KR20140074623A - Method for Deceleration of Forklift Truck - Google Patents

Abstract

The present invention relates to a speed reducing method of a forklift truck using a hydraulic transmission. The speed reducing method of the forklift truck comprises the steps of: receiving, comparing and analyzing a gear selection signal, an acceleration pedal signal and a running speed (S) signal; comparing the running speed (S) with a first speed (B) or a second speed (C) which is previously set when the acceleration pedal signal is in an OFF state; and (S40, S60) controlling pressure of a gear clutch of the direction of a driver′s running selection or a gear clutch of the opposite direction of the driver′s running selection according to a result that the running speed is compared with the first speed (B) or the second speed (C).

Description

Method for Deceleration of Forklift Truck

The present invention relates to a method of decelerating a forklift, and more particularly, to a decelerating method of a forklift using only a clutch of a forklift without any additional device, thereby improving safety and efficiency.

Generally, a forklift truck is widely used for transporting a heavy cargo to a desired position by a worker, and the forklift is operated by controlling the number of revolutions of the engine according to the degree of operation of the accelerator pedal, .

In addition, the main purpose of the forklift is not to carry long-distance driving or high-speed travel in terms of work characteristics, but to move the short distance at a low speed after loading a heavy load. Therefore, in order to stop the forklift after traveling, the non-accelerating pedal is not stopped during the running, so that the deceleration is performed due to the friction between the ground and the forklift wheel.

However, since the deceleration is small, the forklift is quickly stopped by using additional devices such as a service brake or a retarder.

However, the deceleration method using the service brake or retarder is a method of deceleration by generating low force or friction on the rotary shaft connected to the driving wheel. In the case of frequent braking, there is a fear that the braking force is decreased due to overheating, There is a problem in the operation and maintenance of the forklift.

Registration No. 10-1089207 (Announcement of Dec. 2011)

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems, and the present invention is to reduce a forklift using a conventional hydraulic transmission without improving a brake system or an additional transmission structure. The present invention also relates to a method of decelerating a forklift in which a deceleration can be performed stepwise in order to reduce an unpleasantness of an operator due to deceleration.

In order to achieve the above object, a method of decelerating a forklift according to the present invention comprises:

(S10) of acquiring, comparing and analyzing a gear selection signal, an accelerator pedal signal and a traveling speed (S) signal, and comparing the traveling speed (S) with a predetermined first setting speed (B) Or the second set speed (C), and comparing the running speed (S) with the first set speed (B) or the second set speed (C) (S40, S60) of controlling the pressures of the travel-directional gear clutch or the travel-selective opposite-gear clutch.

When the accelerator pedal signal is OFF, the running speed S is compared with the first set speed B, and when the running speed S is greater than the first set speed B, The pressure of the gear clutch is controlled (S40)

When the running speed S is less than or equal to the first set speed B, the running speed S is compared with the second set speed C again so that the running speed S is lower than the second set speed B, And when it is greater than the speed (C), the driver-selected gear clutch pressure is minimized and the gear clutch pressure in the opposite direction to the drive selection is controlled.

The method further includes the step (S20) of maximizing the pressure of the driving direction gear clutch of the driver when the accelerator pedal signal is ON.

Further, the method may further include the step (S90) of minimizing the pressures of the forward clutch and the reverse clutch when the running speed S is less than or equal to the second set speed C.

The effect of the present invention is that first, the forklift can be effectively decelerated by controlling the hydraulic transmission without any additional configuration such as a braking device. Second, a stepped profile can be created and reduced to reduce the discomfort felt during the deceleration of the forklift.

1 is a sectional view of a transmission and a clutch pack of a forklift according to the present invention,
2 is a flowchart illustrating a method of decelerating a forklift according to the present invention,
3 is a profile and an explanatory view of a deceleration process of a forklift according to the present invention.

Hereinafter, a method of decelerating a forklift according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention. The present invention is not limited to the embodiments described herein, but may be embodied in many different forms. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

FIG. 1 is a sectional view of a transmission and a clutch pack of a forklift according to the present invention. As shown in FIG. 1, the forklift according to the present invention uses a hydraulic transmission.

The hydraulic transmission includes a drive shaft 100 having a first gear 510 and a second gear 530 provided along the outer circumferential surface thereof and having a first gear 510 and a second gear 530 provided in different teeth and sizes, And a first piston 115 and a second piston 125 connected to the first flow path 110 and the second flow path 120.

A spring 400 for pressing the piston in a predetermined direction is provided at one side of the first piston 115 and the second piston 125. That is, the spring 400 separates the first piston 115 from the left clutch pack, and separates the second piston 125 from the right clutch pack.

Accordingly, when the hydraulic oil does not flow into the first oil passage 110 and the second oil passage 120, the first piston 115 and the second piston 125 do not press the left clutch pack and the right clutch pack, respectively The clutch disc 310 and the friction member 330 are not in contact with each other and power is not transmitted to the first gear 510 and the second gear 530.

A bearing is provided between the first gear 510 and the second gear 530 and the drive shaft 100 so that the first gear 510 and the second gear 530 and the drive shaft 100 The rotational motion can be selectively transmitted.

Further, the forklift according to the present invention further includes a controller (not shown) for collecting and analyzing information on the gear selection signal, the accelerator pedal signal, and the speed signal.

The controller determines the direction in which the forklift advances (forward or backward), confirms whether the accelerator pedal operates, determines the operator's intention, measures the current operation speed of the forklift, To reduce discomfort during the deceleration process.

The controller obtains the gear selection signal, the accelerator pedal signal, and the speed information of the forklift to set the clutch pressure of the transmission. That is, according to the input information, the controller selectively flows the hydraulic oil into the first oil passage 110 and the second oil passage 120, and thereby the forward clutch or the reverse clutch is operated, and the transmission itself decelerates the forklift will be.

The operation of the transmission according to the present invention will be described below.

A plurality of clutch discs 310 constituting the clutch pack and the friction member 330 are brought into contact with the movement of the first piston 115 and the second piston 125, And selectively transmits the signals to the first gear 510 to the second gear 530.

In order to transmit the power to the first gear 510, the first piston 115 must be moved to the left so that the clutch disc 310 and the friction member 330 are in close contact with each other. To this end, the hydraulic oil flows through the first oil passage 110 and the first piston 115 is moved to an operating pressure formed by the operating oil.

Here, if the left clutch pack connected to the first gear 510, the first piston 115, and the first piston 115 is a forward gear and a forward clutch for forward movement of the forklift, the second gear 530 ), The second piston 125 and the right clutch pack connected to the second piston 125 can be regarded as a reverse gear and a reverse clutch for the backward movement of the forklift.

The method for decelerating the forklift according to the present invention proceeds as shown in FIG.

First, when the forklift starts operating according to an operator's instruction, the controller obtains a gear selection signal, an accelerator pedal signal, and a speed signal (S10);

When the accelerator pedal signal is ON, the gear clutch pressure in the driver's direction of travel selection is maximized (S20). That is, the operator maintains normal driving because there is an intention to continue driving.

If the running speed S is less than or equal to the first set speed B (S40). If the running speed S is less than or equal to the first set speed B, The running speed S is compared with the second set speed C.

That is, if S > B, the pressure of the currently operating gear clutch is maintained without being removed, while further controlling the pressure of the gear clutch in the opposite direction of travel to decelerate the speed.

When the running speed S decreases and becomes smaller than or equal to the first set speed B and then is again greater than the second set speed C and is greater than the second set speed C, the driver running select clutch clutch pressure is minimized, And the gear clutch pressure in the opposite direction is controlled (S60).

That is, until the traveling speed S becomes equal to or less than the second predetermined speed C, the pressure of the driver's direction selection gear clutch is minimized and the pressure of the gear selection clutch opposite to the selection direction is controlled to decelerate the speed of the forklift.

Accordingly, if the running speed S of the forklift is reduced and the running speed S is less than or equal to the second set speed C, both the forward and reverse clutch pressures are minimized (S90). Thus, the operation of the forklift is stopped.

Here, the traveling speed S may be a rated speed of the forklift or a speed of a constant speed state, the first predetermined speed B is a speed reduced by a certain magnitude in the traveling speed S, and the second predetermined speed C is the first predetermined speed B Is the speed at which a certain size is reduced.

For example, the first set speed B may be 10 km / h to 20 km / h, and the second set speed C may be set to 2 km / h to 9 km / h. In addition, the running speed S, the first set speed B, and the second set speed C can be variously set according to the type of forklift, the operation condition, the characteristics of the operator, and the operation condition.

In addition, the traveling speed and the set speed refer to a criterion that minimizes the discomfort felt by the operator during the traveling process and the deceleration process, so that the operator does not give any dulling or shaking due to unexpected deceleration in the deceleration process.

A method of decelerating a forklift according to the present invention shown in FIG. 2 will be described as follows.

When the accelerator pedal signal of the forklift is ON, the controller does not take any action because the operator intends to continue running in the forward or backward direction.

 When the accelerator pedal signal of the forklift is OFF, the operator is willing to stop the traveling in the forward or backward direction, so deceleration is required. Therefore, the controller compares the current running speed S with the first set speed B, and if S is larger than B, the controller does not remove the clutch pressure in the current running selection direction so that the operation of the rapid transmission does not cause an uncomfortable feeling of the operator, Deceleration while controlling the clutch pressure in the opposite direction of travel selection.

1, when the first gear 510 is a gear or a forward gear in the travel selecting direction, the second gear 530 is operated together with the first gear 510 The operating fluid flows into the second flow path 120 to operate the right clutch pack.

When the accelerator pedal signal of the forklift is OFF, the controller compares the running speed S with the second set speed C again when the current running speed S is less than or equal to the first set speed B. When the running speed S is larger than the second set speed C, the driver's clutch selection pressure is minimized and the clutch pressure in the opposite direction of the driving selection is controlled because the deceleration is performed to some extent.

Accordingly, when the running speed S due to the deceleration becomes smaller than or equal to the second set speed C, the pressures of the forward and reverse clutches are all minimized, The forklift can be stopped.

FIG. 3 illustrates the relationship between the speed reduction method of the forklift and the speed, the accelerator pedal signal, and the forward / backward clutch pressures described in FIG.

As shown in FIG. 3, when the operator operates the accelerator pedal to increase the speed of the forklift, the speed and the speed of the forklift, the controller obtains and compares the speed information of the accelerator pedal signal, the gear selection signal, and the forklift.

Accordingly, even if the accelerator pedal signal is turned OFF, the speed of the reverse clutch is reduced by not only minimizing the pressure of the traveling clutch (forward clutch) but also gradually decreasing the speed. When reaching the first set speed B, Minimize the clutch pressure and control only the reverse clutch.

Therefore, the method of decelerating the forklift according to the present invention can reduce the discomfort of the operator with the clutch pack of the transmission without any additional deceleration device by comparing the information obtained from the controller and the deceleration.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. And such changes are, of course, within the scope of the claims.

The present invention can be applied to a method of decelerating a forklift using only a clutch without an additional device to improve safety and efficiency.

100: drive shaft 110: first flow path
115: first piston 120: second flow path
125: second piston 300: clutch pack
310: clutch disc 330: friction member
400: spring 510: first gear
530: Second gear

Claims (4)

A method of decelerating a forklift using a hydraulic transmission,
(S10) of obtaining, comparing and analyzing the gear selection signal, the accelerator pedal signal, and the traveling speed (S) signal;
(S50, S70) comparing the traveling speed (S) with a predetermined first predetermined speed (B) or a second predetermined speed (C) when the accelerator pedal signal is OFF; And
Controlling the pressure of the driving selection direction gear clutch or the traveling-selection-direction opposite gear clutch of the driver according to the result of comparing the traveling speed S with the first set speed B or the second set speed C (S40, S60); And the speed of the forklift.
The method according to claim 1,
When the accelerator pedal signal is OFF, the running speed S is compared with the first set speed B, and when the running speed S is greater than the first set speed B, (S40). Then,
When the running speed S is less than or equal to the first set speed B, the running speed S is compared with the second set speed C again so that the running speed S is lower than the second set speed B, And when it is larger than the speed (C), the driver's drive select clutch clutch pressure is minimized and the gear shift opposite clutch drive clutch pressure is controlled.
The method according to claim 1,
Further comprising the step (S20) of maximizing the pressure of the direction selector gear clutch of the driver when the accelerator pedal signal is ON. The method according to claim 1,
Further comprising a step (S90) of minimizing a pressure of the forward clutch and the reverse clutch when the traveling speed (S) is less than or equal to the second predetermined speed (C).

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