes the combined force of the return spring 9 and the brake spring 4.

On the other hand, when the brake release pedal 5 is depressed, the support shaft 13 of the link mechanism 6 rotates in the direction of the arrow as shown in FIG. 1, and the brake release pedal 5 is depressed to the maximum depression position, which is the brake release position. At this point, the detent groove 14 formed in the support shaft 13 corresponds to the detent ball 17, so the detent ball 17, which is biased by the detent spring 16, engages with the detent groove 14 as shown in FIG. The engagement force at this time acts as a force to hold the brake release pedal 5 at the brake release position. That is, when the brake release pedal 5 is depressed to the brake release position, the pedal depression force by the operator is reduced by the holding force valve provided by the detent mechanism 18.

Furthermore, when the pedal release pedal 5 is released,
Since the combined force of the brake spring 4 and the return spring 9 is greater than the holding force of the detent spring 16, the support shaft 13 rotates in the direction of the arrow in FIG. 2, and the detent ball 17 escapes from the detent groove 14. be done. Then, the brake levers 3 are pulled toward each other by the brake spring 4, and the brake pad 3a clamps the brake disc 2, thereby applying the brake, and the pedal release pedal 5 is returned to the initial position by the return spring 9. Jumps up to brake application position. In other words,
The detent spring 16 does not adversely affect braking performance.

<Embodiment 2> Next, Embodiment 2 regarding the pedal depression force assisting means according to the present invention will be described based on FIG. 6. This Example 2 is
The pedal depression force assisting means is constructed using magnets. That is, while the iron plate 19 is attached to the back surface (lower surface) of the brake release pedal 5, the ! A magnet 20 is attached to the upper surface 11 of the core, and when the brake release pedal 5 is depressed to the brake release position, the iron plate 19 is attracted to the magnet 20, causing the play 4 = WI release pedal 5 to be moved to the same position. The structure is such that a holding force is added to hold the brake spring 4, and the holding force is applied to the brake spring 4 as in the previous embodiment.
It is set to be somewhat weaker due to the combined force of the return spring 9 and the return spring 9.

In the case of Embodiment 2 using such a magnet, compared to Embodiment 1 described above, the number of component parts is smaller and assembly is easier, so it has a significant advantage in terms of manufacturing cost. It has the advantage of being

In addition, even in the case of a pedal depression force assisting means using a magnet, it is not limited to the brake release pedal 5 as in the case of the first embodiment, but it can also be applied to links that are constituent members of the link mechanism 6 which is a pedal depression force transmission system. This can be implemented between a rod or the like and the vehicle body frame 10, which is a fixed member.

In addition, although the illustrated embodiment is explained in the case where it is applied to a mechanical disc brake, the application is not limited to this, and it can also be applied to a drum brake, and the pedal depression force transmission system is similar to the illustrated link mechanism. It is not limited to a mechanical type, and may be a type using a cable or a hydraulic type. In addition, the holding force of the pedal depressing horn assisting means is set to be somewhat weaker than the combined force of the brake spring 4 and the return spring 9, but in the case of a configuration without a return spring, the holding force of the pedal depressing horn assisting means is set to be slightly weaker than the spring force of the brake spring 4 alone. Naturally, it is also set weakly.

(Effects of the Invention) As described in detail above, according to the present invention, a part of the pedal depression force required to keep the brake release pedal depressed at the brake release position is borne by the pedal depression force assisting means. The burden of pedal effort on the operator can be reduced. Moreover, the pedal depression force assisting means of the present invention acts only at the brake release position, and does not have any adverse effect on braking performance.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1 and 2 are cross-sectional views showing a first embodiment of the pedal force assisting means, FIG. 3 is an overall explanatory diagram of a Dettman type brake device, and FIG. 4 is a similar diagram. The plan view and FIG. 5 are side views showing the braking section in particular.
FIG. 6 is a side view showing a second embodiment of the pedal depression force assisting means. 3a... Brake pad 5... Brake release pedal 8... Cam 19... Steel plate 4... Brake spring 6... Link mechanism 18... Eye tent mechanism 20... Magnet

Claims (1)

[Claims] Activate the brake by pressing a friction member against a brake disc or brake drum with a brake spring,
A brake device for an industrial vehicle configured to release a brake by pulling a friction member away from a brake disc or a brake drum against the brake spring by depressing a brake release pedal, wherein the brake release pedal is depressed. a pedal set at an arbitrary position in the pedal force transmission system including the brake release pedal so as to hold the pedal in the brake release position when the pedal is depressed, and whose holding force is somewhat weaker than the spring force of the brake spring; A brake device for industrial vehicles equipped with pedal effort assisting means.