JP3321299B2 - Hydraulic winch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic winch device suitable for being mounted on a hydraulic crawler crane used for crane work or clamshell work.

[0002]

2. Description of the Related Art The present applicant has previously described Japanese Patent Publication No. 2-41509.
Discloses a hydraulic winch device with good operability. FIG. 5 is a diagram showing this type of hydraulic winch device, in which 1 is a hydraulic motor, 2 is a planetary reduction mechanism that reduces the output of the hydraulic motor 1, and a planetary reduction mechanism.
This planetary reduction mechanism includes a sun gear 2a, a planetary gear 2
b, carrier 2c, carrier shaft 2d and ring gear 2
e, a sun gear 2a is connected to the output shaft of the hydraulic motor 1, 3 is a winch drum integrally connected to the ring gear 2e of the planetary reduction mechanism 2, and 4 is a planetary reduction mechanism 2.
The first brake device 6 for braking the input side of the first brake device 6 is a hydraulic brake cylinder that incorporates a spring 5 for a braking operation and controls the braking operation of the first brake device 4. 7, a brake drum integrally connected to the carrier shaft 2d; 8, a second brake device for braking the brake drum 7;
This is a foot brake pedal that controls braking and release of the second brake device 8.

[0003] One port of the hydraulic motor 1 is connected to one port of a direction switching valve 13 by an oil path 11 including a counterbalance valve 10, and the other port of the hydraulic motor 1 is connected by an oil path 12 to a direction switching valve. 13 are connected to other ports. The direction switching valve 13 is connected to the main pump 14 and the oil tank 15, and is switched by an operation lever 16 between three switching positions of a neutral position, a forward rotation position, and a reverse rotation position. The hydraulic brake cylinder 6 is connected to the oil passages 11 and 12 by a shuttle valve 17.

In this hydraulic winch device, when the hydraulic motor 1 is driven in a state where the second brake device 8 is braked by the foot brake pedal 9, hoisting and power lowering are performed.

That is, when the directional control valve 13 is switched to the normal rotation position by the operation lever 16, the main pump 1
4 supplies the oil pressure to the oil passage 11, and the oil pressure is supplied from the shuttle valve 17 to the hydraulic brake cylinder 6 to
Of the hydraulic motor 1
And the hydraulic motor 1 rotates forward and the winch drum 3
Rotates by winding.

When the directional control valve 13 is switched to the reverse rotation position by the operation lever 16, pressure oil is supplied to the oil passage 12, and the pressure oil is supplied from the shuttle valve 17 to the hydraulic brake cylinder 6 so that the first brake When the device 4 is released, the hydraulic motor 1 is supplied to the hydraulic motor 1 to rotate in the reverse direction, and the winch drum 3 is rotated down.

When the directional control valve 13 is switched to the neutral position by the operation lever 16, the counter balance valve 10
The holding state of the suspended load is maintained by the action of. At this time, when the depression of the foot brake pedal 9 is released,
The braking of the brake drum 7 by the second brake device 8 is released, and the suspended load falls by its own weight, that is, falls free.

[0008]

In such a conventional winch, braking during free fall is all performed by braking of the brake drum 7 by the second brake device 8, so that the heat generated on the brake surface of the brake drum 7 is generated. Is a problem. The heat generated on the brake surface reduces the braking effect due to the fade phenomenon caused by the high temperature of the brake surface, and if the brake surface is used continuously for a long time with the high temperature,
There is a possibility that damage such as wire scratches and thermal cracks may occur on the brake surface.

Since the second brake device 8 is operated by the foot brake pedal 9, the pedaling force corresponding to the required braking force of the brake drum 7 is required at the time of free fall braking. It is difficult to adjust the pedal depression amount for adjusting the acceleration of the vehicle, and skill is required.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the amount of heat generated on the brake surface of the brake drum, reduce the burden on the operator, facilitate the adjustment of the acceleration of the free fall by pedal operation, and further improve the winch drum during the free fall. It is an object of the present invention to provide a hydraulic winch device capable of limiting the maximum speed of the hydraulic winch to an appropriate value.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention relates to a hydraulic motor 1 and a planetary gear connected to an output shaft of the hydraulic motor 1 for reducing the rotation of the output shaft. A speed reduction mechanism 2, a winch drum 3 integrally connected to one of the ring gear 2 e and the carrier shaft 2 d of the planetary speed reduction mechanism 2, and a first brake for braking the input side of the planetary speed reduction mechanism 2.
, A brake drum 7 integrally connected to one of the ring gear 2e and the carrier shaft 2d separately from the winch drum 3, and a second brake device 8 for braking the brake drum 7. In the first state in which the first brake device 4 is released and the second brake device 8 is in the braking state, winding by the hydraulic motor 1 is performed, the first brake device 4 is braked, and the second brake 8 is released. The condition 2 applies to a hydraulic winch device in which free fall is performed. The above-mentioned problems are caused by the hydraulic load circuit 19 including the hydraulic pump 20 which is driven to rotate by the rotation of the brake drum 7, the hydraulic pump 20 and the brake drum 7
And a clutch 18 for selectively intermittently switching between the two. The hydraulic load circuit 19 may include a relief valve 22 or a variable relief valve 27 (FIG. 2) for providing a load resistance. In addition to the configuration described above, as shown in FIG. 2, a speed sensor 29 for detecting the rotation speed of the winch drum, and a variable relief valve 27 in accordance with the rotation speed of the winch drum 3 detected by the speed sensor 29.
A control device 28 for variably setting the relief pressure of the pressure sensor may be provided.

[0012]

The brake drum 7 rotates only at the time of free fall, and does not rotate at the time of hoisting and at the time of power drop. When the brake drum 7 rotates during the free fall, the hydraulic pump 20 is driven, and a load (rotational resistance) is applied to the brake drum 7, and the braking load of the second brake device 8 is reduced by the load. When there is no need to apply a hydraulic load to the brake drum 7 during free fall, the clutch 18
To separate the hydraulic pump 20 from the brake drum 7.
When it is necessary to apply a hydraulic load to the brake drum 7, the hydraulic pump 20 is connected to the brake drum 7 by the clutch 18.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used for easy understanding of the present invention. However, the present invention is not limited to this.

[0014]

FIG. 1 shows a first embodiment. In FIG. 1, the same parts as those in the above-described conventional example are denoted by the same reference numerals and described. In the first embodiment shown in FIG. 1, the clutch 1 is attached to a carrier shaft 2d which rotates integrally with the brake drum 7.
The hydraulic pump 20 of the hydraulic load circuit 19 is connected by 8. The hydraulic load circuit 19 includes an oil tank 21, a hydraulic pump 20, a relief valve 22, and an oil cooler 23. The hydraulic pump 20 is driven by the rotation of the brake drum 7, and sucks oil from the oil tank 21. The relief valve 22 is on the discharge side of the hydraulic pump 20 and applies load resistance to the hydraulic pump 20.

The clutch 18 is connected and disconnected by a clutch driving mechanism 24.
When the switch 5 is turned on, the clutch 18 is set to the connected state, and when the mode switch 25 is turned off, the clutch 18 is set to the disconnected state.

In this embodiment, when the mode switch 25 is turned on and a free fall is performed with the clutch 18 connected, the hydraulic pump 20 is rotated by the rotation of the brake drum 7. Since the discharge oil of the hydraulic pump 20 flows into the oil tank 21 through the relief valve 22 and the oil cooler 23, the pump discharge pressure rises to the relief pressure of the relief valve 22. As a result, a load (rotational resistance) is applied to the rotation of the brake drum 7 and further to the rotation of the winch drum 3, and the braking load on the brake drum 7 by the second brake device 8 during free fall is reduced by the load. The rotational energy of the brake drum 7 is converted into thermal energy by the hydraulic relief action of the relief valve 22 to increase the temperature of the oil in the hydraulic load circuit 19, but the oil is radiated and cooled by the oil cooler 23.

The torque Tp applied to the winch drum 3 by the hydraulic pump 20 is a torque (load torque) in the direction opposite to the torque (rope radius × rope tension) Tr generated on the winch drum 3 by a suspended load, and is expressed by the following equation. Is indicated by

Tp = (P · q / 2) (1 / η) where P: relief pressure of relief valve 22 q: displacement volume of hydraulic pump 20 η: pump efficiency of hydraulic pump 20

Assuming the braking torque Tb of the brake drum 7, the following equation is obtained.

## EQU2 ## As a result, the braking torque Tb of the brake drum 7 is reduced by the load torque Tp of the hydraulic pump 20, and the braking operation force of the brake drum 7 is reduced accordingly.

Assuming that the free fall distance is L, the potential energy of the suspended load is Tr × L, and the energy balance is given by the following equation.

Tr · L = (Tb + Tp) L Here, the energy represented by Tp × L is converted into thermal energy by the relief action of the relief valve 22, and the energy Tb × L for generating heat on the brake surface of the brake drum 7 is , Tb × L = Tr × L−Tp × L,
Heat generation energy is reduced by Tp × L as compared with the conventional hydraulic winch device, and overheating of the brake surface is avoided.

The clutch 18 selects whether the hydraulic load circuit 19 is operated or not. The clutch 18 is kept connected when the free fall load is constant and large as in the case of a clam-shull operation. On the other hand, when it is necessary to minimize the resistance torque at the time of free fall, as in the case of free fall with only the empty hook of the crane, the clutch 18 is disconnected to disconnect the hydraulic pump 20 from the brake drum 7.

FIG. 2 shows a second embodiment. In the second embodiment, an electromagnetic variable relief valve 27 using a proportional solenoid 26 is provided in the hydraulic load circuit 19 instead of the relief valve 22. The variable relief valve 27 variably sets the relief pressure by controlling the energization of the solenoid 26 by the control device 28. Also, winch drum 3
A speed sensor 29 for detecting the rotation speed of the motor. The control device 28 inputs the rotation speed of the winch drum 3 detected by the speed sensor 29, and changes the relief pressure of the variable relief valve 27 to a high pressure side when the rotation speed approaches a preset maximum speed limit. The value of the current supplied to the solenoid 26 is controlled.

With such a configuration, the winch drum 3
When the rotation speed of the vehicle approaches the preset maximum speed limit,
The relief pressure of the variable relief valve 27 becomes high, and the driving load of the hydraulic pump 20 increases accordingly. As a result, the acceleration at the time of the free fall is suppressed, and the rotation speed of the winch drum 3 is kept below the maximum speed limit.

For example, in FIG. 3, the output of the speed sensor 29 is input to one terminal of a comparator 31, and the variable power source 3 for setting a reference voltage is input to the other input terminal.
2 is input. When the rotation speed of the winch drum 3 exceeds the reference speed, the comparator 31 outputs a high-level signal, and puts the AND gate 33 in the immobilized state. Therefore, the AND gate 33 inputs the output voltage of the speed sensor 29 to the function generator 34. Function generator 34
Outputs a relief control voltage Vr proportional to the input voltage Vv, and the relief set pressure of the relief valve 27 is a speed sensor 29
It increases in proportion to the output of As a result, as the rotation speed of the winch drum 3 increases, a larger load is applied to the hydraulic load circuit 19.
And the maximum number of rotations of the winch drum 3 is limited.

FIG. 4 is a diagram showing the relationship between the relief set pressure of the variable relief valve 27 shown in FIG. 3 and the rotation speed of the winch drum 3. The constant relief set pressure is maintained up to the reference speed. , The relief set pressure increases and the rotational load increases.

Although the on / off state of the clutch 18 is switched by turning on and off the mode switch 25, even if the clutch 18 is disconnected, the clutch 18 is forcibly connected when the rotation speed of the winch drum 3 exceeds a reference value. However, the winch drum 3 may be prevented from undesirably increasing the rotation speed during the free fall.

In the above description, the winch in which the ring gear 2e is integrally connected to the winch drum 3 and the brake drum 7 is integrally connected to the carrier shaft 2d has been described. The present invention can be applied to a similar winch in which 2d is integrally connected to the winch drum 3.

[0027]

As described above in detail, according to the present invention, a load is applied to the rotation of the brake drum during the free fall by the driving load of the hydraulic pump, and the second brake is applied by the load. Since the braking load on the device is reduced, the amount of heat generated on the brake surface of the brake drum is reduced, fading is avoided, thermal damage to the brake drum is suppressed, and the durability of the brake drum is improved. I do. In addition, the reduction in the braking force that the second brake device bears reduces the pedal effort of the foot brake pedal that operates the second brake device,
The burden on the operator is reduced. Further, the acceleration of the free fall is reduced, the acceleration of the free fall is easily adjusted by operating the pedal, and a braking operation with a good feeling can be easily obtained. Furthermore, by setting the relief pressure of the variable relief valve variably according to the rotation speed of the winch drum detected by the speed sensor, the maximum speed of the winch drum during free fall is limited to an appropriate value, improving safety. I do.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a hydraulic winch device according to the present invention.

FIG. 2 is an overall configuration diagram showing a second embodiment of the hydraulic winch device according to the present invention.

FIG. 3 is a block diagram illustrating an example of a control device 28 according to a second embodiment.

FIG. 4 is a graph showing a relationship between a rotation speed and a relief set pressure according to a second embodiment.

FIG. 5 is an overall configuration diagram of a conventional hydraulic winch device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2 Planetary reduction mechanism 3 Winch drum 4 First brake device 6 Hydraulic brake cylinder 7 Brake drum 8 Second brake device 9 Foot brake pedal 13 Direction switching valve 14 Main pump 17 Shuttle valve 18 Clutch 19 Hydraulic load circuit 20 Hydraulic pump 22 Relief valve 25 Mode switch 27 Variable relief valve 28 Control device 29 Speed sensor

Claims (4)

(57) [Claims] 1. A hydraulic motor, a planetary reduction mechanism connected to an output shaft of the hydraulic motor to reduce the rotation of the output shaft, and integrally connected to one of a ring gear and a carrier shaft of the planetary reduction mechanism. A winch drum, a first brake device for braking an input side of the planetary reduction mechanism, a brake drum integrally connected to one of the ring gear and a carrier shaft separate from the winch drum, and the brake drum A second brake device that brakes the first brake device, wherein the first brake device is released, and in the first state of braking of the second brake device, winding by the hydraulic motor is performed, and the first brake device is Is braking, the second
In hydraulic winch device free fall is performed brakes in the second state of the release, and hydraulic load circuit including a hydraulic pump rotationally driven by the rotation of the brake drum, wherein said hydraulic pump blur
A hydraulic winch device comprising: a clutch for selectively intermittently connecting and disconnecting a hydraulic drum . 2. The hydraulic winch device according to claim 1, wherein the hydraulic load circuit includes a relief valve for applying a load resistance. 3. The hydraulic winch device according to claim 1, wherein the hydraulic load circuit includes a variable relief valve for applying a load resistance. 4. A speed sensor for detecting a rotation speed of the winch drum, and a control device for variably setting a relief pressure of the variable relief valve according to a rotation speed of the winch drum detected by the speed sensor. The hydraulic winch device according to claim 3, wherein: