JPH07329740A - Retarder for vehicle - Google Patents

Abstract

PURPOSE:To prevent the fall of brake torque by improving the cooling efficiency of a rotor at a low loss, restraining the temperature rise of the rotor. CONSTITUTION:By arranging cooling fins 21 in the state of being divided in the axial direction of a rotor 6, a cooling passage 22 extending in a rotary direction is formed on the outer periphery of the rotor 6, and cooling air 24 is run smoothly and moreover at a high speed, and at the same time the smooth inflow of the cooling air 24 is conducted by making the cooling fins 21 incline on the rotary direction rear side of the rotor 6 toward the cooling passage 22, and the improvement of the cooling efficiency of the rotor 6 at a low loss is realized, and the fall of brake torque is prevented by restraining the temperature rise of the rotor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eddy current type vehicle retarder used as an auxiliary brake for medium and large vehicles, and is intended to improve the cooling efficiency of a rotor.

[0002]

2. Description of the Related Art For medium and large vehicles such as buses and trucks,
In addition to the foot brake, an auxiliary brake is provided,
The safety of braking is improved. A retarder is known as one of the auxiliary brakes, and a typical one of the retarders is an eddy current type vehicle retarder. The eddy-current type vehicle retarder converts absorbed braking energy into heat and radiates the heat from the outer rotor. As shown in FIG. 5, the vehicle retarder 1 is connected between the propeller shafts 3 and 4 of the large vehicle 2. There is also one in which the vehicle retarder 1 is provided in the latter stage of the transmission.

A conventional vehicle retarder 1 will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view in which the conventional vehicle retarder 1 is partially cut away, and FIG. 7 is a cross-sectional view of a main part in FIG.

As shown in the figure, the propeller shaft 3
A cylindrical rotor 6 is fixed to the rotary shaft 5 connected to (4), and a housing 7 is arranged on the inner circumference of the rotor 6. The housing 7 is rotatably supported by the rotating shaft 5 via a bearing 8, and the housing 7 is in a relatively rotatable state with respect to the rotor 6. Housing 7 is mounting plate 9
It is fixed to the vehicle body of the large vehicle 2 (see FIG. 5) via the. A plurality of coils 10 are arranged on the outer peripheral surface of the housing 7 in the circumferential direction, and the coils 10 face the inner peripheral surface of the rotor 6 with a gap therebetween. That is, the rotating shaft 5 and the rotor 6 are integrally braked parts, and the housing 7 and the coil 10 are fixed parts fixed to the vehicle body. A large number of cooling fins 11 are attached to the outer circumference of the rotor 6 in the circumferential direction, and the cooling fins 11 extend parallel to the axial direction of the rotating shaft 5.

In the vehicle retarder 1 having the above structure, a magnetic flux is generated by exciting the coil 10, and an eddy current is generated inside the rotor 6 rotating integrally with the rotating shaft 5 by the magnetic flux. As a result, the rotational energy is converted into heat by the eddy current to obtain a desired braking force. At this time, since the converted heat is radiated from the rotor 6, the temperature of the rotor 6 becomes high (about 100 to 600 degrees). The rotor 6 having a high temperature is cooled by air cooling mainly by the cooling fins 11. That is, as the rotor 6 rotates, the cooling air is forced to flow into the central portion from both sides of the cooling fin 11, and the inflowing cooling air is heat-exchanged and discharged from the central portion in the radial direction.

[0006]

The above-mentioned eddy current type vehicle retarder 1 has absorbed energy (braking energy).
Is absorbed as heat, the rotor 6 generates heat to a very high temperature. The amount of heat radiation when cooling and radiating the rotor 6 determines the rated output (braking torque) of the vehicle retarder 1. As the temperature of the rotor 6 increases, the magnetic resistance of the rotor 6 increases, the amount of magnetic flux decreases, and the braking torque decreases. In the rotor 6 including the cooling fins 11 extending parallel to the axial direction of the rotary shaft 5, as shown in FIG. 8, when the braking energy is continuously absorbed as heat for about 1 minute, the absorbed torque is about half of the initial torque. Will be reduced to. Also,
Since the cooling air is forced to flow into the central portion from both sides of the cooling fin 11, the cooling air collides at the central portion, the rotational load of the rotor 6 increases, and the loss torque increases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle retarder with low loss and high cooling efficiency.

[0008]

The structure of the present invention for achieving the above object is to provide a cylindrical rotor, which rotates integrally with a rotary shaft, on the rotary shaft side, and to generate a magnetic flux inside the rotor. In a vehicle retarder in which a coil that brakes the rotation of the rotor by the generated eddy current is fixed to the vehicle body side, a large number of cooling fins divided in the axial direction of the rotor are arranged on the outer peripheral surface of the rotor, A cooling passage extending in the rotational direction is formed on the outer peripheral surface, and the cooling fins are inclined toward the cooling passage toward the rear side in the rotational direction of the rotor.

[0009]

[Operation] A magnetic flux is formed by exciting the coil,
Eddy current is generated in the rotating rotor, and the eddy current brakes the rotating shaft via the rotor. With the rotation of the rotor, cooling air flows in from the side portions of the cooling fins, and the cooling air that has flowed in merges in the cooling passage and flows to the rear side in the rotational direction at the same speed as the peripheral speed of the rotor. Since the cooling fins are inclined toward the cooling passage toward the rear side in the rotation direction of the rotor, the cooling air flows smoothly together with the cooling air flow in the cooling passage.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a vehicle retarder according to an embodiment of the present invention, which is partially cut away, and FIG.
FIG. 3 shows a plane of the rotor in a developed state.
The same members as those of the conventional vehicle retarder 1 shown in FIGS. 6 and 7 are designated by the same reference numerals, and duplicate description will be omitted.

As shown in the figure, the propeller shaft 3
A cylindrical rotor 6 is fixed to the rotary shaft 5 connected to (4), and a housing 7 rotatably supported by the rotary shaft 5 via a bearing 8 is arranged on the inner circumference of the rotor 6. . A plurality of coils 10 are provided on the outer peripheral surface of the housing 7 in the circumferential direction.
And the coil 10 faces the inner peripheral surface of the rotor 6. That is, when the coil 10 is excited, a magnetic flux is generated, and the magnetic flux generates an eddy current inside the rotor 6 that rotates together with the rotating shaft 5, and the rotational energy is converted into heat by the eddy current to obtain the desired energy. It is designed to obtain the braking force of.

On the other hand, a large number of cooling fins 21 are attached to the outer circumference of the rotor 6 in the circumferential direction, and the cooling fins 21 are divided into two in the axial direction of the rotor 6 (left and right directions in FIGS. 2 and 3). It is placed in a closed state. A cooling passage 22 extending in the rotation direction is formed on the outer peripheral surface of the rotor 6 by the cooling fins 21 in the two-divided state. The cooling fins 21 are provided so as to be inclined rearward (upward in FIG. 3) in the rotation direction of the rotor 6 toward the cooling passages 22, and the cooling fins 21 are arranged symmetrically with the cooling passages 22 interposed therebetween. .
Incidentally, as shown in FIG. 4, it is possible to dispose the cooling fins 21 with the cooling passage 22 sandwiched therebetween.

In the vehicle retarder 23 having the above structure, magnetic flux is generated by exciting the coil 10 as in the conventional case, and the magnetic flux generates an eddy current inside the rotor 6 rotating integrally with the rotating shaft 5. To do. As a result, the rotational energy is converted into heat by the eddy current to obtain a desired braking force. The converted heat is radiated from the rotor 6, so that the rotor 6 becomes hot, and the hot rotor 6 is cooled by air cooling mainly by the cooling fins 21. That is, as the rotor 6 rotates, the cooling air 24 is forced to flow from both sides of the cooling fin 21 into the central portion, and the inflowing cooling air 24 merges in the cooling passage 22 in the central portion to rotate the rotor 6 in the rotating direction. It flows to the rear side. The cooling air 24 flowing through the cooling passage 22 has an increased flow velocity at the time of merging and flows at the same speed as the peripheral speed of the rotor 6. Further, since the cooling fins 21 are inclined rearward in the rotation direction of the rotor 6 toward the cooling passage 22, combined with the flow of the cooling air 24 in the cooling passage 22, the inflow of the cooling air 24 becomes smooth. For this reason, the cooling air 24 easily flows smoothly to enhance the cooling efficiency, and the rotational load of the rotor 6 does not increase and the loss torque does not increase.

According to the vehicle retarder 23 described above, the cooling fins 21 are arranged in a state of being divided into two in the axial direction of the rotor 6 and the cooling passages 22 extending in the rotational direction are formed. It can flow at the same speed as the peripheral speed of the rotor 6. Further, since the cooling fin 21 is inclined toward the cooling passage 22 toward the rear side in the rotation direction of the rotor 6, the cooling air 24 can be smoothly introduced. Therefore, the cooling efficiency can be increased and the loss torque does not increase. Incidentally, coil 1
The arrangement of 0s, the holding structure, etc. are not limited to those in the above embodiment, and other configurations such as the use of an annular coil can be applied. Further, in the above embodiment, the tandem system in which the magnetic field generating units are arranged in parallel has been described as an example, but the present invention can be applied to a single system in which the magnetic field generating units are independently provided.

[0015]

In the vehicle retarder of the present invention, the cooling fins are arranged in a state of being divided in the axial direction of the rotor, and the cooling passage extending in the rotational direction is formed on the outer periphery of the rotor, so that the cooling air can be made smooth and smooth. Can flow at high speed. Further, since the cooling fins are inclined toward the cooling passage toward the rear side in the rotation direction of the rotor, the cooling air can be smoothly introduced. As a result, the cooling efficiency of the rotor can be improved with a low loss, the temperature rise of the rotor can be suppressed, and the reduction of the braking torque can be prevented, so that the performance can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view in which a vehicle retarder according to an embodiment of the present invention is partially cut away.

FIG. 2 is a cross-sectional view of main parts in FIG.

FIG. 3 is a plan view of the rotor in a developed state.

FIG. 4 is a developed plan view of a rotor for explaining another arrangement of cooling fins.

FIG. 5 is an explanatory view showing a mounting mode of the vehicle retarder.

FIG. 6 is a perspective view in which a conventional vehicle retarder is partially cut away.

FIG. 7 is a cross-sectional view of main parts in FIG.

FIG. 8 is a graph showing the relationship between absorption torque and rotor temperature.

[Explanation of symbols]

 5 Rotating Shaft 6 Rotor 7 Housing 21 Cooling Fin 22 Cooling Passage 23 Vehicle Retarder 24 Cooling Air

Claims (1)

[Claims] 1. A cylindrical rotor that rotates integrally with a rotating shaft is provided on the rotating shaft side, and a coil that brakes the rotation of the rotor by an eddy current generated in the rotor by a magnetic flux generated is fixed to the vehicle body side. In the retarder for a vehicle described above, a large number of cooling fins divided in the axial direction of the rotor are arranged on the outer peripheral surface of the rotor to form a cooling passage extending in the rotational direction on the outer peripheral surface of the rotor. Is inclined toward the cooling passage toward the rear side in the rotation direction of the rotor.