JP6852843B2 - Brake device - Google Patents

Description

The present invention relates to a brake device that presses a brake pad against a brake disc to exert a braking force, and more particularly to a brake device that can suppress a decrease in the braking force even when the brake pad is worn.

Various braking devices used in general work machines such as crane hoisting devices and traversing trolleys have been proposed (see, for example, Patent Document 1). The brake device described in Patent Document 1 includes a pair of brake levers having a fixed distance between the lower ends and being configured to open and close the upper ends, and an opening and closing installed at the upper ends of the brake levers to control the opening and closing of the brake levers. It had a mechanism and brake pads installed on the brake levers, respectively.

This brake device has a configuration in which a brake disc is arranged between a pair of brake pads and the upper ends of the pair of brake levers are closed by an opening / closing mechanism to press the brake pads against the brake discs to exert braking force. Was there.

The brake device described in Patent Document 1 has a problem that the braking force is reduced as the brake pads are worn. Therefore, in order to maintain the braking force of the brake device, it is necessary to replace the brake pads frequently, and there is a problem that the cost associated with the replacement of the brake pads increases.

Japanese Patent Application Laid-Open No. 07-229527

The applicant has found that the lower side of the brake pad wears more easily than the upper side, and this wear prevents the pressing force that presses the brake pad against the brake disc from being efficiently transmitted from the brake lever. The applicant has found that the braking force of the braking device is reduced due to uneven wear of the brake pads.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a braking device capable of suppressing a decrease in braking force even when a brake pad is worn.

The brake device of the present invention for achieving the above object is a pair of brake levers arranged on both sides of the brake disc in the horizontal direction and extending in the vertical direction, and the brake. A base plate to which the lower end of the lever is connected, a support shaft for the base plate extending in the width direction extending at a right angle to the axial direction and connecting the lower end of the brake lever to the base plate, and a pair of the brake levers. The brake pad has an opening / closing mechanism for controlling the opening / closing of the upper end, a pair of brake pads arranged on both sides of the brake disc in the axial direction, and a support shaft extending in the width direction. It is provided with a connecting portion connected to the brake lever, and includes a friction material in which the brake pad contacts the brake disc and a base portion that supports the friction material and is connected to the brake lever via the connecting portion. The braking device is characterized in that the connecting portion is arranged at a position above the intermediate portion in the vertical direction of the friction material.

According to the brake device of the present invention, the stress transmitted from the brake lever is transmitted relatively large to the upper side of the brake pad on which the connecting portion is arranged. As a result, the pressing force that presses the brake pad against the brake disc becomes relatively uniform in the vertical direction of the brake pad. Since the wear of the brake pads becomes almost uniform in the vertical direction, it is advantageous to suppress a decrease in the braking force of the brake device due to the wear of the brake pads.

It is explanatory drawing which illustrates the brake device of this invention in the front view. It is explanatory drawing which illustrates the brake device of FIG. 1 by the arrow AA. It is explanatory drawing which enlarges and illustrates the periphery of the brake pad of FIG. It is explanatory drawing which illustrates the release state of the brake device of FIG. It is explanatory drawing which illustrates the tilt limiting mechanism which limits the tilt of a brake pad. It is explanatory drawing which illustrates the fixing mechanism which fixes the tilt of a brake pad.

Hereinafter, the brake device of the present invention will be described based on the embodiment shown in the figure. In the figure, the axial direction of the rotation axis of the brake disc is indicated by an arrow x, the width direction crossing the axial direction x at a right angle is indicated by an arrow y, and the vertical direction is indicated by an arrow z.

As illustrated in FIGS. 1 and 2, the brake device 1 of the present invention is used as a brake device for braking a hoisting drum of, for example, a quay crane or a gantry crane, or a brake device for braking a traversing trolley. A transmission shaft for transmitting power and a brake disc 2 fixed to the transmission shaft are arranged between the motor and the hoisting drum, and the brake device 1 is arranged in the vicinity of the brake disc 2. .. In the figure below, the brake disc 2 is shown by a alternate long and short dash line for explanation.

As illustrated in FIG. 1, the brake device 1 includes a pair of brake levers 3 arranged on both sides of the brake disc 2 in the axial direction x. The brake lever 3 extends in the vertical direction z. The lower end of the brake lever 3 is connected to the base plate 4 by the base plate support shaft 5 extending in the width direction y. The brake lever 3 is configured to be tiltable along the axial direction x about the support shaft 5 for the base plate. Further, the distance between the lower ends of the pair of brake levers 3 in the axial direction x is set smaller than the distance between the upper ends.

An opening / closing mechanism 6 for controlling the opening / closing of the upper ends of the pair of brake levers 3 is installed near the upper ends of the pair of brake levers 3. In this embodiment, the opening / closing mechanism 6 includes an actuator 7 that expands and contracts in the vertical direction z, and a link mechanism 8 that is connected between the upper end of the actuator 7 and the upper end of the brake lever 3. The link mechanism 8 has a configuration in which the upper ends of the pair of brake levers 3 are opened and closed by expanding and contracting the actuator 7.

The configuration of the opening / closing mechanism 6 is not limited to the above, and it is sufficient that the opening / closing of the upper ends of the pair of brake levers 3 can be controlled. The opening / closing mechanism 6 may be composed of, for example, a telescopic cylinder arranged between the vicinity of the upper ends of the pair of brake levers 3.

The brake device 1 includes a pair of brake pads 9 arranged on both sides of the brake disc 2 in the axial direction x. The brake pad 9 is arranged between the brake disc 2 and the brake lever 3, and is installed on the brake lever 3 via the connecting portion 10. The connecting portion 10 has a support shaft extending in the width direction y. The brake pad 9 is configured to be tiltable around a connecting portion 10 formed of a support shaft. In the figure, a part of the brake pad 9 covered with the brake lever 3 is shown by a broken line for explanation.

As illustrated in FIG. 2, the brake lever 3 is composed of a set of plate-shaped members 3a arranged side by side in the width direction y. The brake pads 9 are arranged so as to be partially sandwiched between the set of plate-shaped members 3a.

As illustrated in FIG. 3, the brake pad 9 includes a friction material 11 that comes into contact with the brake disc 2 and a base portion 12 that supports the friction material 11 and is connected to the brake lever 3 via the connecting portion 10. There is. The base portion 12 is connected to the brake lever 3 via the connecting portion 10. The connecting portion 10 is arranged at a position above the intermediate portion in the vertical direction z of the friction material 11. When the surface direction of the contact surface 11a where the friction material 11 comes into contact with the brake disc 2 is the vertical direction z, the total length of the friction material 11 in the vertical direction z is indicated by L0. Further, the length from the upper end of the friction material 11 to the center of the support shaft constituting the connecting portion 10 in the vertical direction z is indicated by L1.

The connecting portion 10 is installed at a position on the brake pad 9 where L1 is smaller than 50% of L0. The connecting portion 10 is preferably installed at a position where L1 is smaller than 30% of L0, and more preferably at a position where L1 is smaller than 25% of L0.

As illustrated in FIG. 3, when the brake device 1 is in the operating state, the opening / closing mechanism 6 moves and closes the upper ends of the pair of brake levers 3 in a direction in which they approach each other, so that the brake pads 9 are pressed against the brake disc 2. The brake disc 2 is sandwiched between the brake pads 9 on both sides in the axial direction x, and the brake device 1 exerts a braking force due to the frictional force generated between the brake disc 2 and the brake pad 9.

The contact surface 11a of the friction material 11 can be formed, for example, in a substantially rectangular shape. As illustrated in FIG. 2, the contact surface 11a formed in a substantially rectangular shape has a longitudinal direction substantially along the circumferential direction of the brake disc 2, and a lateral direction thereof generally along the radial direction of the brake disc 2. It comes into contact with the brake disc 2 in such a posture. The brake pad 9 is arranged in the brake device 1 in a posture in which the virtual surface extending along the longitudinal direction of the contact surface 11a does not overlap with the center of rotation of the brake disc 2.

The connecting portion 10 formed of a support shaft having the width direction y as an axial direction has a configuration in which the brake pad 9 is supported in a tiltable state. Therefore, when the brake pad 9 is pressed against the brake disc 2, the brake pad 9 can be tilted with the support shaft as the central axis due to the stress transmitted from the brake lever 3.

As illustrated in FIG. 4, when the brake device 1 is in the released state, the opening / closing mechanism 6 moves the upper ends of the pair of brake levers 3 in a direction in which they are separated from each other to open the brake device 1. The pair of brake levers 3 are tilted along the axial direction x, and the pair of brake pads 9 are separated from the brake disc 2. At this time, since the friction material 11 of the brake pad 9 does not come into contact with the brake disc 2, the transmission shaft to which the brake disc 2 is fixed transmits the power to the hoisting drum or the like without receiving the braking force. In the released state, the lower end of the brake pad 9 is closer to the brake disc 2 than the upper end.

Conventionally, the connecting portion 10 has been installed at a position where L1 becomes equal to 50% of L0, that is, at an intermediate portion of the brake pad 9 in the vertical direction z. When the brake device 1 is activated and the upper end of the brake lever 3 is closed, the support shaft 5 for the base plate, which is the lower end of the brake lever 3, becomes the fulcrum, and the opening / closing mechanism 6 located near the upper end of the brake lever 3 becomes the emphasis point. The brake lever 3 tilts. Therefore, the lower end of the brake pad 9 is pressed against the brake disc 2 with a larger force than the upper end. That is, when the brake device 1 is in the operating state, a larger pressing force is generated on the lower end side of the brake pad 9. The applicant has found that this is the cause of uneven wear of the brake pads 9.

In the present invention, the connecting portion 10 is arranged above the intermediate portion of the friction material 11 of the brake pad 9. Therefore, the stress transmitted from the brake lever 3 to the brake pad 9 when the brake device 1 is in the operating state tends to be concentrated at a position above the intermediate portion in the longitudinal direction of the friction material 11. The pressing force for pressing the brake pad 9 against the brake disc 2 becomes almost uniform in the vertical direction z of the friction material 11. Since it is possible to suppress the progress of wear on the lower end side as compared with the upper end side of the friction material 11, the wear of the friction material 11 proceeds relatively uniformly in the vertical direction z. Since uneven wear of the brake pad 9 can be suppressed, it is advantageous to suppress a decrease in braking force of the brake device 1 due to wear of the brake pad 9.

The closer the position of the connecting portion 10 is to the upper end of the friction material 11, the easier it is to make the pressing force when pressing the friction material 11 against the brake disc 2 uniform in the vertical direction z of the friction material 11, which is advantageous.

Since the braking force of the brake device 1 can be easily maintained, the frequency of replacement of the brake pads 9 can be reduced as compared with the conventional case. It is advantageous to suppress the cost associated with the replacement of the brake pad 9.

As illustrated in FIG. 5, a tilt limiting mechanism 13 that limits the tilt of the brake pad 9 centered on the connecting portion 10 may be installed between the brake lever 3 and the brake pad 9. The left and right sides of FIG. 5 show the released state of the brake device 1. Further, FIG. 5 illustrates a state between a set of plate-shaped members 3a constituting the brake lever 3.

In this embodiment, the tilt limiting mechanism 13 is composed of a telescopic cylinder such as a hydraulic cylinder, a pneumatic cylinder, or an electric cylinder that can be expanded and contracted in the axial direction x. This telescopic cylinder does not have to be provided with a drive source for expansion and contraction. However, the present invention does not exclude the use of a telescopic cylinder having a drive source. One end of the tilt limiting mechanism 13 is connected to the vicinity of the lower end of the brake pad 9, and the other end is connected to the brake lever 3. Both ends of the tilt limiting mechanism 13 are axially supported by a support shaft whose axial direction is the width direction y. The tilt limiting mechanism 13 is not limited to the telescopic cylinder and may be composed of a spring.

The telescopic cylinder constituting the tilt limiting mechanism 13 is preset with a maximum value and a minimum value of the total length in the axial direction thereof. That is, the telescopic cylinder is configured to be telescopic within the range set by the maximum value and the minimum value. When the brake pad 9 tilts around the connecting portion 10, if the lower end of the brake pad 9 approaches the brake disc 2, the tilt limiting mechanism 13 extends and the extension stops when the total length reaches the maximum value. To do. That is, the tilt limiting mechanism 13 restricts the lower end of the brake pad 9 from approaching the brake disc 2 more than the state shown on the left side of FIG.

When the lower end of the brake pad 9 is separated from the brake disc 2, the tilt limiting mechanism 13 contracts and the contraction stops when the total length reaches the minimum value. That is, the tilt limiting mechanism 13 restricts the upper end of the brake pad 9 from approaching the brake disc 2 more than the state shown on the right side of FIG.

The contacted surface 2a of the brake disc 2 is a surface orthogonal to the axial direction x. When the contact surface 11a of the friction material 11 is in contact with the contact surface 2a of the brake disc 2, the contact surface 11a is a surface orthogonal to the axial direction x. In a plane composed of the axial direction x and the vertical direction z, the angle θ formed when the contact surface 11a of the friction material 11 and the contact surface 2a of the brake disc 2 are separated from each other is, for example, −5 degrees to +5 degrees. Within this range, the maximum value and the minimum value of the total length of the telescopic cylinder constituting the tilt limiting mechanism 13 can be set. The tilt limiting mechanism 13 may be set within a range in which the angle θ formed is -3 degrees to +3 degrees.

Due to the installation of the tilt limiting mechanism 13, when the brake device 1 is in the released state, the vicinity of the lower end or the upper end of the brake pad 9 comes into contact with the brake disc 2, and the contacted surface 2a of the brake disc 2 is damaged or worn. It is possible to avoid the trouble of causing it. Further, it is possible to avoid a problem that the vicinity of the lower end and the vicinity of the upper end of the brake pad 9 are worn. It is advantageous to avoid a problem that the braking force of the braking device 1 decreases with use.

If the range of possible angles of the formed angle θ is set too large, for example, ± 10 degrees, the brake pad 9 may tilt and come into contact with the brake disc 2. If the range of possible angles of the formed angle θ is set too small, for example, ± 0.5 degrees, the followability of the brake disc 2 to the contact surface 2a decreases when the brake pad 9 is pressed against the brake disc 2. As a result, there is a problem that the braking force is reduced.

It is advantageous to prevent the brake pad 9 from coming into contact with the brake disc 2 when the brake device 1 is in the released state and affecting the rotation of the brake disc 2. It is advantageous to avoid malfunction of the operation of the general work machine in which the brake device 1 is installed.

The installation position of the tilt limiting mechanism 13 is not limited to the above. One end may be connected to the vicinity of the upper end of the brake pad 9 and the other end may be connected to the brake lever 3. However, when the brake pad 9 is installed near the lower end, the distance from the connecting portion 10 which is the center of the tilt of the brake pad 9 becomes larger, so that the force generated in the tilt limiting mechanism 13 due to the tilt of the brake pad 9 is smaller. Become. The tilt limiting mechanism 13 is advantageous for limiting the tilt of the brake pads 9 with a smaller force.

The configuration of the tilt limiting mechanism 13 is not limited to the above. The structure is not limited to the telescopic cylinder as long as the tilt of the brake pad 9 about the connecting portion 10 can be restricted. For example, the tilt limiting mechanism 13 may be configured by a resistance member arranged between the support shaft constituting the connecting portion 10 and the through hole of the base portion 12 penetrating the support shaft to increase the frictional resistance. The resistance member may be composed of a spring having one end of the spring fixed to the support shaft and the other end fixed to the brake pad 9. This spring is wound around the outer peripheral surface of the support shaft in a state where the support shaft and the central shaft are aligned with each other.

For example, the tilt limiting mechanism 13 may be configured by a plate-shaped member installed on the brake lever 3 and arranged at a predetermined interval from the brake pad 9. This plate-shaped member has a structure that limits the tilt of the brake pad 9 by colliding the tilted brake pad 9.

As illustrated in FIG. 6, a fixing mechanism 14 for fixing or releasing the tilt of the brake pad 9 may be installed between the brake lever 3 and the brake pad 9. The left side of FIG. 6 shows the operating state of the brake device 1, and the right side of FIG. 6 shows the released state of the brake device 1. Further, FIG. 6 illustrates a state between a set of plate-shaped members 3a constituting the brake lever 3.

In this embodiment, the fixing mechanism 14 is a telescopic cylinder 14a such as a hydraulic cylinder, an air cylinder, or an electric cylinder that can be expanded and contracted in the axial direction x, and one end of the telescopic cylinder 14a and a side close to the brake pad 9. It is provided with a locking piece 14b installed on the side. The other end of the telescopic cylinder 14a is connected to the brake lever 3. The expansion / contraction cylinder 14a includes a drive source for expansion / contraction.

The locking piece 14b is configured to be in contact with the base portion 12 of the brake pad 9 at at least two locations, an upper side and a lower side of the connecting portion 10.

As illustrated on the left side of FIG. 6, when the brake device 1 is in the operating state, the telescopic cylinder 14a contracts so that the locking piece 14b is separated from the brake pad 9. Therefore, the brake pad 9 can be tilted around the connecting portion 10. The state of the fixing mechanism 14 at this time is hereinafter referred to as a fixing release state.

As the upper end of the brake lever 3 closes, the brake pad 9 is pressed against the brake disc 2. The brake pad 9 tilts to an angle at which most of the contact surface 11a of the friction material 11 comes into contact with the contact surface 2a of the brake disc 2.

Since the fixing mechanism 14 is in the unlocked state when the brake device 1 is in the operating state, the brake pad 9 is automatically tilted at an angle at which the pressing force is more evenly transmitted from the brake pad 9 to the brake disc 2. It is advantageous for suppressing a decrease in the braking force of the brake device 1 due to wear of the brake pad 9.

As illustrated on the right side of FIG. 6, when the brake device 1 is in the released state, the telescopic cylinder 14a extends and the locking piece 14b comes into contact with the base 12 of the brake pad 9. Since the locking piece 14b comes into contact with the brake pad 9 on both the upper side and the lower side of the connecting portion 10, the brake pad 9 cannot be tilted about the connecting portion 10. The state of the fixing mechanism 14 at this time is hereinafter referred to as a fixed state.

Since the fixing mechanism 14 is in the fixed state when the brake device 1 is in the released state, it is possible to prevent the brake pad 9 from tilting and coming into contact with the brake disc 2.

The configuration of the fixing mechanism 14 is not limited to the above. If the structure is such that the brake pad 9 can be tilted when the brake device 1 is in the operating state and the brake pad 9 can be prevented from tilting when the brake device 1 is in the released state, the fixing mechanism 14 is a telescopic cylinder. The configuration is not limited to the combination of the 14a and the locking piece 14b.

For example, the tilt limiting mechanism 13 composed of the telescopic cylinder illustrated in FIG. 5 may be used as the fixing mechanism 14. In this case, the telescopic cylinder cannot be expanded or contracted when the brake device 1 is in the released state, and the telescopic cylinder can be expanded or contracted when the brake device 1 is in the operating state.

Depending on the type of general work machine, the axial direction x of the brake disc 2 may be another direction such as a vertical direction instead of the horizontal direction. When the axial direction x of the brake disc 2 is in the vertical direction, the brake device 1 is installed in the general work machine in a posture in which the pair of brake pads 9 sandwich the brake disc 2 from the vertical direction. Even in such a case, if the brake device 1 is provided with the tilt limiting mechanism 13 or the fixing mechanism 14, the brake pad 9 tilts due to its own weight and comes into contact with the brake disc 2 when the brake device 1 is in the released state. It is possible to avoid the trouble that occurs.

1 Brake device 2 Brake disc 2a Contacted surface 3 Brake lever 3a Plate-shaped member 4 Base plate 5 Support shaft for base plate 6 Opening and closing mechanism 7 Actuator 8 Link mechanism 9 Brake pad 10 Connecting part 11 Friction material 11a Contact surface 12 Base 13 Tilt limiting mechanism 14 Fixing mechanism 14a Telescopic cylinder 14b Locking piece x Axial direction y Width direction z Vertical direction L0 (longitudinal direction of friction material) Total length L1 (from the upper end of the friction material to the connecting part) Length θ (friction material and brake disc) ) Friction

Claims (4)

A pair of brake levers arranged on both sides of the brake disc with the horizontal direction as the axial direction and extending in the vertical direction, a base plate to which the lower end of the brake lever is connected, and the axial direction at right angles to each other. A support shaft for a base plate extending in the width direction extending across the brake lever to connect the lower end of the brake lever and the base plate, an opening / closing mechanism for controlling the opening / closing of the upper ends of the pair of brake levers, and the brake disc. The brake includes a pair of brake pads arranged on both sides in the axial direction, and a connecting portion having a support shaft extending in the width direction and connecting the brake pad to the brake lever. In a brake device including a friction material in which a pad contacts the brake disc and a base portion that supports the friction material and is connected to the brake lever via the connection portion.
A braking device characterized in that the connecting portion is arranged at a position above the intermediate portion in the vertical direction of the friction material. The brake device according to claim 1, wherein the connecting portion is arranged at a position of 25% or less from the upper end with respect to the total length which is the length from the upper end to the lower end of the friction material. Tilt of the brake pad so that the angle formed by the contact surface of the brake pad orthogonal to the axial direction of the brake disc is in the range of −5 degrees to +5 degrees with respect to the contact surface orthogonal to the axial direction of the brake disc. The brake device according to claim 1 or 2, further comprising a tilt limiting mechanism for limiting. When the brake pad is separated from the brake disc, the brake pad is fixed so as not to tilt about the support shaft of the connecting portion, and when the brake pad is in contact with the brake disc, the brake The brake device according to any one of claims 1 to 3, further comprising a fixing mechanism for putting the pad in a fixed release state capable of tilting around the support shaft of the connecting portion.

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