JPH0746065Y2 - Eddy current retarder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an eddy current type retarder for decelerating and braking a vehicle, and in particular, an eddy current for protecting a permanent magnet that causes an eddy current in a rotor from moisture and dust. Regarding the expression retarder.

[Prior Art] Generally, a deceleration braking device that gives stable and continuous deceleration braking to a vehicle in order to prevent acceleration that occurs in the vehicle at the time of downhill on a long slope and prevents burnout of a foot brake that is a main brake. An eddy current retarder is known as a (retarder). As such an eddy current type retarder, the "reduction device" disclosed in JP-A-50-61574 is known.

By the way, in order to reduce the size and weight of the eddy current retarder, it is a good idea to employ a compact permanent magnet having a strong magnetic force as a magnetic force source for generating an eddy current in the rotor.

FIG. 7 shows an eddy current type speed reducer a which the applicant of the present invention previously developed uses a permanent magnet as a magnetic force source.

As shown in the figure, a drum-shaped rotor b is coaxially attached to an output shaft a of a transmission of an automobile, and a stator c is positioned inside the drum-shaped rotor b, and a stator c is attached to a transmission case d via a support metal fitting e. It is supported. The rotor b is a conductor and magnetic material, for example,
It is molded from Fe material.

On the other hand, the stator c has an annular support ring f arranged concentrically with the output shaft a, and an S pole and an N pole on the support ring f at predetermined intervals along the circumferential direction. It is composed of permanent magnets g which are circumferentially arranged alternately.

A stator c including the permanent magnet g and the support ring f
Is sealed by a casing h as shown in FIG. 8 which allows the stator c to reciprocate in the drum-shaped rotor b.

As shown in FIG. 7, the casing h is provided on the inner peripheral side of the drum-shaped rotor b with a predetermined distance from the rotor b, and is located between the stator c and the rotor b. There is a braking zone i that magnetically connects the permanent magnet g of the stator c and the rotor b to brake the rotor b, and a release zone j that magnetically shields the permanent magnet g of the stator c to release the braking. is doing.

As shown in FIG. 8, the braking zone i is formed of a pole piece portion k made of a ferromagnetic material shown by diagonal lines and a portion other than the pole piece portion k made of a weak or non-magnetic material shown by dots. There is. As shown in FIG. 8, the pole piece portion k is intermittently connected in the circumferential direction according to the distance between the permanent magnets g so as not to be paired with the permanent magnets g provided around the support ring f at a predetermined distance. Is provided for the purpose.

Therefore, as shown by the solid line in FIG. 7, this braking zone i
In addition, when the stator c is moved by the actuator l, a magnetic circuit that connects the S pole and the N pole is formed between the adjacent permanent magnet g having a different polarity of the stator c on the fixed side and the rotor b on the rotating side. As a result, an eddy current that gives deceleration braking to the rotation of the rotor b flows on the inner peripheral surface of the rotor b facing the braking zone i, a braking force is applied to the output shaft 1 fastened to the rotor b, and deceleration braking of the vehicle is performed. To be achieved.

On the other hand, the release zone j is formed of a ferromagnetic material over the entire circumference in the circumferential direction as shown in FIG.

Therefore, as shown by the broken line in FIG. 7, this release zone j
When the stator c is moved by the actuator 1, a magnetic circuit connecting the S pole and the N pole is formed between the permanent magnet g of the stator c on the fixed side and the release zone j on the fixed side. , The stator c is in a magnetic shield state. Therefore, the rotor c, which is the rotating side, is connected to the stator c.
Does not leak, no eddy current is generated in the rotor b, and the deceleration braking of the vehicle is released.

As described above, the casing h performs ON / OFF of the braking force, and the ferromagnetic material portion and the weak or non-magnetic material portion that configure the casing h are fitted and fitted to each other by a screw or the like. Water and dust outside the casing h are prevented from entering the inside of the casing h, and deterioration and demagnetization of the permanent magnet g inside the casing h due to these moisture and dust are prevented.

[Problems to be Solved by the Invention] In the eddy current type retarder shown in FIG.
During the deceleration braking, an eddy current as energy loss is generated on the inner peripheral surface of the rotor b facing the stator c, so that the rotor b generates heat. The heat generated by the rotor b is transmitted to the casing h that surrounds and seals the stator c, and the temperature inside the casing h may rise up to about 100 ° C. at the maximum. As a result, the air inside the casing h, which is closed by the casing h, thermally expands, the internal pressure of the casing h increases, and the casing h is tightly coupled to form the casing h. Part of the air in the casing h is discharged from a slight gap such as a fitting portion between a ferromagnetic material portion indicated by diagonal lines in FIG. 8 and a weak or non-magnetic material portion indicated by dots.

After that, when the stator c is moved to the position shown by the broken line in FIG. 7 and the braking force is turned off, the stator c enters the magnetic shield state and no eddy current is generated in the rotor b, and the temperature of the rotor b decreases. Then, the temperature inside the casing h also returns to the original room temperature.

At this time, since a part of the air inside the casing h is discharged to the outside of the casing h and the volume of the air is reduced from the original state, if the air is cooled to the original room temperature as it is, the inside of the casing h becomes a negative pressure state. Become.

Therefore, the casing h having a negative pressure inside is
Moisture and dust outside the casing h will be sucked into the casing h through a small gap such as a fitting portion between the ferromagnetic portion and the weak or non-magnetic portion.

As described above, the moisture and dust sucked into the casing h deteriorates and demagnetizes the permanent magnet g of the stator c inside the casing h. In particular, when the permanent magnet g is formed of a neodymium-iron-based material so as to exert a strong magnetic force, it is significantly deteriorated due to the characteristics of the material, which is a serious problem.

The purpose of the present invention devised to solve the above problems is:
The present invention provides an eddy current retarder that protects a permanent magnet that causes an eddy current in a rotor from moisture and dust.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a rotor provided on a rotary shaft, and braking the rotary shaft by bringing the rotor close to the rotor and separating the rotor from the rotor. A permanent magnet for releasing the braking, a case for allowing the permanent magnet to move closer to and away from the case and sealing the case, and a breather means provided in the case for sucking and discharging the inside and outside air of the case. There is.

[Operation] According to the above configuration, the permanent magnet is allowed to move from a position close to the rotor that applies braking to the rotating shaft to a position separated from the rotor that releases the braking, and is sealed by the case. Therefore, moisture and dust outside the case do not enter the inside of the case.

Therefore, the deterioration and demagnetization of the permanent magnet due to these moisture and dust are prevented in advance.

In addition, the eddy current generated in the rotor during deceleration braking of the rotating shaft causes the rotor to generate heat, and the heat generated in the rotor causes the temperature in the case to rise. Is sucked and discharged, the case internal pressure does not increase due to the increase of the case internal temperature.

That is, the case is not damaged due to the increase in the case internal pressure.

In addition, when the breather is released from the braking state of the rotating shaft, the breather means returns the room temperature that has risen to room temperature, and the inside of the case becomes negative pressure. Prevent the phenomenon of suction into the case.

[Embodiment] An embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, a flange portion 2 is formed on an output shaft 1 of a transmission of an automobile so as to extend outward in the radial direction of the shaft 1. The flange portion 2 is provided with a brake drum 3 for a parking brake. Eddy current retarder rotor 4
And are fastened together by mounting bolts 5.

The rotor 4 is formed of a conductor and a magnetic material, for example, an Fe material, into a cylindrical shape with a bottom, that is, in a so-called drum shape.
The stator 6 positioned inside the drum-shaped rotor 4 and supported by a transmission case (not shown) is slidable in the axial direction of the drum, in other words, the rotor 4
It is provided so that it can move closer to and away from it.

The stator 6 is composed of an annular support ring 7 arranged concentrically with the output shaft 1 and a permanent magnet 8 attached on the support ring 7. Supported by. The permanent magnet 8 constituting the stator 6 is made of a rare earth element such as neodymium to be lightweight and compact in order to exert a strong magnetic force, and faces the inner peripheral surface of the drum-shaped rotor 4 in the circumferential direction thereof. , N poles are arranged on the support ring 7 in an even number (8 to 12) at predetermined intervals so as to alternate.

As shown in FIG. 1, the stator 6 including the permanent magnets 8 and the support ring 7 is sealed by a hollow cylindrical case 9 that allows the stator 6 to reciprocate in the drum-shaped rotor 4. There is. That is, the stator 6 in the case 9 is movable toward and away from the rotor 4.

The case 9 is located on the inner peripheral surface of the drum-shaped rotor 4 and is provided with a predetermined gap from the rotor 4, and the magnetic permeability portion 10 of the stator 6 and the stator 6 are provided.
And a magnetic shield portion 11 for magnetically shielding the magnetism.

When the stator 12 in the case 9 is moved to the magnetic permeability portion 10 as shown by the solid line in FIG. 1 by using the actuator 12 attached to the case 9, the permanent magnet 8 of the stator 6 on the fixed side is moved. A magnetic circuit that connects the S pole and the N pole is formed between the rotor 4 that is the rotating side, and an eddy current that gives deceleration braking to the rotation of the rotor 4 flows on the inner peripheral surface of the rotor 4, and an output that is the rotating shaft. Deceleration braking of shaft 1 is achieved.

On the other hand, when the stator 6 in the case 9 is moved to the magnetic shield portion 11 by the actuator 12 as shown by the broken line in FIG. 1, the stator 6 is in the magnetic shield state and the deceleration braking of the output shaft 1 is released. Will be done.

As shown in FIGS. 1 and 8, the magnetically permeable portion 10 and the magnetic shield portion 11 forming the case 9 are composed of a ferromagnetic material portion indicated by diagonal lines and a weak or non-magnetic material portion indicated by dots. It is formed by closely fitting and screwing each other.

As shown in FIG. 1, a feature of the present invention is that, as shown in FIG. 1, a breather hole 13 for communicating the inside and outside of the case 9 is provided as a breather means for sucking and discharging the inside and outside air of the case 9.
That is the point.

As shown in FIG. 1, the breather hole 13 is provided at the end of the inner peripheral portion of the hollow cylindrical case 9 defined by the brake drum 3 for the parking brake and the edge 14 of the case 9. ing. That is, this breather hole 13 is
Is provided in a place where moisture and dust outside the case 9 do not easily enter the case 9.

The operation of this embodiment having the above configuration will be described.

As shown in FIG. 1, the permanent magnet 8 of the stator 6 that applies decelerating braking to the output shaft 1 by generating an eddy current in the rotor 4 is located near the rotor 4 that applies braking to the output shaft 1. Allowing movement from the rotor 4 for releasing the braking to a position away from the rotor 4, that is, the magnetic permeability portion 10 of the case 9.
Since it is sealed by the case 9 while allowing the movement from the position facing to the position facing the magnetic shield part 11 of the case 9, moisture and dust outside the case 9 cannot enter the inside of the case 9. Absent.

Therefore, the deterioration and demagnetization of the permanent magnet 8 in the case 9 due to these moisture and dust are prevented in advance.

Further, during deceleration braking of the output shaft 1 in which the stator 6 is opposed to the magnetically permeable portion 10, eddy current generated in the rotor 4 causes the rotor 4 to generate heat, and the heat generated in the rotor 4 causes the temperature in the case 9 to rise. However, since the inside and outside air of the case 9 is sucked and discharged by the breather hole 13 provided in the case 9, the rise in the case 9 internal pressure due to the rise in the case 9 internal temperature does not occur, and the temperature increase is suppressed to some extent. It

That is, in the breather hole 13, the air inside the case 9 leaks from the fitting portion between the ferromagnetic material portion and the weak or non-magnetic material portion forming the case 9 due to the rise of the internal pressure of the case 9.
It is possible to prevent backlash from occurring in the fitting portion.

Further, when the eddy current type retarder is brought into a brake release state in which the rotor 4 returns to room temperature from the brake state in which the rotor 4 generates heat,
The temperature inside the case 9 that had risen returns to room temperature, and the inside of the case 9 becomes negative pressure. At this time, the breather hole 13 is provided in the case 9
External moisture / dust will be sucked into the case through the fitting part between the ferromagnetic part and the weak or non-magnetic part.
Prevents the phenomenon of dust suction.

Therefore, the permanent magnet 8 in the case 9 is completely shielded from moisture and dust outside the case 9, and deterioration and demagnetization of the permanent magnet 8 due to the moisture and dust are prevented in advance. At the same time, deterioration and demagnetization of the permanent magnet due to an excessive temperature rise are prevented.

If a waterproof / dustproof filter for filtering moisture / dust is provided at the opening of the breather hole 13 shown in FIG. 1, the effect of shielding the permanent magnet 8 against moisture / dust is further improved.

A modified embodiment of the present invention is shown in FIG.

As shown in the drawing, in this modified embodiment, a ball valve type check valve 15 is used for the breather means shown as the breather hole 13 in FIG. This check valve 15
When the internal pressure of the case 9 inside the case 9 becomes negative, the ball valve 18 urged by the spring 17 opens and the case 9
The outside air on the outside 19 flows into the case 9.

The check valve 15 as the breather means is installed at the first place.
The location is not limited to the one shown in the figure, and it may be anywhere as long as moisture or dust outside the case 9 does not easily enter the case 9 through the check valve 15. For example, as shown in FIG. It may be installed in.

Another modified embodiment is shown in FIG.

As shown in the figure, in this modified embodiment, in addition to the check valve 15 for inflowing the outside air into the inside 16 of the case 9 as shown in FIG. 9 is provided with a check valve 21 for flowing out to the outside 19.

Therefore, when the internal pressure of the case 9 inside the case 9 rises, the inside air of the case flows out of the case 9 through the outflow check valve 21, and when the internal pressure of the case 9 becomes a negative pressure, the inflow check valve 15
And then flows into the case 9.

Yet another modified embodiment is shown in FIG.

As shown in the drawing, in this modified embodiment, the inflow check valve 15 and the outflow check valve 21 shown in FIG. 4 are made of rubber lead instead of the ball valve type check valves 15 and 21. The valve type check valves 22 and 23 are used. With this configuration, the ball valve type check valves 15 and 2 shown in FIG.
Cheaper than 1.

Yet another modified embodiment is shown in FIGS. 6 (a) and 6 (b).
Shown in. As shown, in this modified embodiment, a slitted grommet 24 is used for the breather means.

That is, the breather means is constructed by fitting the slitted grommet 24 shown in FIG. 6 (b) into the breather hole 13 shown in FIG. Grommet with this slit
24 is a rubber grommet that closes the breather hole 13 and has a slit 25 serving as a breather passage through which the inside and outside air of the case 9 breathes through the slit 25 according to the pressure change between the inside 9 of the case 9 and the outside 19 of the case 9. It is provided.

By configuring the breather means in this way, since the slitted grommet 24 also serves as intake and exhaust air, it is less expensive than the reed valve type check valves 22 and 23 shown in FIG.

The other configurations of the modified embodiment shown in FIGS. 2 to 6 are the same as those of the embodiment shown in FIG.
Needless to say, the effect is basically the same.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects can be exhibited.

(1) The permanent magnet that causes an eddy current in the rotor can be completely protected from moisture and dust, and deterioration and demagnetization of the permanent magnet due to the moisture and dust can be prevented.

(2) Deterioration and demagnetization of the permanent magnet due to excessive temperature rise can be prevented.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of an eddy current type retarder showing an embodiment of the present invention, FIG. 2 is a side sectional view of a breather means showing an essential part of a modified embodiment of the present invention, and FIG. 3 is the above breather. Partial side sectional view of an eddy current retarder showing the installation location of the means, 4th
FIG. 5 and FIG. 5 are side sectional views of a breather means showing a main part of still another modified embodiment, and FIG. 6 (a) is a side sectional view of a breather means showing a main part of yet another modified embodiment. FIG. 6 (b) is a front view of FIG. 6 (a), FIG. 7 is a side sectional view of an eddy current retarder previously developed by the applicant, and FIG.
It is a partial perspective view which shows the casing of a figure. In the figure, 1 is an output shaft which is a rotary shaft, 8 is a permanent magnet, 9 is a case, 13 is a breather hole as a breather means, 15, 21, 22
Reference numerals 23 and 23 are check valves as a breather means.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A rotor provided on a rotating shaft, a permanent magnet for braking the rotating shaft by bringing the rotor closer to the rotor, and releasing the braking by separating the rotor and the permanent magnet. An eddy current retarder comprising a case that allows movement and is hermetically sealed, and a breather means that is provided in the case to suck and exhaust air inside and outside the case.