JPH0331656Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a brake device, and more particularly, to an automatic brake device for preventing self-propulsion of a hydraulic actuator that drives a winch or the like.

(Prior Art) Some conventional hydraulic circuits and brake devices for hydraulic actuators that drive winches and the like are constructed as shown in FIG. That is, in the figure, hydraulic fluid supplied from a hydraulic pressure source 1 is sent to a hydraulic motor 3 via a three-position switching valve 2, and the rotation of the hydraulic motor 3 at this time rotationally drives a drag 4 connected thereto. Then, the rope 5 is wound and unwound around the drag 4 to raise and lower the load 7. Further, the pressure fluid supplied to the hydraulic motor 3 is sent to the brake control cylinder device 9 via the high pressure selection valve 8, and the piston 13 connected to the brake band 12 wrapped around the brake drum 10 moves. This releases the brake on the drum 4, allowing the hydraulic motor 3 to rotate the drum 4 as described above.

(Problem to be solved by the present invention) However, in the conventional brake device as described above, the hydraulic power source 1 is connected via the three-position switching valve 2.
Initially, the hydraulic fluid supplied from the brake control cylinder device 9 is sent into the brake control cylinder device 9 and used to move the piston 13, but the driving pressure of the hydraulic motor 3 at the start of winch operation is equal to the operation end pressure of the brake control cylinder device 9. Since the hydraulic pressure is set higher, as shown in FIGS. 6c to 6e, when the piston 13 completes its full stroke, the hydraulic pressure increases rapidly, and the pressurized liquid changes its destination and flows into the hydraulic motor 3. Therefore, the hydraulic motor 3 suddenly starts rotating, and the load 7 suddenly starts moving up or down. This phenomenon occurs when the load is light during hoisting, and when the drive pressure of the hydraulic motor 3 is lowered by the counterbalance valve 19.
is set, so it occurs regardless of the size of the load. For this reason, it is not possible to gradually increase the initial rotational speed of the hydraulic motor 3 from zero, and the ascending speed or descending speed of the cargo 7 must be finely adjusted from zero and gradually increased to the desired speed. I was unable to perform the operation of going.

(Purpose of the invention) Therefore, the present invention aims to operate the hydraulic actuator by gradually increasing the hydraulic pressure in the liquid supply path of the hydraulic actuator from the hydraulic pressure required for operating the hydraulic actuator. The purpose is to be able to gradually increase the speed from zero, and to make fine adjustments to the ascending speed or descending speed of the load 7 from the initial zero, and to gradually increase the speed to a desired speed. .

(Structure of the invention) The braking device according to the invention prevents a hydraulic actuator from self-propelling, and includes a braking means capable of braking an output part of the hydraulic actuator, and a braking means connected to the braking means to control the output part. a brake control cylinder device that controls a braking means to apply and release the brake; and a brake release pressure introduction path that connects the liquid supply path of the hydraulic actuator and the brake control cylinder device; A hydraulic pressure transmitting means and a throttle means are provided in parallel in the middle of the path, and when pressure fluid is introduced into the brake release pressure introduction path, the hydraulic pressure transmitting means has a volume smaller than the maximum liquid suction volume of the brake control cylinder device. The structure is configured to send liquid to a brake control cylinder device.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a diagram showing a brake device according to an embodiment of the present invention. The same members as before are given the same reference numerals.

In FIG. 1, a three-position switching valve 2 is arranged in a hydraulic circuit 15 between a hydraulic pressure source 1 and a hydraulic motor (hydraulic actuator) 3, and this three-position switching valve 2 is connected to a manual lever 6. The stop position 2a, the winding position 2b, and the winding down position 2c are operated by the
It can be switched to either position. hydraulic motor 3
is connected to the drum (output part) 4 of the winch, and around this drum 4 is a rope 5 for lifting loads.
is wrapped around it so that the luggage 7 can be hung from it. The hydraulic circuit 15 has two liquid passages 15a and 15b, upper and lower in the drawing, which alternately become liquid supply passages by switching operation of the three-position switching valve 2. A counterbalance valve 19 is provided in the middle of the liquid path 15b, and when the pressure in the liquid path 15a exceeds the set pressure via the pilot path 20, the liquid path 15b is directed from the hydraulic motor 3 side to the three-position switching valve 2 side. Allow liquid to flow once. Also,
A check valve 21 is provided in the liquid path 15b in parallel with the counterbalance valve 19, and always allows liquid to flow from the three-position switching valve 2 side toward the hydraulic motor 3 side. The no-load hoisting pressure of the hydraulic motor 3 is set to 15 to 20 kg/cm ² by the check valve 21, etc.
In addition, the load hoisting pressure is set to 15 to 20 kg/cm ² by a counterbalance valve 19, respectively. A safety valve 16 is provided between the hydraulic pressure source 1 and the three-position switching valve 2, and when the discharge pressure of the hydraulic pressure source 1 exceeds a predetermined pressure, the pressure liquid is discharged to prevent damage to the hydraulic circuit 15. . A brake drum 10 is integrally provided on the drum 4, and by wrapping and tightening a brake band 12 around the circumferential surface of the brake drum 10, rotation of the drum 4 can be braked. The brake drum 10 and the brake band 12 constitute braking means. The brake band 12 is connected to a piston 13 of the brake control cylinder device 9, and when the piston 13 is urged leftward in the figure by a spring 11, the brake band 1
When a clamping force is applied to 2 and pressure fluid is sent into the cylinder 14, the piston 13 is moved by the spring 11.
It overcomes the biasing force and moves to the right in the figure, reducing the tightening force on the brake band 12. piston 1
3. The cylinder 14 and the spring 11 constitute a brake control cylinder device 9. The operating pressure of the brake control cylinder device 9 is 5 kg/kg at the beginning of operation.
cm ² , and is set at approximately 10Kg/cm ² at the end of operation (at full stroke). The hydraulic circuit 15 and the cylinder 14 communicate with each other through a brake release pressure introduction path 18, and a high pressure selection valve 8 is provided in the middle of this brake release pressure introduction path 18.
is provided, and even if either of the upper and lower liquid passages 15a, 15b of the hydraulic pressure circuit 15 becomes a liquid supply passage, the high pressure selection valve 8 allows the liquid supply passage to communicate with the cylinder 14. There is. In the middle of the brake release pressure introduction path 18 between the high pressure selection valve 8 and the cylinder 14, a hydraulic pressure transmission means 23 and a throttle means 2 are provided.
4 are provided in parallel. Further, a check valve 25 is provided in parallel with the hydraulic pressure transmitting means 23 and the throttling means 24, and a throttling means 26 is arranged in series with the check valve 25. As shown in FIG. 3, the hydraulic pressure transmission means 23 includes a cylinder 28,
It has a piston 29 and a spring 30, and if the hydraulic pressure on the left side of the piston 29 in the figure increases even slightly from the right side, the piston 29 easily moves to the right side in the figure, and the maximum liquid suction volume of the brake control cylinder device 9 increases. The throttle means 24, which can deliver a small volume of liquid into the cylinder 14 of the brake control cylinder device 9, is constituted by a throttle hole 24 as shown in FIG.
has a valve seat 35, a sphere 36, and a spring 37, and the throttle means 26 is for adjusting the timing when the piston 13 returns, and the check valve 25
It is formed by the gap between the valve seat 35 and the sphere 36 when they are separated from each other by opening. This valve seat 3
The cross-sectional area of the gap between 5 and the sphere 36 is larger than the cross-sectional area of the throttle hole 24 and smaller than the cross-sectional area of the brake release pressure introduction path 18.

Next, the effect will be explained. Here, for convenience of explanation, it is assumed that the cargo 7 has a light load that can be ignored compared to the no-load hoisting pressure. As shown in FIG. 1, when the stop position 2a of the three-position switching valve 2 is located in the middle of the hydraulic circuit 15, the hydraulic fluid discharged from the hydraulic pressure source 1 is not sent to the hydraulic motor 3. The liquid is discharged into the liquid tank 40. Next, when the manual lever 6 is used to gradually position the hoisting position 2b of the three-position switching valve 2 to the middle of the hydraulic circuit 15 as shown in FIG. 15b and passes through the check valve 21 to the hydraulic motor 3. On the other hand, the pressurized liquid in the liquid path 15b is introduced into the brake release pressure introduction path 18, and further flows into the pilot path 44 to push the high pressure selection valve 8 downward in FIG. 1 to switch it. Therefore, the pressure fluid in the brake release pressure introduction path 18 passes through the opening 8 of the high pressure selection valve 8 to the hydraulic pressure transmission means 2.
3, the hydraulic pressure acts on the left end surface of the piston 29 in FIG. 3, and the piston 29 easily moves to the right in the figure, and then comes into contact with the cylinder stepped portion 28a and stops. At this time, the hydraulic pressure corresponding to the volume by which the piston 29 has moved is discharged from the cylinder 28 and sent into the cylinder 14 of the brake control cylinder device 9. At this time, the liquid volume releases the braking force of the brake control cylinder device 9. The brake drum 10 can rotate without resistance from the brake band 12, but at this time, the hydraulic pressure in the liquid path 15b has not yet reached the no-load hoisting pressure of the hydraulic motor 3, so the hydraulic motor 3 does not rotate. . Note that it is the brake band 12 that provides the piston 13 of the brake control cylinder device 9 with a predetermined stroke.
This is because wear, deformation, etc. will occur. Thereafter, as shown in FIG. 5b, the liquid flow rate in the liquid path 15b gradually increases, and the brake release pressure introducing path 18
The pressure liquid inside flows into the cylinder 14 through the throttle hole 24, and gradually moves the piston 13 as shown in FIG. 5c. At this time, the fluid pressure in the brake release pressure introduction path 18 gradually increases due to the flow resistance of the throttle hole 24, and at the same time, the fluid pressure in the fluid path 15b serving as the liquid supply path also increases as shown in FIG. 5d. It gradually rises from zero. When this hydraulic pressure reaches the no-load hoisting pressure (approximately 15 to 20 Kg/cm ² ) of the hydraulic motor 3, the hydraulic motor 3 starts rotating, and the liquid in the liquid path 15b is removed as shown in Fig. 5e. As the pressure increases, the rotation speed gradually increases. Therefore, the rotational speed of the winch drum 4 can be gradually increased from zero, and the lifting speed of the load 7 can be finely adjusted from zero initially through the rope 5 to gradually increase it to the desired speed. be able to. Brake control cylinder device 9
When the piston 13 makes a full stroke, the pressure fluid that had been flowing into the cylinder 14 will now flow into the fluid path 15b, and the amount of pressure fluid supplied to the hydraulic motor 3 will increase slightly, but the rotation of the hydraulic motor 3 will increase. number is 5th
As shown in Figure e, it only rises slightly, but unlike the conventional case, it does not rise sharply and obstruct fine adjustment. When stopping the cargo 7 at a predetermined height, the three-position switching valve 2 is manually returned to the stop position using the lever 6. The cargo 7 is stopped by the action of the check valve 21 to prevent liquid from flowing back. At the same time, the high pressure selection valve 8 goes to the neutral position, so that the brake release pressure introduction path 18 on the left side in the figure is communicated with the liquid tank 41 by the hydraulic pressure transmission means 23, etc., and the internal hydraulic pressure becomes atmospheric pressure. decreases to. Therefore, the liquid in the cylinder 14 of the brake control cylinder device 9 is transferred to the piston 13.
The fluid is pushed out by the biasing force of the spring 11 through the check valve 25 and the throttling means 24 and 26, and is discharged into the liquid tank 41. At this time, the brake band 1 connected to the piston 13
A clamping force is applied to the hydraulic motor 2 to brake the brake drum 10, thereby preventing self-propelling due to internal leakage of the counterbalance valve 19 of the hydraulic motor 3 due to the load of the cargo 7.

When lowering the cargo 7, the three-position switching valve 2 is positioned at the lowering position 2c. At this time, the hydraulic pressure transmission means 23, the throttle hole 24, and the brake control cylinder device 9 operate in the same manner as in the case of winding up.

These hoisting and hoisting operations are shown in Figure 7a.
Even if the manual lever 6 is used suddenly as shown in FIG. Hoisting and lowering operations can be performed without interference. Also,
In the embodiment described above, when the hydraulic motor 3 is stopped and braked, the liquid discharged from the cylinder 14 of the brake control cylinder device 9 is passed through the check valve 25 and the throttle means 2.
6 and the high pressure selection valve 8 to the liquid tank 41. However, a liquid path that directly communicates the cylinder 14 and the liquid tank and a valve are provided in the middle, and this valve is connected to the three-position switching valve 2 at the stop position. Alternatively, the cylinder 14 may be linked to open when the cylinder 14 becomes dry, and the liquid may be discharged directly from the cylinder 14 to the liquid tank. Further, the braking means may directly brake the hydraulic motor 3, which was adapted to brake the drum 4 in the embodiment described above. Further, in the above embodiment, the hydraulic motor 3 that outputs rotational motion was used as the hydraulic actuator, but a brake device that uses a hydraulic actuator such as a cylinder and piston that outputs reciprocating motion may also be used. . Therefore,
It may also be a brake device that can be applied to operations other than winching.

(Effects of the invention) As explained above, according to the invention, the operating speed of the hydraulic actuator is gradually increased from zero, and the ascending speed or descending speed of the cargo is finely adjusted from zero initially to gradually reach the desired value. It can be increased up to speed.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing a brake device according to an embodiment of the present invention, FIG. 2 is an overall configuration diagram showing a conventional brake device, and FIG. 3 is an enlarged detailed cross-section of the hydraulic pressure transmission means 23 of FIG. 1. 4 is an enlarged detailed sectional view of the throttle means 24, check valve 25 and throttle means 26 shown in FIG. 3, FIGS. 5 and 7 are of the brake device shown in FIG. 1, and FIG. These are graphs showing the characteristics of the brake device with respect to time, and FIGS.
Figure b is the liquid flow rate in the hydraulic circuit, Figures 5c, 6c, and 7c are the stroke amounts of the piston of the brake control cylinder device, Figures 5d, 6d, and 7.
FIG. d is a graph showing the liquid pressure in the liquid supply path, and FIGS. 5e, 6e, and 7e are graphs showing changes in the rotational speed of the hydraulic motor over time. 3...Hydraulic motor (hydraulic actuator), 4
... Drum (output part), 9 ... Brake control cylinder device, 10 ... Brake drum, 12 ... Brake band, 15 ... Hydraulic pressure circuit (liquid supply path),
18... Brake release pressure introduction path, 23... Hydraulic pressure transmission means, 24... Throttle hole (throttle means).

Claims (1)

[Scope of utility model registration request] a brake means capable of braking an output section of the hydraulic actuator; a brake control cylinder device connected to the brake means and controlling the brake means to brake and release the output section; a liquid supply path for the hydraulic actuator; In an automatic braking device for preventing self-propulsion of a hydraulic actuator, the brake release pressure introduction path is connected to a brake control cylinder device. provided in parallel, and when pressure fluid is introduced into the brake release pressure introduction path, the hydraulic pressure transmission means sends a volume of liquid smaller than the maximum liquid suction volume of the brake brake cylinder device to the brake control cylinder device. brake equipment.