JP2001253327A - Brake device for industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric detection type brake device allowing operation with an operation feeling of a conventional hydraulic brake device. SOLUTION: In this brake device 10, a stepping amount of a brake pedal 14 is converted into an electric signal, and a control part 16 decelerates a vehicle according to the electric signal. The brake device 10 is provided with the brake pedal 14 turnable between a waiting position A and a maximum stepping position B around a support shaft 13; and a main return spring 17 and a sub return spring 18 energizing the brake pedal 14 against stepping force such that the brake pedal 14 is returned toward the waiting position A. The main return spring 17 energizes the brake pedal 14 toward the waiting position A in a play range D and an operation range E, while the sub return spring 18 energizes the brake pedal 14 toward the waiting position A only in the operation range E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake device provided for an industrial vehicle such as a forklift.

[0002]

2. Description of the Related Art As a conventional brake device of this type, there is a hydraulic brake device 40 as shown in FIG. That is, the driving portion of the vehicle is
Brake pedal 42 is in standby position A and maximum depressed position B
It is attached so as to be rotatable between and. The brake pedal 42 is connected to a master cylinder 43 that converts the pedaling force applied to the brake pedal 42 into a hydraulic pressure.
The master cylinder 43 and the drum brake 44 (or disc brake) are connected by a hydraulic pipe 45,
The drum brake 44 operates according to the hydraulic pressure supplied from the hydraulic pipe 45. A return spring 47 (tensile coil spring) is provided between the fixed frame 46 provided in the driving section and the brake pedal 42 to return the brake pedal 42 in the direction of the standby position A against the pedaling force. ing.

Further, the play range D in which the drum brake 44 does not act from the standby position A to a certain stepping position C is defined as an play range D in which the drum brake 44 acts from the constant stepping position C to the maximum stepping position B. The range is set as E.

According to this, a hydraulic brake device 40 is provided.
In FIG. 6, the relationship between the depression force applied to the brake pedal 42 and the stroke of the brake pedal 42 is as shown in the graph of FIG. That is, within the play range D after the brake pedal 42 is started to be depressed, the stroke of the brake pedal 42 increases in proportion to the depressing force, and thereafter, at the switching point F from the play range D to the operation range E, the master cylinder Since a hydraulic pressure is generated in 43 and the pressurizing process starts, a flat portion H in which the stroke becomes almost constant with an increase in the pedaling force appears. After passing through the flat portion H, the stroke increases again in proportion to the pedaling force, and the drum brake 44 operates.

The characteristics of the hydraulic brake device 40 have been described above. Another type of brake device different from the hydraulic brake device 40 is an electric detection type brake device 50 as shown in FIG.

That is, the angle of the brake pedal 42 is detected by a potentiometer 51, the depression amount of the brake pedal 42 is calculated from the detected angle and converted into an electric signal, and the control unit 52 controls the braking force in accordance with the electric signal. It is configured to control.

[0007] Such an electric detection type brake device 5
At 0, the relationship between the depressing force applied to the brake pedal 42 and the stroke of the brake pedal 42 is a linear proportional relationship as shown in the graph of FIG. The flat portion H does not appear at the switching point F to the range E.

[0008]

However, in the above-mentioned conventional type, the relationship between the pedaling force and the stroke of the brake pedal 42 in the hydraulic brake device 40 shown in FIG. 6 and the electric detection type brake shown in FIG. Since there is a difference in the relationship between the pedaling force of the device 50 and the stroke of the brake pedal 42, the operator who is accustomed to the operational feeling of the hydraulic brake device 40 can use the electric detection type brake device 5.
When operating 0, there is a problem that the operation feeling is uncomfortable and it takes time to get used to.

An object of the present invention is to provide an electric detection type brake device which can be operated with a sense of operation of a general hydraulic brake device.

[0010]

According to a first aspect of the present invention, there is provided an industrial vehicle in which the amount of depression of a brake pedal is converted into an electric signal, and a control unit decelerates the vehicle in accordance with the electric signal. In the brake device, the brake pedal is rotatably provided around a fulcrum between a standby position and a maximum depressed position, and an play range where a braking force does not act from the standby position to a fixed depressed position. The main urging tool and the auxiliary urging tool for urging the brake pedal to return to the standby position against the depressing force are defined as an operation range in which the braking force acts from the constant depressed position to the maximum depressed position. An urging tool is provided, the main urging tool urges the brake pedal toward the standby position in the play range and the operating range, and the auxiliary urging tool only moves in the operating range. Those that are configured to bias toward the standby position Rekipedaru.

According to this, when the brake pedal at the standby position is depressed, only the main urging tool urges the brake pedal toward the standby position within the play range after the depression of the brake pedal is started. As a result, the stroke of the brake pedal increases in proportion to the pedaling force.

Thereafter, when the play area is switched from the play range to the operation range, in the operation range, both the main urging tool and the sub urging tool urge the brake pedal in the direction of the standby position. The brake pedal stroke increases.

Here, at the switching point from the play range to the operation range, the urging force of the sub urging device is applied to the urging force of the main urging device to act on the brake pedal. Unless the pedaling force is greater than the urging force, the brake pedal cannot be depressed, and as a result, a flat portion appears in which the stroke becomes almost constant as the pedaling force increases. Therefore, the operator can operate with the same operational feeling as the conventional hydraulic brake device.

According to the second aspect of the present invention, a main return spring is used as a main biasing tool, and a sub-return spring is used as a sub-biasing tool. Is engaged with a pedal-side engaged portion provided on the brake pedal, and the other engaging portion is engaged with a fixed-side engaged portion fixed to a driving portion of the vehicle, and When the pedal is at the standby position, it corresponds to a play range either between the one engaging portion and the pedal-side engaged portion or between the other engaging portion and the fixed-side engaged portion. Is formed.

[0015] According to this, within the play range after the brake pedal is started to be depressed, the engagement between one of the engaging portions and the engaged portion on the pedal side (or the other engaging portion and the fixed engaged portion on the fixed side). ), There is a margin for the clearance, so that only the main return spring urges the brake pedal in the direction of the standby position, and no urging force is generated in the auxiliary return spring.

In the operating range, the clearance is absorbed, so that one engaging portion and the pedal-side engaged portion engage with each other, and the other engaging portion and the fixed-side engaged portion engage with each other. Therefore, both the main return spring and the auxiliary return spring bias the brake pedal toward the standby position.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. Reference numeral 1 denotes a hydraulically driven forklift (an example of an industrial vehicle), whose drive system is a hydrostatic pump 4 (hereinafter, referred to as an HST pump) by an engine 3 provided in a vehicle body 2.
The HST pump 4 converts hydraulic oil into a high-pressure fluid, sends the hydraulic oil to a plurality of hydraulic drive motors 5 through hydraulic piping, and rotates the wheels 6 with the hydraulic drive motors 5.

The HST pump 4 is a variable displacement swash plate type (axial) piston pump, and the amount of hydraulic oil discharged is changed by changing the inclination angle of a built-in swash plate (not shown). It is configured so that it can be changed. That is, when the inclination angle of the swash plate is reduced, HS
Since the amount of hydraulic oil supplied from the T pump 4 to the hydraulic drive motor 5 is reduced, the rotation speed of the hydraulic drive motor 5 is reduced, and when the inclination angle of the swash plate is set to 0, the HST pump 4 moves to the hydraulic drive motor 5. The supply of the hydraulic oil is stopped, so that the wheels 6 are in a braking state.

Such a forklift 1 is provided with a brake device 10 of an electric detection type. The structure of the brake device 10 will be described below. A brake pedal 14 is mounted on a floor plate 12 of a driving unit 11 formed on the vehicle body 2 via a support shaft 13 supported in a horizontal direction. The brake pedal 14 is configured to be rotatable up and down between a standby position A set above and a maximum depression position B set below using the support shaft 13 as a fulcrum.

A potentiometer 15 for detecting the angle of the brake pedal 14 and converting the angle into an electric signal corresponding to the amount of depression is connected to the brake pedal 14. In addition, other than the potentiometer 15, another position sensor or an angle detection sensor may be used. The vehicle body 2
Is provided with a control unit 16 that changes the inclination angle of the swash plate of the HST pump 4 based on an electric signal from the potentiometer 15.

The stroke of the brake pedal 14 is from the standby position A to the constant depression position C.
A play range D in which the inclination angle of the swash plate of the HST pump 4 does not change (that is, no braking force is applied) is defined as H. The range from the constant stepping position C to the maximum stepping position B is defined as H.
The ST pump 4 is distinguished as an operation range E in which the inclination angle of the swash plate decreases (that is, the braking force acts).

The brake device 10 has a main return spring 17 (an example of a main biasing tool) and a sub return spring 18 for urging the brake pedal 14 to return toward the standby position A against the pedaling force. (An example of an auxiliary biasing tool).
The main return spring 17 includes hooks 17a, 1 at both ends.
A tension coil spring having 7b is used. Also,
The auxiliary return spring 18 has hooks 18a, 18b at both ends.
A tight-wound tension coil spring that has (an example of an engaging portion), and in which the windings come into close contact with each other when shortened in a no-load state is used.

One hook 17a of the main return spring 17
Are engaged with pedal-side main engaged holes 19 formed in the brake pedal 14. Also, the other hook 17b
Is a main fixing pin 20 attached and fixed to the operation unit 11.
Is engaged. The one hook 17a and the pedal-side main engaged hole 19 and the other hook 17b and the main fixing pin 20 are engaged over the entire stroke from the standby position A to the maximum depression position B. Accordingly, the main return spring 17 urges the brake pedal 14 toward the standby position A in the play range D and the operation range E.

One hook 18a of the auxiliary return spring 18 is engaged with a pedal-side auxiliary engaged hole 21 formed in the brake pedal 14 (an example of a pedal-side engaged portion). Further, the other hook 18b is engaged with a sub-fixing pin 22 (an example of a fixed-side engaged portion) that is attached and fixed to the driving unit 11.

As shown in FIG. 2, the pedal-side sub-engaged hole 21 is a long hole which is long in the vertical direction.
When the hook 4 is at the standby position A, the one hook 18a is inserted through the lower end of the pedal side sub-engaged hole 21 and the one hook 18a is located between the hook 18a and the upper end of the pedal side sub-engaged hole 21. Is formed with a clearance 23 corresponding to the play range D. As a result, the auxiliary return spring 18 is extended only in the operating range E and urges the brake pedal 14 toward the standby position A.

The operation of the above configuration will be described below.
Depressing force and brake pedal 1 in the brake device 10
The relationship with the stroke of No. 4 is as shown in the graph of FIG.
That is, as shown in FIG. 1, when the brake pedal 14 at the standby position A is depressed, within the play range D after the brake pedal 14 starts to be depressed, as shown in FIG. The clearance 2 is required until the upper end 18a engages the upper end of the pedal side sub-engaged hole 21.
Since there is a margin of three minutes, the auxiliary return spring 18 remains in a contracted state without being pulled by the brake pedal 14, and only the main return spring 17 is pulled by the brake pedal 14. As a result, only the main return spring 17 urges the brake pedal 14 in the direction of the standby position A, so that the stroke of the brake pedal 14 increases in proportion to the pedaling force as shown in the play range D in the graph of FIG. .

Thereafter, at the switching point F from the play range D to the operation range E, the brake pedal 14 rotates to the depressed position C as shown by the phantom line in FIG. One of the hooks 1 of the auxiliary return spring 18
8a is engaged with the upper end of the pedal side sub-engaged hole 21. Therefore, the clearance 23 is absorbed and the main return spring 1
The urging force (tensile force) of the auxiliary return spring 18 is applied to the urging force (tensile force) of the auxiliary return spring 18 to act on the brake pedal 14, so that the urging forces (tensile force) of these two return springs 17, 18 are applied.
The brake pedal 14 cannot be further depressed from the depressed position C unless the pedaling force is greater than the pedaling force. Thereby, as shown in the graph of FIG. 6, a flat portion H in which the stroke becomes almost constant with the increase in the pedaling force appears.

When the depressing force applied to the brake pedal 14 becomes larger than the urging force (tensile force) obtained by adding the urging force of the main return spring 17 and the urging force of the auxiliary return spring 18, the imaginary line in FIG. As shown in FIG.
The main return spring 17 and the sub-return spring 18 are both pulled by the brake pedal 14 because the arm rotates within the operation range E from the stepping position C. As a result, as shown in the graph of FIG.
Since both 7 and 18 urge the brake pedal 14 in the direction of the standby position A, the stroke of the brake pedal 14 increases in proportion to the depression force.

As described above, in the process in which the brake pedal 14 switches from the play range D to the operation range E, as shown in the graph of FIG. As a result, the operator can operate the electric detection type brake device 10 with the same feeling as a conventional hydraulic brake device.

In the above embodiment, the main return spring 17 and the sub return spring 18 have different spring constants, but they may be the same. In the above embodiment, when the brake pedal 14 is at the standby position A, the position between the one hook 18a of the sub return spring 18 and the upper end of the pedal-side sub-engaged hole 21, as shown by the solid line in FIG. A clearance 23 is formed on the other hook 18b and the auxiliary fixing pin 22 as shown in FIG.
3 may be formed. The pedal-side sub-engaged hole 21 is
Instead of a long hole, it is formed as a round hole having a diameter into which one hook 18a can be inserted.

According to this, when the brake pedal 14 at the standby position A is depressed, the upper end of the other hook 18b of the sub return spring 18 is connected to the sub fixing pin 22 within the play range D after the brake pedal 14 starts being depressed. The auxiliary return spring 18 remains in a contracted state without being pulled by the brake pedal 14, and only the main return spring 17 is pulled by the brake pedal 14. As a result, only the main return spring 17 urges the brake pedal 14 in the direction of the standby position A, so that the stroke of the brake pedal 14 increases in proportion to the pedaling force as shown in the play range D in the graph of FIG. .

Thereafter, at the switching point F from the play range D to the operation range E, the brake pedal 14 rotates to the depressed position C as shown by the phantom line in FIG. The upper end of the hook 18b is the sub-fixing pin 2.
2 is engaged. Therefore, the clearance 23 is absorbed, and the urging force (tensile force) of the main return spring 17 is applied to the urging force (tensile force) of the auxiliary return spring 18, so that the brake pedal 1 is released.
4, the brake pedal 14 cannot be further depressed from the depressed position C unless the depressing force is greater than the urging force (tensile force) of the two return springs 17, 18. Thereby, as shown in the graph of FIG. 6, a flat portion H in which the stroke becomes almost constant with the increase in the pedaling force appears.

[0033]

As described above, according to the present invention, at the switching point from the play range to the operation range, the urging force of the sub urging tool is added to the urging force of the main urging tool to apply a force to the brake pedal. The brake pedal cannot be depressed unless the pedaling force is greater than the biasing force of these two biasing tools,
As a result, a flat portion where the stroke is almost constant with the increase in the pedaling force appears. Therefore, the operator can operate with the same operational feeling as the conventional hydraulic brake device.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a brake device for an industrial vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram showing details of an engagement portion between a double return spring and a brake pedal of the brake device for an industrial vehicle.

FIG. 3 is a schematic diagram showing a hydraulic drive system of the industrial vehicle.

FIG. 4 is a view of an auxiliary return spring of a brake device for an industrial vehicle according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a conventional hydraulic brake device.

FIG. 6 is a graph showing a relationship between a pedaling force and a stroke of a brake pedal in the hydraulic brake device.

FIG. 7 is a diagram illustrating a configuration of a conventional electric detection type brake device.

FIG. 8 is a graph showing a relationship between a pedaling force and a stroke of a brake pedal in the electric detection type brake device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forklift (industrial vehicle) 10 Brake apparatus 11 Operating part 13 Support shaft 14 Brake pedal 16 Control part 17 Main return spring (main biasing tool) 18 Secondary return spring (secondary biasing tool) 18a, 18b Hook (engagement part) 21) Pedal-side sub-engaged hole (pedal-side engaged part) 22 Sub-fixing pin (fixed-side engaged part) 23 Clearance A Standby position B Maximum depressed position C Constant depressed position D Play range E Operating range

Claims (2)

[Claims] 1. A brake device for an industrial vehicle in which a depression amount of a brake pedal is converted into an electric signal, and a control unit decelerates the vehicle in accordance with the electric signal. Is provided rotatably between the maximum depressed position and the depressed position.The range from the standby position to the depressed position is a play range where the braking force is not applied. A main urging tool and a sub urging tool are provided to act as an operating range, and to urge the brake pedal to return to the standby position against the pedaling force. The main urging tool is provided in the play range. And the actuation range urges the brake pedal in the direction of the standby position, and the auxiliary urging device is configured to urge the brake pedal in the direction of the standby position only in the operation range. Brake system for industrial vehicle, characterized in that there. 2. A main return spring is used as a main biasing tool, and a sub-return spring is used as a sub-biasing tool. Is engaged with a pedal-side engaged portion provided on the brake pedal, and the other engaging portion is engaged with a fixed-side engaged portion fixed to a driving portion of the vehicle, and the brake pedal is in a standby position. A clearance corresponding to the play range is formed between the one engaging portion and the pedal-side engaged portion or between the other engaging portion and the fixed-side engaged portion. The brake device for an industrial vehicle according to claim 1, wherein the brake device is used.