JP2000078831A - Eddy current decelerating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate positioning a brake drum in an axial direction by coupling an end of a spoke to a support arm via an elastic plate extended in a circumferential direction, thereby preventing looseness of a coupling part of the spoke to a brake drum. SOLUTION: A brake drum 2 having many radiating fins 2b is supported to ends of many spokes 9 extended radially at right ends from a mounting flange 10. End faces of the spokes 9 extended radially from the flange 10 are coupled to many supporting arms protruding axially from end wall faces 2c of the drum 2 via an elastic plate 27 made of a leaf spring or the like. Circumferential grooves are provided on the end faces of the spokes 9 to axially position a base end of the plate 27, coupled by a bolt 26, and the end of the plate 27 is superposed on a lower surface or inner surface of the arm and coupled with one another via radial rivets. Thus, the coupled part is not loosened by an influence of heat, but the drum can be easily positioned to the spokes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current reduction device mainly using a permanent magnet or an electromagnet for assisting a friction brake of a vehicle, and more particularly to an eddy current reduction device capable of absorbing thermal expansion of a brake drum. is there.

[0002]

2. Description of the Related Art For example, in a conventional eddy current reduction device of the type in which a magnet support cylinder is rotated forward and backward by an arrangement pitch of magnets to switch between a braking position and a non-braking position, a magnet shown in FIG. The guide cylinder 4 accommodates the support cylinders 16 and 17, and the braking drum 2 covers the outer peripheral surface of the guide cylinder 4 shown in FIG.
The guide cylinder 4 having an inner space with a rectangular cross section is made of a non-magnetic material, and a large number of ferromagnetic plates 5 are integrally connected to the outer cylinder at equal intervals in the circumferential direction. And the stationary magnet support cylinder 17 are supported. Each magnet support tube 16, 17
Are coupled to magnets 6 and 7 which are entirely opposed to ferromagnetic plate 5. The polarities of the magnets 6 and 7 facing the ferromagnetic plate 5 are alternately arranged in the circumferential direction. The guide cylinder 4 has a mounting flange 4d coupled to the left end supported by a non-rotating portion of the vehicle body.

An actuator 22a is supported on the left end of the guide cylinder 4 to rotate the movable magnet support cylinder 16 forward and backward by the pitch of the arrangement of the magnets 6. The actuator 22a has a fluid chamber defined at both ends by inserting a piston into the cylinder 23a, and an outer end of a rod connected to the piston is connected to the magnet support cylinder 16 via an arm. Actuator 22a
The fluid chambers are connected to conduits 34 and 35 for introducing pressurized air. When pressurized air is introduced from an air tank (not shown) to one of the conduits 34 and 35 through a directional switching valve, the pistons are used. A non-braking position in which the magnet support cylinder 16 is rotated forward and reverse, and the polarities of the magnets 6 and 7 facing the common ferromagnetic plate 5 are different;
The polarity of the magnets 6 and 7 switches to the same braking position. When the rotating braking drum 2 crosses the magnetic field from the magnets 6 and 7 at the braking position of the magnet support cylinder 16, a braking force based on the eddy current is generated in the braking drum 2. The eddy current is converted to heat and dissipated outside.

By the way, the braking drum of the eddy current reduction device has roughly two types of structures. One is a brake drum in which a heat absorbing portion and a supporting arm are integrally formed, and of course, a braking drum in which a heat absorbing portion and a supporting arm are integrally formed by welding is also included. The above-mentioned brake drum has an advantage that it has a simple structure and can be manufactured at low cost, but has a drawback that if the temperature of the brake drum rises during the braking operation of the eddy current reduction device, permanent deformation due to thermal expansion is likely to occur. For this reason, the braking drum having the above-mentioned structure has to limit the maximum allowable temperature.

On the other hand, in a pin-driven braking drum, the braking drum is divided into a heat absorbing portion and a supporting arm portion, and both are formed by a pin which can slide in the radial direction and a boss fitted with the pin. The combined thermal expansion of the braking drum during the braking action of the eddy current reduction device is absorbed by the pins. Since the above-mentioned brake drum can absorb thermal expansion, it is superior in operating performance at high temperatures as compared with an integral structure, but has a disadvantage that the structure is complicated and expensive.

In the eddy current reduction device disclosed in Japanese Utility Model Laid-Open No. 55778/1993, when the brake is not applied, the brake drum is positioned at the outer periphery of the spoke. Therefore, the radial positioning of the brake drum is accurate. The resonance phenomenon of the braking drum at high speed rotation can be prevented. The elastic plate (strap) serves as a means for driving the brake drum in the rotational direction by the spokes. On the other hand, during the braking operation of the eddy current reduction device, when the braking drum thermally expands, the braking drum separates from the spoke. At this time, the braking drum is positioned by the elastic plate and receives a braking torque in a direction opposite to the rotation direction. Further, the braking drum receives the reaction force of the magnet and is automatically aligned. However, in the above-described conventional eddy current reduction device, the elastic plate is fixed to the brake drum and the spokes by bolts, but the spokes are affected by heat from the brake drum.
The bolt may be loosened. Further, the axial positioning of the braking drum with respect to the spokes is unstable.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the brake drum and to provide an eddy current reduction device having a brake drum which can absorb thermal expansion and can be manufactured at low cost. Is to do.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a construction of the present invention comprises a braking drum which rotates integrally with a rotating shaft and a non-rotating portion of a vehicle which faces an inner peripheral surface of the braking drum. In the eddy current reduction device comprising magnets arranged as described above, a number of support arms protruding in the axial direction are provided at the end of the braking drum, and a part of the tip of a plurality of spokes extending radially outward from the rotation shaft. Is brought into contact with the inner peripheral surface of the braking drum, and the tip of the spoke and the support arm are connected by an elastic plate extending in the circumferential direction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in order to absorb the thermal expansion of a braking drum during braking, the tip of a spoke extending from a rotating shaft and the end of the braking drum are connected to a plurality of circumferentially extending leaf springs. They are connected by an elastic plate. At the time of braking, the elastic plate bends outward in accordance with the diameter expansion due to thermal expansion of the braking drum, and transmits the braking torque of the braking drum to the rotating shaft. At this time, the braking drum receives the magnetic reaction force and centrifugal force from many magnets, and maintains concentricity with the rotating shaft. When not braking, the braking drum contacts the spoke tips to maintain stability and facilitate assembly.

[0010]

1 is a front sectional view of an eddy current reduction device according to the present invention. The brake drum 2 having a large number of heat dissipating fins 2b has, at its right end, a large number of spokes 9 extending radially outward from a mounting flange 10 connected to, for example, an output shaft of a vehicle transmission.
Is supported by means described later. The guide cylinder 4 having an inner space 4c having a rectangular cross section is fixed to a non-rotating portion of the vehicle such that the outer cylinder 4a faces the inner peripheral surface 2a of the brake drum 2. A large number of ferromagnetic plates 5 are provided at equal intervals in the circumferential direction on the outer cylinder portion 4a of the guide cylinder 4, and bearings 19 are provided on the inner cylinder portion 4b.
, The movable magnet support tube 17 is rotatably supported, while the thin cylindrical portion 17a extending from the magnet support tube 17 supports the immovable magnet support tube 16 by a bearing 18, and the guide tube is supported by bolts (not shown). 4 is fixed to the left end wall.

The arm 2 protruding leftward from the thin cylindrical portion 17a
Actuator 22 protrudes outside through slit 13a on the left end wall of guide tube 4 and is integral with guide tube 4.
a is connected to a rod 21a projecting from a. The actuator 22a is formed by inserting a piston 24a into a cylinder 23a, and a rod 21a connected to the piston 24a protrudes from the cylinder 23a to the outside.

As shown in FIGS. 2 to 5, the present invention is applied to a tip surface 9a of a large number of spokes 9 extending radially outward from a mounting flange 10 connected to a rotating shaft, and an end wall surface 2c of a braking drum 2.
A large number of support arms 29 projecting in the axial direction are connected by an elastic plate 27 made of a leaf spring or the like. A groove 25 in the circumferential direction (the circumferential direction of the braking drum 2) is provided in the distal end surface 9 a of the spoke 9, and the base end of the elastic plate 27 is positioned in the axial direction, and is connected by a bolt 26. A part of the front end surface 9a (the left edge portion in the illustrated embodiment) is formed in a cylindrical surface so as to smoothly contact the inner peripheral surface of the brake drum 2. The distal ends of the elastic plates 27 are superimposed on the lower surface or inner surface of the support arm 29 and are connected to each other by radial rivets 28 (FIG. 5).

According to the present invention, as described above, the spoke 9 and the brake drum 2 are connected by the elastic plate 27 extending in the circumferential direction. Therefore, even if the thermal expansion of the brake drum 2 occurs, the inner peripheral surface of the brake drum 2 The braking force generated in the brake drum 2 is transmitted to the rotating shaft via the spokes 9 only by forming a gap between the end 2a and the end surface 9a of the spoke 9.

Since the base end of the elastic plate 27 is fastened to the groove 25 at the tip of the spoke 9 by the bolt 26, the brake drum 2 does not move in the axial direction with respect to the spoke 9. Also, even if the braking drum 2 thermally expands during the braking operation,
Since the brake drum 2 is supported by the elastic plate 27, the centrifugal force generated by the rotation of the brake drum 2 provides an automatic centering action, and the brake drum 2 does not become eccentric with respect to the rotation axis. Since the distal end surface 9a of the spoke 9 is engaged with the inner peripheral surface 2a of the brake drum 2, the positions of the brake drum 2 and the spoke 9 when the brake drum 2 is assembled to the spoke 9 are stable, and the assembling work is performed. Becomes easier.

In the above embodiment, an immovable magnet support tube 16 and a movable magnet support tube 17 are disposed inside the guide tube 4, and the movable magnet support tube 17 is rotated forward and reverse to disengage from the braking position. Although the case of the eddy current reduction device of the type switching to the braking position has been described, the present invention is not limited to this,
As shown in FIG. 6, one magnet support tube 17 is rotatably supported inside the guide tube 4 so as to couple the magnets 7 to the ferromagnetic plate 5 so that the polarities thereof are alternately different in the circumferential direction. By rotating the cylinder 17 forward and backward, a braking position in which each magnet 7 entirely faces each ferromagnetic plate 5 and a non-braking position in which a pair of magnets 7 having different polarities partially face the common ferromagnetic plate 5. The present invention can also be applied to an eddy current reduction device of a type that switches to a braking position (the state shown).

As shown in FIG. 7, one magnet support cylinder 17 is connected to the inside of the guide cylinder 4 so that the polarity of the magnet 7 with respect to the ferromagnetic plate 5 is two different in the circumferential direction. And the magnet support cylinder 17 is rotated forward and reverse so that the two magnets 7 facing the common ferromagnetic plate 5 have the same braking position (the state shown) and the magnet 7 facing the common ferromagnetic plate 5. The present invention is also applicable to an eddy current reduction device of a type in which the two magnets 7 are switched to a non-braking position in which the polarities of the two magnets 7 are different from each other.

As shown in FIG. 8, one magnet support cylinder 17 is connected to the inside of the guide cylinder 4 so that the polarity of the magnet 7 with respect to the ferromagnetic plate 5 is alternately different in the circumferential direction. The magnet support cylinder 17 is protruded into the brake drum 2 so that each magnet 7 is completely opposed to each ferromagnetic plate 5 in a braking position (shown in the drawing). The present invention can also be applied to an eddy current reduction device of a type in which each magnet 7 is retired and switched to a non-braking position where each magnet 7 does not face each ferromagnetic plate 5.

Further, the present invention can be applied not only to the permanent magnet type eddy current reduction device but also to a braking drum of an electromagnet type eddy current reduction device.

[0019]

As described above, the present invention comprises a braking drum which rotates integrally with a rotating shaft, and a magnet which is disposed on a non-rotating portion of the vehicle so as to face the inner peripheral surface of the braking drum. In the eddy current reduction device, a support arm protruding in an axial direction is provided at an end of the braking drum, and a part of a tip of a plurality of spokes extending radially outward from a rotation axis is brought into contact with an inner peripheral surface of the braking drum. The end of the spoke and the support arm are connected by an elastic plate extending in the circumferential direction, and the elastic plate is connected to the braking drum that generates heat by rivets. If the top end of the elastic plate is connected to the brake drum by rivets and then the base end of the elastic plate is connected to the spokes by bolts, positioning and assembly of the brake drum with respect to the spokes will not occur. Easy It made.

[Brief description of the drawings]

FIG. 1 is a left side sectional view showing an outline of an eddy current reduction device according to the present invention.

FIG. 2 is a front view showing an outline of the eddy current reduction device.

FIG. 3 is a perspective view showing a main part of the eddy current reduction device.

FIG. 4 is a left side sectional view taken along line 4A-4A in FIG. 2;

FIG. 5 is a left side sectional view taken along line 5A-5A in FIG. 2;

FIG. 6 is a side sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 7 is a front sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 8 is a left side sectional view showing another type of eddy current reduction device to which the present invention is applied.

FIG. 9 is a perspective view of a braking drum of a conventional eddy current reduction device.

FIG. 10 is a perspective view of a braking drum of a conventional eddy current reduction device.

[Explanation of symbols]

2: braking drum 2a: inner peripheral surface 2b: heat radiation fin
4: Guide tube 5: Ferromagnetic plate 6, 7: Magnet 9: Spoke 9a: Tip surface 10: Mounting flange 16, 17: Magnet support tube 22a: Actuator 25: Groove 26:
Bolt 27: Elastic plate 28: Rivet 29: Support arm

Claims (2)

[Claims] A braking drum that rotates integrally with a rotating shaft;
In an eddy current reduction device including a magnet disposed on a non-rotating portion of the vehicle so as to face an inner peripheral surface of the braking drum, a plurality of support arms protruding in an axial direction are provided at an end of the braking drum, A part of the tips of the plurality of spokes extending radially outward from the rotation shaft are brought into contact with the inner peripheral surface of the brake drum, and the tips of the spokes and the support arm are connected by an elastic plate extending in the circumferential direction. An eddy current reduction device. 2. The elastic plate according to claim 1, wherein a distal end of said elastic plate is overlapped with an inner surface of said support arm and connected by rivets, and a base end of said elastic plate is connected to a distal end surface of said spoke by bolts.
3. The eddy current reduction device according to claim 1.