JP3360704B2 - Eddy current type reduction gear - Google Patents

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 speed reducer for a vehicle, and more particularly to an eddy current type speed reducer for generating a braking force when a magnet support cylinder projects into a brake drum by a fluid pressure actuator.

[0002]

2. Description of the Related Art As disclosed in Japanese Patent Application Laid-Open No. 3-86060, in a conventional eddy current type speed reducer, when a magnet support cylinder is protruded into a brake drum by an actuator, a braking torque based on the eddy current is applied to the brake drum. appear. By the way, if the pressure in the fluid pressure tank drops due to some failure during braking,
The magnet support cylinder cannot be pulled out of the brake drum by the actuator, and the brake drum is dragged, so that the vehicle cannot continue to operate smoothly thereafter.

In order to solve the above-mentioned problem, a strong return spring is conventionally mounted inside the actuator, and the pressurized fluid in the outer end chamber of the actuator is discharged to the outside. It is pulled out from the inside of the braking drum so that the braking is released. However, in the above-described current-type speed reducer, a large-sized and large-output actuator capable of pushing the magnet support cylinder into the inside of the brake drum against the force of the return spring during braking is required, and mounting on a vehicle becomes difficult.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a method for controlling the pressure of a fluid pressure tank when the pressure falls below a predetermined value.
An object of the present invention is to provide an eddy current type speed reducer in which braking is released in advance by an actuator so that smooth operation of the vehicle can be continued.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a magnet support cylinder supported on a vehicle body, a brake drum connected to a rotating shaft, and a magnet support cylinder inserted into a brake drum. In an eddy current type reduction gear having an actuator driven to a protruding braking position and a non-braking position retracted from a braking drum, and a fluid pressure tank serving as a pressure source of the actuator, the pressure of the fluid pressure tank is equal to or less than a predetermined value. Then, the actuator is driven by the output of the electronic control device based on the signal of the pressure sensor at the time of (1), and the magnet support cylinder is set to the non-braking position.

[0006]

An electromagnetic switching valve for communicating between the fluid pressure tank and the inner end chamber of the actuator during demagnetization is provided between the fluid pressure tank and the outer end chamber. Each is inserted and connected. When the pressure in the fluid pressure tank becomes equal to or less than a predetermined value during braking, the electromagnetic switching valve is switched immediately, the pressurized fluid in the fluid pressure tank is supplied to the inner end chamber of the actuator, and the magnet support cylinder is pulled out from the braking drum, The alarm is activated at the same time as braking is released.

[0007]

FIG. 1 is a schematic structural view of an eddy current type speed reducer using a permanent magnet (hereinafter simply referred to as a magnet) according to the present invention. The eddy current reduction device A includes a brake drum 15 having a cooling fin 16 connected to a number of spokes 17 projecting radially outward from a boss 18a of a rotating shaft (for example, an output shaft of a vehicle transmission) 18. ing. A large number of ferromagnetic plates 14a are connected at equal intervals in the circumferential direction to the inner end of the immobile guide cylinder 14 made of a non-magnetic material, which protrudes into the inside of the braking drum 15. On the other hand, an outer end of the guide cylinder 14 is connected to a cylinder 14b made of a magnetic material on an inner peripheral surface. A magnet 13 facing each ferromagnetic plate 14a is provided on an outer peripheral surface of a magnet support cylinder 13 made of a magnetic material.
a are coupled such that the polarities are alternately different in the circumferential direction.

The magnet support cylinder 13 includes a plurality of actuators B
As a result, it is driven to a non-braking position shown in the drawing and a braking position protruding into the braking drum 15. The actuator B has a piston 22 inserted into the cylinder 21 to define an outer end chamber 23 and an inner end chamber 24, and a rod 25 connected to the piston 22.
Are projected outside through the inner end chamber 24, and the magnet support cylinder 1
3 The air tank 12 is connected to the outer end chamber 23 of the actuator B via the electromagnetic switching valve 10 and to the inner end chamber 24 via the electromagnetic switching valve 10a. A power supply battery 8 is connected to the electromagnetic switching valves 10 and 10a and the alarm 30 via the relay switch 9.

The relay switch 9 is provided with a signal when the retarder switch 3 disposed on the steering cylinder 2 is closed, a signal from the accelerator sensor 4 when the accelerator pedal is released, and
Clutch sensor 6 when clutch pedal is released
Is closed by the output of the electronic control unit 7 based on the signal In the case of a vehicle equipped with an automatic transmission, the clutch sensor 6 need not be provided.

[0010] The present invention, when the pressure of the air tank 12 is reduced,
The output of the electronic control unit 7 based on the signal of the pressure sensor 11 when the pressure of the air tank 12 becomes equal to or less than a predetermined value, in order to avoid a state where the brake cannot be released and to allow the vehicle to continue running smoothly. To release the braking.

As shown in FIG. 2, the electromagnetic switching valve 10 releases the outer end chamber 23 to the outside at the time of demagnetization, and connects the outer end chamber 23 to the air tank 12 at the time of excitation. Conversely, the electromagnetic switching valve 10a connects the inner end chamber 24 to the air tank 12 at the time of demagnetization, and releases the inner end chamber 24 to the outside at the time of excitation.

In normal operation, when the clutch pedal is released, the retard switch 3 is closed, and when the accelerator pedal 4 is released, the release switch 9 is closed by the output of the electronic control unit 7, and the power switch 8 switches the release switch 9 from the power supply battery 8. Is supplied to each of the electromagnetic switching valves 10 and 10a and the alarm 30. The electromagnetic switching valves 10 and 10a are switched from the state shown in FIG.
Is supplied to the outer end chamber 23, and the air in the inner end chamber 24 is discharged to the outside via the electromagnetic switching valve 10a. Accordingly, the magnet support cylinder 13 is pushed into the inside of the brake drum 15 by the piston 22, and the rotating brake drum 15 is
When it crosses the magnetic field exerted on the braking drum 15 from the magnetic disk via the ferromagnetic plate 14a, it receives a braking torque based on the eddy current.

When the pressure of the air tank 12 drops below a predetermined value po during braking, the relay switch 9 is opened by the output of the electronic control unit 7 based on the signal of the pressure sensor 11, and the electromagnetic switching valves 10, 10a are turned on in FIG. It switches to the position shown in. Accordingly, the pressurized air in the air tank 12 is supplied to the inner end chamber 24 via the electromagnetic switching valve 10a, and the air in the outer end chamber 23 is discharged to the outside via the electromagnetic switching valve 10. The magnet support cylinder 13 is pulled out of the braking drum 15, and no magnetic field is applied to the braking drum 15, so that the braking is released.

FIG. 3 is a flowchart of a control program for performing the above-mentioned control by the electronic control unit 7. The control program starts at p11, and determines at p12 whether the accelerator pedal is released. If the accelerator pedal is not released, the release switch 9 is opened at p13, and p18
Proceed to.

If the accelerator pedal is released at p12, it is determined at p14 whether the clutch pedal is released. P if the clutch pedal is not released
Proceed to 13 and if the clutch pedal is released, p
At 15, it is determined whether or not the retarder switch 3 is closed. If the retarder switch 3 is not closed, the process proceeds to p13. If the retarder switch 3 is closed, it is determined at p16 whether the pressure of the air tank 12 is higher than a predetermined value po. If the pressure in the air tank 12 is lower than the predetermined value po, p13
If the pressure in the air tank 12 is higher than the predetermined value po, the relay switch 9 is closed at p17 and the process ends at p18.

In the case of an actuator using the above air pressure, an electromagnetic three-way valve is used for each electromagnetic switching valve. Although the pressure sensor may be connected to the air tank 12, if it is provided at a portion close to the actuator B, for example, at the point c in FIG. 1, the moisture in the air freezes in the pipeline between the air tank 12 and the point c. Even when the pressurized air is not sufficiently supplied to the actuator B due to, for example, the brake release operation by the electronic control unit 7 operates.

The present invention has exactly the same operation and effect even in the case of an actuator using hydraulic pressure instead of air pressure.

In the above-described embodiment, an eddy current type speed reducer of the type having a magnet support cylinder in which a large number of magnets are connected so that magnetic poles to a brake drum are alternately different in a circumferential direction has been described. It is not limited, and for example, a magnet support cylinder supported by a vehicle body, such as one using a coil-type magnet, a braking drum coupled to a rotating shaft, and a braking position where the magnet support cylinder protrudes inside the braking drum The present invention can be widely applied to an eddy current type reduction gear provided with an actuator driven to a non-braking position retreated from a braking drum and a fluid pressure tank serving as a pressure source of the actuator.

[0019]

As described above, the present invention provides a magnet support cylinder supported on the vehicle body side, a brake drum connected to a rotating shaft, a braking position where the magnet support cylinder protrudes into the brake drum, and retirement from the brake drum. In the eddy current type speed reducer provided with an actuator driven to the set non-braking position and a fluid pressure tank serving as a pressure source of the actuator, a signal of the pressure sensor when the pressure of the fluid pressure tank falls below a predetermined value is obtained. The actuator is driven by the output of the electronic control device based on the above, and the magnet support cylinder is set to the non-braking position.Therefore, there is no need to provide a strong return spring on the actuator, and braking and braking are released with a small and small output actuator. Can be used to help reduce the weight and cost of the actuator, and reduce the space required for mounting on the vehicle.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an eddy current type reduction gear according to the present invention.

FIG. 2 is a circuit diagram showing a connection of an electromagnetic switching valve in the eddy current type speed reducer.

FIG. 3 is a flowchart of a control program of the eddy current type speed reducer.

[Explanation of symbols]

B: actuator 7: electronic control unit 9: relay switch 10, 10a: electromagnetic switching valve 11: pressure sensor 12: air tank 13: magnet support cylinder 13a: magnet 1
4: Guide tube 14a: Ferromagnetic plate 15: Brake drum 1
4b: cylindrical body 23: outer end chamber

Claims (3)

(57) [Claims] 1. A magnet support cylinder supported on a vehicle body side, a brake drum connected to a rotating shaft, and a magnet support cylinder driven to a braking position protruding into the brake drum and a non-braking position retired from the brake drum. In an eddy current type speed reducer including an actuator and a fluid pressure tank which is a pressure source of the actuator, an output of an electronic control device based on a signal of a pressure sensor when the pressure of the fluid pressure tank becomes a predetermined value or less. An eddy current type speed reducer, wherein an actuator is driven to set a magnet support cylinder to a non-braking position. 2. An electromagnetic switching valve for shutting off between the fluid pressure tank and the outer end chamber of the actuator during demagnetization, and an electromagnetic switching valve for communicating with the inner end chamber when demagnetizing. The relay switch is inserted and connected to each of the energizing circuits of the electromagnetic switching valves, and the relay switch is output by the electronic control device based on the signal of the pressure sensor when the pressure of the fluid pressure tank falls below a predetermined value. The eddy current reduction device according to claim 1, which opens. 3. A signal from the pressure sensor when the pressure in the fluid pressure tank falls below a predetermined value, a signal from the accelerator sensor when the accelerator pedal is released, and a clutch when the clutch pedal is released. 3. The eddy current type speed reducer according to claim 1, wherein the relay switch is opened by an output of the electronic control device based on a signal of the sensor.