JPS644791Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a hydraulic brake device that allows fine adjustment of braking force.

[Prior art]

For example, a negative brake that releases the brake action when hydraulic pressure is applied is normally used in the crane vehicle swing mechanism of construction machinery. However, in this case, in order to fine-tune the braking action, in addition to the piston and spring for the negative brake, a piston and spring for the positive brake, which applies pressure to weaken the braking action, was added. Therefore, the size of the hydraulic brake device becomes large, and in some cases, it becomes impossible to install it, and the cost increases.

[Purpose of invention]

The present invention eliminates these drawbacks, and its purpose is to provide a hydraulic brake device that has a simple mechanism, reduces costs, and allows fine adjustment of the brake in the same way as when a positive brake is provided. There is a particular thing.

[Key points of the idea]

The brake device of the present invention is a hydraulic brake device in which the brake is released when pressure oil is supplied to the brake fluid chamber. a main body having a diameter hole, and an axial hole that is slidably inserted into the medium diameter or small diameter hole of the main body and communicates with the hole on the side facing the fluid supply hole of the main body, and on the opposite side between the pressure reducing spool and the differential piston, which is slidably inserted into the main body or across large and small diameter holes, and has a hole that communicates both ends. a decompression spring that presses the decompression spool toward the fluid supply hole of the main body; and a decompression spring that contacts the lid of the main body on one side and the differential piston on the other side and presses the differential piston toward the decompression spool. It is characterized by comprising a deflection spring and a pilot valve that supplies control hydraulic pressure to the stepped portions of medium and large diameters, large and small diameters of the differential piston.

[Example of idea]

The present invention will be explained below with reference to FIG. 1 showing one embodiment. A driven body 11 having a large inertia is fixed to an output shaft 13 of a hydraulic motor 12, and oil discharged from a pump 14 is supplied through a switching valve 15 so that the driven body 11 can be rotated in both directions. The cylinder 17 of the brake mechanism 16 is connected to the output shaft 13.
A compression spring 19 is in contact with the piston of the shoe 18, and in the state shown in the figure, the shoe 18 is pressed by the spring 19 and brakes the driven body 11.

A fluid supply hole 23, a small diameter hole 24, a medium diameter hole 25, and a large diameter hole 26 are sequentially opened in the main body 22 of the pressure reducing valve 21 from the tip (left side in the figure).
A fluid supply hole 28 and a rearwardly directed orifice 29 communicating with the hole 28 are provided at the tip of the vacuum spool 27 which is slidably inserted into the medium diameter hole 25 . A differential piston 30 is slidably inserted at the rear of the decompression spool 27, spanning the large and medium holes 25 and 26 and having a hole in the center that communicates both ends, and has a hole 31 at the rear end of the hole 26. Lid 3
2 is screwed onto the main body 22. Further, a pressure reducing spring 33 is disposed between the pressure reducing spool 27 and the differential piston 30, and a pressure reducing spring 33 is arranged between the differential piston 32 and the lid 3.
A deflection spring 34 is arranged between the two. Therefore, the pressure reducing spool 27 and the differential piston are pushed forward, and in the state shown in the figure, the front end of the pressure reducing piston 27 touches the shoulders of the small and medium holes 24 and 25, and the shoulder of the step of the differential piston 30 is medium-sized hole 25
and 26's shoulders. Note that the deflection spring 3
The strength of the spring 4 is greater than that of the decompression spring 33.

A hole 41 is formed in the main body 22 at a position relative to the pressure reducing spool 27, and this hole 41 is connected to a tank 43 or a pilot pump 44 via a switching valve 42. When the hole 41 is connected to the pilot pump 44, the oil discharged from the pump 44 flows from the hole 41 to the groove 45 provided on the outer periphery of the vacuum spool 27 and the hole 4.
6 and is supplied to the front of the vacuum spool 27 through the hole 28. Further, a hole 47 is formed at a position relative to the left end of the large diameter hole 26 of the main body 22.
7 is connected to a tank 43 or a pilot pump 44 via a pilot valve 48. Note 4
9 and 50 are the pump 14 and the pilot pump 4
It is a relief valve that controls the discharge pressure of 51.
A lever is used to adjust the strength of the spring 52 of the pilot valve 48. When the lever 51 is rotated clockwise, the spring 52 becomes stronger.

In the above description, the main body 22 is provided with a small diameter hole 24, a medium diameter hole 25, and a large diameter hole 26.
Instead of providing the small-diameter hole 24, the medium-diameter hole 26 may be extended so that the left end of the vacuum spool 27 contacts a snap ring (not shown) inserted into the medium-diameter hole 26.

Next, the operation of the embodiment described above will be explained. When the switching valve 42 is switched from the state shown, the oil discharged from the pilot pump 44 flows from the hole 41 to the groove 45 hole 46 hole 2.
8 and flows into the upper chamber of the cylinder 17 of the brake mechanism 16 through the hole 23, the shoe 18 receives the pressure oil and retreats to release the brake, so the output shaft 13, that is, the driven body 11 becomes rotatable. . Therefore, when the switching valve 15 is switched, the hydraulic motor 1
2 rotates to one side depending on the switching position of the switching valve 15. At this time, the differential spool 27 is pushed by the pressure oil on the front and retreats to a position where the groove 45 slightly connects to the narrow diameter part of the hole 41. At this position, the pressure reducing spool 27
The pressure oil and the decompression spring 33 are balanced and stopped. In this way, the narrow diameter portion of the hole 41 and the groove 45 constitute a second orifice.

When the lever 51 is rotated clockwise, the compressive force of the spring 52 becomes stronger, so that the lower side of the diagonal line in the pilot valve 48 moves to the left and is connected to the pilot pump 44. As a result, the oil discharged from the pilot pump 44 flows from the hole 47 to the differential piston 30.
, and the differential piston 30 moves to the right against the deflection spring 34 due to the pressure oil, so the compression force of the pressure reduction spring 33 that was pressing the pressure reduction spool 27 to the left becomes smaller. . Therefore, the pressure reducing spool 27 loses the balance between the pressure oil and the differential spring 33 and moves to the right, so that the connection between the narrow diameter portion of the hole 41 and the groove 45 is severed. As a result, the pressure oil on the left side of the vacuum spool 27 is discharged from the hole 28 and the orifice 29 to the tank 43, so the pressing force acting on the left side of the vacuum spool 27 is reduced, and the vacuum spool 27 has a groove 45 that is connected to the hole 43. Move to the left until it slightly touches the narrow diameter part of , and return to the starting position.

Thereafter, the pressure reducing spool 27 repeats the above-mentioned operation of moving to the right due to the hydraulic pressure on the left side, and the pressure reducing valve 21 performs a pressure reducing action, so that the pressure of the pressure oil against the shoe 18 of the cylinder 17 decreases, and the pressure at this time If the shoe 18 moves forward to a balanced position and the lever 51 is still rotated, it will eventually come into contact with the output shaft 18. Subsequently, when the lever 51 is further rotated, the pressing force of the spring 17 becomes greater than the force of the pressure oil of the cylinder 17, and a braking force is generated. Since the magnitude of this braking force is determined by the position of the lever 51, fine adjustment of the braking force is possible.

FIG. 2 is a diagram showing the pressure of the pressure oil acting on the left side of the pressure reducing spool 27, that is, the pressure P1 of the pressure oil in the upper chamber of the cylinder 17, and the pressure P2 of the pressure oil acting on the stepped portion of the differential piston 30. The vertical axis is the pressure and the horizontal axis is the stroke of the pressure reducing spool 27.

[Effects of the invention] As explained above, the hydraulic brake device of the invention controls the pressure reducing valve through the pilot valve which controls the pressure according to the rotational position of the lever, and the oil discharged from the pilot pump is supplied through the pressure reducing valve. Since the brake is supplied to the cylinder of the brake mechanism, the shoe provided in the cylinder is pressed by the spring, and is configured to apply braking force to the output shaft of the hydraulic motor according to the difference in the opposing hydraulic pressure. There is. As a result, the braking force is generated according to the rotational position of the lever, which has the advantage of allowing fine adjustment.

[Brief explanation of the drawing]

Fig. 1 is a mechanical diagram of an embodiment of the present invention, and Fig. 2 is a diagram showing the pressure of the pressure oil in the upper chamber of the cylinder of the brake mechanism and the pressure of the pressure oil acting on the stepped portion of the differential piston. be. 16...Brake mechanism, 22...Main body, 23,
28... Fluid discharge hole, 27... Pressure reducing spool, 29... Orifice, 30... Differential piston, 33... Pressure reducing spring, 34... Deflection spring, 48... Pilot valve.

Claims (1)

[Scope of utility model registration request] A hydraulic brake device in which the brake is released when pressure oil is supplied to the brake fluid chamber includes a main body having a fluid supply hole on one side and holes of at least two different diameters communicating with the hole. , which is slidably inserted into a medium-diameter or small-diameter hole in the same body, has an axial hole communicating with the hole on the side facing the fluid supply hole in the same body, and has an orifice on the opposite side. A vacuum spool, a differential piston that is slidably inserted across medium-large or large- and small-diameter holes in the main body and has a hole that communicates both ends; a vacuum spring that presses the vacuum spool toward the fluid supply hole of the main body; A hydraulic brake device comprising a deflection spring that presses the differential piston toward the piston, and a pilot valve that supplies control hydraulic pressure to the stepped portions of medium and large diameters, large and small diameters of the differential piston.