JPH042915Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a brake control device for a winch.

(Prior Art) As a conventional winch brake control device, those shown in FIGS. 3 to 5 are known.

The device shown in FIG. 3 performs position control using a hydrostatic system, and when a brake pedal 51 is operated, a master cylinder 5 connected to a supply tank 52 is operated.
3, pressure oil is guided from the master cylinder 53 to the wheel cylinder 55 via the brake line 54, and the brake band 56 is actuated to close the hoisting drum 5.
It is designed to brake 7. With this device,
Since the position of the wheel cylinder 55 is controlled according to the amount of depression of the brake pedal 51, the operator can directly feel the contact state between the brake band 56 and the hoisting drum 57 as a reaction force with his or her feet. Therefore, although it has the advantage of allowing delicate operations, it requires a large amount of pedal effort. Note that if the brake pedal 51 is made longer, the pressing force can be reduced;
The longer the pedal stroke becomes, the more fatigue the operator will experience. Further, since the amount of oil discharged from the master cylinder 53 is limited, it is not possible to follow the wear of the brake band 56 and the like, and it is necessary to frequently adjust the tension of the brake band 56.

The device shown in FIG. 4 controls pressure using a hydrodynamic system, and when the brake pedal 51 is depressed,
A hydraulic pump 59 is connected to the primary pipe line 58 to introduce secondary pressure to the secondary side of the pressure reducing valve 60, and the secondary pressure is passed through the brake pipe line 54 to the wheel cylinder 5.
5, the wheel cylinder 55 and the brake band 56 are operated, the secondary pressure of the pressure reducing valve 60 is controlled in proportion to the amount of pedal depression, and the operation of the wheel cylinder 55 is pressure-controlled by the secondary pressure. . With this device, since the operator only needs to operate the pressure reducing valve 60 with the brake pedal 51, the pedaling force can be reduced, and the pressure reducing valve 60 can be operated with less force.
The discharge oil amount of 0 is the pump 5 connected to its primary side.
9, so even if the brake band 56 etc. are worn out, the wheel cylinder 55 can be extended according to the amount of wear, and the brake can be reliably operated. The operator cannot feel the contact state of 57 with his or her feet. Therefore, it is difficult for the operator to adjust the amount of depression of the brake pedal 51 and the braking force, and it is difficult to lower the suspended load slightly or at a constant speed. Moreover, in the pressure control method, if the pump 59 on the primary side of the pressure reducing valve 60 fails, pressure cannot be derived to the secondary side, making it impossible to control the brake.

The device shown in FIG. 5 performs position control and pressure control using a combination of hydrostatic and hydrodynamic methods. A hydraulic pump 59 is connected to the suction side pipe line 62 of the master cylinder 61, and the hydraulic pump 59 is connected to the suction side pipe line 62 of the master cylinder 61, and the The brake line 54 is connected via a check valve 63, and a relief valve 64 is provided between the brake line 54 and the suction side line 62.
Position control is performed to control the wheel cylinder 55 by guiding pressure corresponding to the amount of movement of the brake pedal 51 to the brake pipe 54, and at the final depression position of the brake pedal 51, pressure oil from the hydraulic pump 59 is guided to the brake pipe 54. The pressure of the wheel cylinder 55 is controlled. With this device, when the load is light, the brake reaction force can be felt with the foot, similar to the position control method shown in Figure 3, to improve operability, but when the load is heavy, the brake force is controlled by the pump pressure. There are problems such as a large pedal force is required to apply the brake force, and delicate control is difficult when the brake force is large.

(Purpose of the invention) The present invention was made to solve these conventional problems.It reduces the pedal force to reduce operator fatigue, and also improves the contact state between the brake band and the hoisting drum. Winch brake control that can be controlled accurately, allows the operator to easily feel the contact state with their feet, and allows for easy control of slight and constant descent, improving operability, workability, and safety. It provides equipment.

(Structure of the invention) The invention includes a wheel cylinder that brakes a hoisting drum, a servo valve that controls supply and discharge of pressure oil to and from the wheel cylinder, and a brake pedal that operates the servo valve. , a spool operated by a brake pedal, and a sleeve whose position is controlled by following the movement of the spool, a hydraulic power source is connected to the input port, and the above-mentioned pressure source is connected to the output port via the brake pipe. A wheel cylinder is connected thereto, and an amount of oil corresponding to the amount of movement of the sleeve is discharged from an output port and guided to the wheel cylinder.

With this configuration, the wheel cylinder is precisely controlled by the position control method using the servo valve, making it easy to perform slight and constant descent.The brake force acts as a reaction force on the spool of the servo valve, and this reaction force is transferred by the operator's foot. In addition, the sleeve is operated in accordance with the movement of the spool to determine the amount of oil discharged from the servo valve and control the braking force, reducing the pedal effort and reducing operator fatigue.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention. In Figure 1, 1 is a hydraulic pump, 2 is a pipeline, 3 is a servo valve, 4 is a brake pipeline, 5 is a wheel cylinder, 6 is a brake band, 7 is a hoisting drum, 8 is a return oil pipeline, and 9 is a tank. , 10 is a brake pedal. Servo valve 3 is brake pedal 1
0 and a sleeve 1 whose position is controlled by following the movement of the spool 11.
2, the hydraulic pump 1 is connected to the input port 13 via the conduit 2, the wheel cylinder 5 is connected to the output port 14 via the brake conduit 4, and the conduit 8 is connected to the tank port 15. A tank 9 is connected thereto. According to the amount of depression of the pedal 10, the spool 11 is moved, and the pressure oil from the hydraulic pump 1 is guided to the first oil chamber 16, and the sleeve 12 is moved following the movement of the spool 11. An amount of oil corresponding to the amount of movement of the sleeve 12 is discharged from the second oil chamber 17 to the output port 14 and guided to the wheel cylinder 5 via the pipe 4, thereby extending the wheel cylinder 5 and causing the brake band 6 to extend. is pressed against the hoisting drum 7, so that the hoisting drum 7 is braked.
18 is a check valve.

Next, the specific structure of the servo valve 3 will be explained with reference to FIG. This servo valve 3 has a spool 11 and a sleeve 12 provided in a valve body 20 so as to be able to slide freely relative to each other in the axial direction.
0 is provided with an input port 13, an output port 14, and a tank port 15, a first oil chamber 16 is formed at one end of the sleeve 12, and a second oil chamber 17 communicating with the output port 14 is formed at the other end. It is formed. The sleeve 12 is biased toward the left in the drawing by a neutral return spring 21 provided in the second oil chamber 17, and a stopper 23 provided in the lid member 22
is held in the position shown (neutral).
In this sleeve 12, a spring chamber 25 is formed on the distal end side of the spool 11 via a plug 24, and the spool 11 is biased toward the left in the drawing by a neutral return spring 26 provided in the spring chamber 25.
It is held in the illustrated position (neutral) by a stopper ring 27 attached to the sleeve 12.

The spool 11 has axial holes 31, 33,
35 and radial holes 32 and 34 are provided to communicate with each other, and the spring chamber 25 and the first oil chamber 16 are constantly communicated with each other through these holes 31 to 35. In addition, a first
and second circumferential grooves 36 and 37 are provided, and the first circumferential groove 3
6 is constantly communicated with the input port 13 via a passage 38 provided in the sleeve 12 and a passage 39 provided in the valve body 20, and the second circumferential groove 37 is connected to a radial hole 40 provided in the sleeve 12. The spool 11 is constantly communicated with the tank port 15 through a passage 41 formed on the outer periphery of the sleeve and passages 42, 43, and 44 provided on the valve body pair 20, and the spool 11 The holes 32 are selectively communicated. A check valve 18 is provided between the second oil chamber 17 and the tank port 15, and a locking portion 45 for opening the check valve 18 is provided at the tip of the sleeve 12. 46 is a spring.

For the servo valve 3, as shown in FIG. 1, a hydraulic pump 1 is connected to an input port 13 via a pipe line 2, and a wheel cylinder 5 is connected to an output port 14 via a pipe line 4. Spool 11
A brake pedal 10 is connected to the input member 19 via an input member 19.

Next, the effect will be explained.

First, when the brake pedal 10 is in the neutral position, the second
As shown in the figure, the first circumferential groove 36 of the sleeve 12 of the servo valve 3 is blocked by the spool 11, and the hole 32 of the spool 11 communicates with the second circumferential groove 37. As a result, the first oil chamber 16 and the spring chamber 25 are communicated with the tank port 15, and the first oil chamber 16 and the spring chamber 25 are communicated with the tank port 15.
The pressure inside the oil chamber 16 becomes tank pressure, and the sleeve 12 and spool 11 are connected to the spring 26,
21 in the illustrated position (neutral). In addition, the check valve 18 is opened by the end locking portion 45 of the sleeve 12, the second oil chamber 17 is communicated with the tank port 15, and the wheel cylinder 5 connected to the output port 14 is also communicated with the tank 9. and the brake is released.

Next, when the brake pedal 10 is depressed, the spool 11 of the servo valve 3 is moved to the right in the drawing, the second circumferential groove 37 is blocked by this spool 11, and the hole 32 of the spool 11 is It communicates with the circumferential groove 36. This allows input port 13
Pressure oil from the hydraulic pump 1 is led to the first oil chamber 16 at one end of the sleeve 12, and the pressure oil moves the sleeve 12 rightward in the drawing against the spring 21. Due to this movement of the sleeve 12, the locking portion 45 at the tip of the sleeve locks the check valve 18.
The check valve 18 is closed by the spring 46, and the communication between the second oil chamber 17 and the tank port 15 is cut off.Then, the oil in the second oil chamber 17 is discharged from the output port 14, and the pressure oil is is guided to the wheel cylinder 5 via the pipe 4 in FIG. Ru.

In this case, the sleeve 12 moves following the movement of the spool 11, and the sleeve 12 moves by an amount corresponding to the amount of movement of the spool 11, and then the first circumferential groove 36 of the sleeve 12 is closed, The second circumferential groove 37 communicates with the hole 32, the first oil chamber 16 communicates with the tank port 15, that is, the tank 9, the pressure in the oil chamber 16 becomes the tank pressure, and the movement of the sleeve 12 is stopped. In this way, position control is performed in which the amount of movement of the spool 11 and the amount of movement of the sleeve 12 are determined according to the amount of operation of the brake pedal 10, and the volume of the second oil chamber 17, the amount of oil discharged from the output port 14, and the wheel The amount of extension of the cylinder 5 is determined, the amount of pressure of the brake band 6 against the hoisting drum 7 is determined, and the braking force is controlled. Therefore, by reducing the amount of operation of the brake pedal 10,
By reducing the above pressure contact amount and performing braking with a half brake, the hanging load can be lowered slightly and at a constant speed.

During the above half braking, the hoisting drum 7
is rotated in the downward direction by the load of the suspended load, and the brake band 6 is wound around the circumferential surface of the hoisting drum 7 due to the friction between the brake band 6 and the hoisting drum 7, and the band 6 and The amount of pressure contact with the hoisting drum 7 increases, and accordingly, the wheel cylinder 5 is extended from the initial stage of its operation.

In this case, if the conventional pressure control method uses a pressure reducing valve as described above, pressure oil will flow from the pressure reducing valve following the expansion of the wheel cylinder, and the pressure in the wheel cylinder will be maintained at the pressure determined by the brake pedal. Since the pressure reducing valve operates to maintain the pressure, the braking force (pressure x contact area) will eventually become larger than it was at the beginning of operation. Therefore, reduce the operating angle of the brake pedal to reduce the braking force of the hoisting drum. However, the braking force increases automatically and the hoisting drum is immediately braked, making it difficult to lower the suspended load slightly or at a constant speed.

However, if the servo valve 3 is used as in the present invention, the position of the sleeve 12 is determined by the brake pedal 10, and the amount of oil discharged from the servo valve 3 is determined. 7 rotates in the downward direction and the cylinder 5 is extended, the pressure in the brake line 4 is maintained at a low pressure, and the brake band 6 and hoisting drum 7 slip with half braking, causing the suspended load to is slowly lowered. Therefore, by slightly operating the brake pedal 10 to stop the hoisting drum 7, the hoisting drum 7 is braked with a half brake, and the suspended load can be lowered slightly or at a constant speed. Thereafter, when the brake pedal 10 is further depressed, the amount of oil discharged from the servo valve 3 is increased, the extension amount and pressure of the wheel cylinder 5 are increased, the braking force is increased, and the hoisting drum 7 is immediately and Braking is ensured.

In addition, in the above brake operation, the hoisting drum 7 of the brake band 6 by the wheel cylinder 5
The pressure contact force, that is, the braking force, is fed back to the reaction force and the brake pedal 10 via the sleeve 12 and spool 11 of the servo valve 3, so that the operator can feel the braking force with his or her feet. Moreover, the pressure oil introduced from the input port 13 is guided to the first oil chamber 16 at one end of the sleeve 12, and the sleeve 12 is moved to follow the movement of the spool 11, thereby performing the above control.
The pedal force can be reduced and operability can be improved.

Note that if the hydraulic pump 1 breaks down and pressure oil is no longer guided to the first oil chamber 16, the operating force (depression force) on the servo valve 3 increases, but the brake pedal 10
If you press hard, spool 11 and sleeve 1
2 can be mechanically moved to discharge oil from the second oil chamber 17, so the brake can be controlled.

Next, when the depression force on the brake pedal 10 is released, the spool 11 is returned to the neutral position by the spring 26, and the hole 32 is communicated with the second circumferential groove 37, and the spool 11 is returned to the neutral position by the spring 26.
The oil in the oil chamber 16 is discharged from the tank port 15 to the tank 9, and the sleeve 12 is returned to the neutral position by the spring 21. At the same time, the check valve 18 is opened by the locking part 45 at the tip of the sleeve, and the inside of the wheel cylinder 5 is opened. of oil flows from the second oil chamber 17 to the check valve 1.
8 and tank port 15 to the tank 9, the wheel cylinder 5 is retracted and the brake is released. At this time, the hoisting drum 7 is rotationally driven by the operation of the clutch or the like, and the hoisting drum 7 is freely lowered by turning off the clutch or the like.

In this way, when the pedal 10 is in the neutral position, the check valve 1
By opening 8 and communicating the second oil chamber 17 and the wheel cylinder 5 with the tank 9, the clearance between the hoisting drum 7 and the brake band 6 will be slightly fluctuated due to thermal expansion of the hoisting drum 7, etc. Even in such a case, the brake can be reliably released by putting the pedal in the neutral position, and the hoisting drum 7 can be driven or freely lowered. Further, even if the brake band 6 wears out, the brake can be accurately controlled by position control using the servo valve 3.

(Effects of the invention) As described above, the invention controls the stroke of the wheel cylinder by controlling the position of the servo valve,
It controls the brakes, allowing the operator to easily feel the operating status of the brakes with their feet, improving operability, allowing accurate control of braking force, and facilitating slight descents and constant-velocity descents using half brakes. Therefore, work efficiency can be improved. Furthermore, even if the hydraulic power source fails, the brakes can be controlled, improving safety.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention, FIG. 2 is a sectional view of a servo valve, and FIGS. 3 to 5 are hydraulic circuit diagrams showing conventional examples. 1... Hydraulic pump, 3... Servo valve, 5... Wheel cylinder, 6... Brake band, 7...
Hoisting drum, 10... Brake pedal, 11...
Spool, 12... Sleeve, 13... Input port, 14... Output port, 15... Tank port, 16... First oil chamber, 17... Second oil chamber, 18
...Check valve.

Claims (1)

[Scope of utility model registration request] It is equipped with a wheel cylinder that brakes the hoisting drum, a servo valve that controls supply and discharge of pressure oil to and from the wheel cylinder, and a brake pedal that operates the servo valve, and the servo valve is operated by the brake pedal. It is equipped with a spool and a sleeve whose position is controlled by following the movement of the spool, a hydraulic power source is connected to the input port, the wheel cylinder is connected to the output port via a brake pipe, and the sleeve is connected to the input port through a brake pipe. A brake control device for a winch, characterized in that an amount of oil corresponding to the amount of movement is discharged from an output port and guided to a wheel cylinder.