JPS5943651B2 - Brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake device, and particularly to a brake device suitable as a safety brake for hoists and the like.

This type of braking device detects the falling speed of the load as centrifugal force, rotates the brake shoe using a centrifugal unit, and moves the brake shoe in the axial direction, moving the brake wheel attached to the shaft to be braked between the brake shoe and the brake disc. Recently, a brake device has been proposed that brakes the rotation of a braked shaft by clamping the shaft between the shafts.

However, in such a brake device, when the brake shoe comes into contact with the brake wheel, the friction force on the sliding surface causes the brake shoe to further rotate and press against the brake wheel, resulting in an excessive braking force and a large impact force on the braked force. This has caused damage to the product.

An object of the present invention is to provide a brake device that can prevent braking force from becoming excessive and generate appropriate braking force.

In order to achieve this object, the present invention prevents a first braking member, such as a brake shoe, from advancing beyond a predetermined position in the axial direction by a stopper, and from which point the first braking member, such as a brake wheel, Be careful not to press the second braking member (
Thus, the braking force is set to an appropriate value when the second braking member is held between the first braking member and a static 1F member such as a brake disc.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a longitudinal sectional side view of a hoist to which a brake device according to the present invention is applied.

In this figure V, 1 is a main body frame, and a driving electric motor 2 is attached to one end surface of the main body frame.

A main brake 3 is attached to the outer end surface of the driving electric motor 2, and the electric motor @2A extended toward this end surface is braked to a stop by this main brake 3 when the electric motor 2 is de-energized. There is.

On the other hand, the motor shaft 2A passes through the center of the main body frame 1 and extends outside the other end surface of the main body frame 1.

A gear case 4 is attached to the other end surface of the main body frame 1, and a reduction gear 5 housed in the gear case 4 is connected to the motor shaft 2.
The final stage gear 5A rotates the hanging load rope drum 6 within the main body frame 1 by decelerating and increasing the rotation of A.

The motor shaft 2A extends to the outer end of the gear case 4, and is braked by a safety brake 7 according to the present invention at the outer end of the gear case 4.

Fig. 2 is an enlarged detailed sectional view of the safety brake 7, Fig. 3 is a sectional view taken along line A-A in Fig. 2, Figs. 4 and 5 are front views of the centrifugal unit, and Fig. 4 is a non-operating one. The state and FIG. 5 respectively show the operating state.

A straight tooth spline 2B is formed on an extension of the motor shaft 2A, and a brake wheel 8 is attached thereto so as to be non-rotatable and movable in the axial direction with respect to the shaft.

A centrifugal frame support 9 is fixed to the end of the extension of the motor shaft 2A.
, 9B, 9C are formed at equal intervals, and the centrifugal piece 10A is placed here.
, IOB, and 10C are arranged.

Each centrifugal piece 10A to 10C is a support pin 11A. 11B, 1
1C, and is pressed against the bottoms of the notches 9A to 9C by extending the ring springs 12A and 12B to the outside of the support pins 11A to 11C on both sides of the centrifugal frame support 9.

13 is a brake case, and the gear case 1 is held by a case retainer 16 fixed to the end of the gear case 14 with a screw 15.
4 (In contrast, it is installed so that its rotational position can be adjusted.

Reference numeral 17 denotes an annular brake disc, which is supported non-rotatably and movably in the axial direction with respect to the gear case 14, and is elastically retractable by a disc spring 18.

19 is a cylindrical brake shoe with a bottom, and the cylindrical portion 19
The outer peripheral surface of A is fitted with the brake case 13 through the threaded portion 19B, so that it is supported concentrically with the motor shaft 2A.

The open end flange 19C of the brake shoe 19 extends radially outward, and the brake wheel 8 is interposed between the flange 19C and the brake disc 17.

Further, on the outer periphery of the opening end flange 19C of the brake shoe 19, an outwardly protruding protrusion 19D7) is formed.
The inner circumference Q is formed with protrusions 14A that protrude inward.When the brake shoe 19 rotates, these protrusions 19
D and 14A collide with each other to prevent the brake shoe 19 from rotating any further.

The inner peripheral surface of the cylindrical portion 19A of the brake shoe 19 is the centrifugal piece 1.
The centrifugal pieces 10A to 10C face the outer circumferential surfaces of the centrifugal pieces 10A to 10C, and when the centrifugal pieces 10A to 10C fly out due to overrotation of the motor shaft 2A in the hoist's load-unloading direction, they come into frictional contact with each other and press the brake shoe 19. They are designed to rotate in the same direction.

The characteristics of the threaded portion 19C are set so that the brake shoe 19 advances toward the brake wheel 8 due to this rotation p.

Reference numeral 20 denotes an annular rubber seal having an angular cross-section, and is attached by fitting an inward protrusion 20A at one end of its outer periphery into an annular groove 13A at the end of the brake case 13, and its inner periphery fits into the cylindrical portion of the brake shoe 19. Contact with the outer peripheral surface of 19A,
The gap between the threaded portion of the brake case 13 and the brake shoe 19 is sealed.

The inner diameter of this rubber seal 20 is the same as that of the brake shoe 19.
The inner periphery of the rubber seal 20 is expanded when it is installed, and the elastic force caused by this deformation is much smaller than the rotational force of the brake shoe 19 when the load accelerates and falls. Although it is small, it is adjusted so that it is larger than the rotational force of the brake shoe 19 due to vibration during normal operation.

In the above configuration, the hoist normally rotates the drum 6 using the drive motor 2 and the main brake 3 to hoist, lower, and stop the suspended load.

If the main brake 3 fails and loses braking force during such cargo handling work, especially during a braking stop, the suspended load will drive the hoist in the reverse direction due to its own weight and fall.

When the suspended load begins to fall in this way, the motor shaft 2A
When the rotational speed increases and reaches the planned critical rotational speed f, the centrifugal pieces 10A to 10C fly out against the ring springs 12A and 12B, as shown in FIG. It contacts the inner peripheral part of the shaped part 19A.

As a result, the brake shoe 19 is attached to the centrifugal pieces 10A to 10.
The Cic is dragged and rotated, and moves in the axial direction, that is, in the direction of the brake wheel 8, by the action of the threaded portion 19B.

When the brake shoe 19 moves and clamps the brake wheel 8 with the brake disc 17, a frictional force is generated between the clamping surfaces and the two motor shafts are braked.

At the same time, the brake shoe 19 is dragged and rotated by the frictional force between the flange 19C and the brake wheel 8. Now press 8.

Here, if the brake wheel 8 is pressed too much, the braking force becomes larger than necessary, and as mentioned above, the braked shaft 2A,
A large torsional force is generated, which may result in damage to the braked shaft 2A.

In contrast, in this embodiment, a protrusion 19D that protrudes outward is formed on the outer periphery of the flange 19C of the brake shoe 19. Since a protruding portion 14A is formed to protrude inwardly, when the brake shoe 19 rotates a predetermined amount, these inner convex portions 19D and 14A collide with each other.
The brake shoe 19 does not rotate any further.

That is, the brake shoe 19 does not move further in the axial direction and the brake wheel 8 is not pressed, so that it is possible to prevent excessive braking force from being applied to the braked shaft 2A.

Note that when the amount of wear on brake members such as the brake wheel 8 increases, even if the brake shoe 19 attempts to move in the axial direction, it is blocked by the collision between the inner ridges 19D and 14A (stopper), and the effective braking force in an emergency is reduced. Therefore, if the wear amount of the brake member exceeds the allowable value, it is necessary to replace or adjust the brake member.

However, since the emergency safety brake operates extremely less frequently than a general brake device, there is almost no need to consider replacing or adjusting such brake members.

Furthermore, after such a safety brake operation, it is necessary to manually rotate the brake shoe 19 in the opposite direction to the above-mentioned direction to move it backwards and return it to its original position. , 14A are in a colliding engagement state in the rotational direction, so there is no digging into the contact surfaces of each other, and the restoration work is facilitated.

As described above, according to the present invention, excessive braking force is prevented from being applied to the broken shaft.1. f=, the risk of damage can be prevented and safety can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional side view of a hoist to which a brake device according to the present invention is applied, FIG. 2 is a vertical cross-sectional side view of a safety brake according to an embodiment of the present invention, and FIG. A[(
FIG. 4 is a front view showing a non-operating state of the centrifugal unit portion of the safety brake shown in FIG. 2, and FIG. 5 is a front view showing the operating state of the centrifugal unit portion of the safety brake. 2A...Electric motor shaft, 8...Brake wheel, 10A-10C...Centrifugal piece, 13...
... Brake case, 14 ... Gear case, 14A ... Stopper protrusion, 17 ...
...Brake case, 19...Brake shoe, 19B...Threaded portion, 19D...Protrusion for stopper.

Claims (1)

[Scope of Claims] 1. A braked shaft, a movable member that rotates together with the braked shaft and flies out toward the outer circumference due to centrifugal force when the rotational speed reaches a predetermined rotational speed or more, and this movable member. a first braking member that engages with the movable member to rotate and move in the axial direction when the brake member protrudes in the outer circumferential direction;
a second braking member mounted so as to rotate together with the braking member and to be able to move in the axial direction;
) The braking member is pressed against the second braking member by its axial movement, and the second braking member is sandwiched between the first braking member and the stationary member, thereby controlling the braked shaft. A brake device configured to brake rotation, characterized in that a stopper is provided to stop the axial movement of the first braking member at a predetermined position, and the braking force is set to a predetermined value. 2. In claim 1, the stopper is
The first braking member is composed of a protrusion provided on the outer periphery of the case and a protrusion provided on the inner periphery of the case, and due to collision of these internal protrusions in the rotational direction, the first braking member is rotated in the axial direction. A brake device characterized by stopping movement.