JPH04325802A - Controller for eddy current reduction gear - Google Patents

Abstract

PURPOSE:To improve fuel consumption rate by controlling the brake torque automatically according to the gradient of down slope, movable load, and the like thereby alleviating impact at the time of braking. CONSTITUTION:A fixed frame 9 is secured to the body side while partially projecting into a brake drum 4 coupled with a rotary shaft 1 in a wheel driving system. A large number of permanent magnets 6 are disposed peripherally with same intervals while being supported movably in the axial direction on the fixed frame 9. Each permanent magnet 6 is coupled with an actuator 10 for projecting the permanent magnet 6 into a brake drum 4 from a retracted position. Driving number of the actuator 10 is controlled by the output from an electronic controller 24 based on the difference between the torque of the rotary shaft 1 detected through a torque sensor 29 and a brake torque determined previously from the rotational speed of the brake drum 4 and the driving number of the actuator 10.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is primarily concerned with the control of eddy current reduction gears that are installed on large vehicles to assist friction brakes, and in particular, the control of eddy current reduction gears that automatically control braking torque according to driving conditions. It is related to the device.

0002

2. Description of the Related Art An eddy current type reduction gear disclosed in Japanese Patent Application No. 1-218499 has a braking drum 4 as shown in FIG.
and a magnet support ring 8. A mounting flange 2 is spline fitted to an output rotating shaft 1 protruding from an end wall of a vehicle transmission and fastened with a nut 1a. An end wall of a brake drum 3 of a parking brake and a flange portion 4a of a brake drum 4 of a speed reduction device are overlapped on the mounting flange 2 and fastened with a plurality of bolts 5 and nuts. Flange part 4a
An end edge 4c of the brake drum 4 is coupled to a large number of spokes 4b that protrude radially outward from the brake drum 4. A large number of cooling fins 7 are provided on the outer peripheral surface of the brake drum 4 at equal intervals in the circumferential direction.

A cylindrical fixed frame 9 having an inner space with a box-shaped cross section is disposed inside the brake drum 4 made of a conductor. The fixed frame 9 is fixed to the end wall of the transmission by appropriate means, and may be constructed by connecting annular end wall plates to both ends of the outer cylinder and the inner cylinder, but the fixed frame 9 shown in the figure The left half of the cylindrical frame 16 is made of a material such as iron and has a U-shaped cross section, and the cylindrical frame 15 is made of a non-magnetic material such as aluminum alloy and has an inverted L-shaped cross section. It is composed by combining. A large number of openings are provided at equal intervals in the circumferential direction in the outer cylinder of the fixed frame 9, that is, the peripheral wall of the frame 15 facing the inner peripheral surface of the brake drum 4, and the ferromagnetic plate 14 is fitted and fixed in the openings.

A plurality (preferably three) actuators 10 are supported on the fixed frame 9 at equal intervals in the circumferential direction. In the actuator 10, a rod 13 extending from a piston 12 fitted into a cylinder 11 into the inner space of the fixed frame 9 is connected to the magnet support ring 8. The magnet support ring 8 is supported by the guide wall 16a of the fixed frame 9 so as to be movable in the axial direction. A large number of permanent magnets 6 facing each ferromagnetic plate 14 are coupled to the outer peripheral surface of the magnet support ring 8 so that their polarities alternate in the circumferential direction.

During braking, when pressurized air is supplied to the left end chamber of the actuator 10, the magnet support ring 8 is pushed to the right along the guide wall 16a by the piston 12 via the rod 13, and as shown in the figure, the magnet support ring 8 is pushed to the right. 6 overlaps with the ferromagnetic plate 14. A rotating brake drum 4 is connected to a permanent magnet 6 to a ferromagnetic plate 14.
When crossing the magnetic field transmitted through the magnetic field, eddy currents flow through the brake drum 4 and the brake drum 4 is subjected to a braking torque.

[0006] In the above-mentioned eddy current type reduction gear, the actuator 10 is driven when the driver depresses the brake pedal, and is released when the driver depresses the accelerator pedal, or the brake is applied independently of the brake pedal by an operating lever on the driver's seat. and release. However, the braking torque generated by the eddy current reduction device varies depending on the number of rotations (vehicle speed) of the brake drum 4, and when the eddy current reduction device is activated at high speeds, the sudden braking action may cause shock to the vehicle body. The ride becomes uncomfortable. Also, for example, if the eddy current deceleration device is activated without pressing the brake pedal on a long downhill slope, the braking torque of the eddy current deceleration device may be too large to maintain the vehicle speed desired by the driver. Then, acceleration by operating the accelerator pedal and braking by the eddy current reduction device are repeated, resulting in poor fuel efficiency of the engine. Furthermore, repeatedly braking and releasing the eddy current reduction device using the operating lever is time-consuming and impedes safe driving.

[0007]

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to automatically control the braking torque suitable for the slope of the downhill slope, the loading weight, etc., to alleviate the shock during braking, and to reduce fuel consumption. The object of the present invention is to provide an eddy current reduction device that improves the performance.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention has a structure in which a fixed frame, a part of which protrudes into the interior of the brake drum connected to the rotating shaft of the wheel drive system, is fixed to the vehicle body. , a large number of permanent magnets arranged at equal intervals in the circumferential direction are supported movably in the axial direction on a fixed frame, and an actuator that projects the permanent magnets from a retired position into the interior of the brake drum is connected to each permanent magnet, and the actuator is connected to the actuator facing the rotating shaft. A torque sensor and a rotational speed sensor are installed at the center, and the actuator drive speed is adjusted by the output of the electronic control device based on the difference between the torque of the rotating shaft and the braking torque determined from the rotational speed of the brake drum and the actuator drive speed. It is something to do.

[0009]

[Operation] According to the present invention, the torque and rotational speed of the rotating shaft are detected by the torque sensor and the rotational speed sensor arranged opposite to the rotating shaft connecting the brake drum, and the rotational speed of the brake drum and the driving speed of the actuator are detected. From this, the braking torque of the eddy current reduction device is determined based on the characteristics of the eddy current reduction device determined experimentally in advance. An electronic control device controls the braking torque so that the braking torque becomes an appropriate value relative to the torque of the rotating shaft. Therefore, when the eddy current reduction device starts braking,
The impact acting on the vehicle body is suppressed, and during braking, the braking torque is matched to the output torque of the engine, improving fuel efficiency.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view showing the schematic structure of an eddy current reduction gear according to the present invention. The eddy current reduction gear E is arranged on the output rotating shaft 1 of the transmission 28 connected to the engine 27. A brake drum 4 is supported on the rotating shaft 1, and a fixed frame 9 is supported on the end wall of the transmission 28. The permanent magnets 6, which are arranged so that the magnetic poles facing the inner circumferential surface of the brake drum 4 are alternately different in the circumferential direction, are moved to positions where they project into the interior of the brake drum 4 along the fixed frame 9 by respective actuators 10. It differs from the conventional eddy current type speed reduction device shown in FIG. 6 in that it is driven from the inside of the brake drum 4 to the retracted position. When pressurized air from the air tank 25 is supplied to the left end chamber of the actuator 10 through the electromagnetic switching valve 26, the permanent magnet 6 is projected into the inside of the brake drum 4, and conversely, when pressurized air is supplied to the right end chamber, the permanent magnet 6 is 6 is retired from inside the brake drum 4.

As shown in FIG. 2, four sets of actuators 10 sandwiching the rotating shaft 1 are arranged on a fixed frame 9, and the permanent magnets 6 of each set are individually protruded into the inside of the brake drum 4. Adjust the braking torque of the reduction gear. For this reason, as shown in FIG. A signal is applied to the electronic control device 24, and an output signal calculated by a control program to be described later is applied to the electromagnetic switching valve 26. The torque sensor 29 detects changes in the torque of the rotating shaft 1 as changes in resistance of a resistance/strain gauge attached to the rotating shaft 1, but is not limited thereto.

The electronic control unit 24 controls the actuator 10 depending on whether or not the exhaust brake is operating during braking of the vehicle.
The braking torque Tb is controlled by adjusting the number of sets of permanent magnets 6 that drive the brake drum 4, that is, the number of permanent magnets 6 that are projected into the interior of the brake drum 4. As shown in FIG. 4, the braking torque Tb of the eddy current reduction gear
is determined from the number of permanent magnets 6 protruding into the brake drum 4 and the rotational speed of the brake drum 4 based on the characteristics determined in advance by a bench test.

Since the torque Te of the rotating shaft 1 (corresponding to the output torque of the engine 27) can be detected by the torque sensor 29, the braking torque Tb of the eddy current reduction device can be determined from the rotational speed of the rotating shaft 1 and the torque Te. Whether or not the engine is suitable for low fuel consumption operation can be determined based on the operating characteristics of the engine shown in FIG. The number of drives of the actuator 10 is adjusted depending on whether the eddy current type reduction gear is too effective or not, and the braking torque Tb of the eddy current type reduction gear is controlled to an appropriate value. As a result, an appropriate braking torque To that corresponds to the slope of the downhill slope and the loading amount of the vehicle is applied, and fuel-efficient operation of the engine is achieved.

FIG. 3 is a flowchart of a control program for performing the above-mentioned control by an electronic control unit 27 consisting of a microcomputer. This control program is repeatedly executed at predetermined time intervals. In FIG. 3, p12 to p25 represent each step of the control program. At p12, the control program is started simultaneously with the closing operation of the engine start switch 21, and p
At p13, the torque of the rotating shaft 1 is detected by the torque sensor 29, and at p14, the rotational speed of the rotating shaft 1 or the brake drum 4 is detected by the rotational speed sensor 30.

At p15, it is determined based on the signal from the exhaust brake switch 23 whether or not the exhaust brake is operating. If the exhaust brake is not working, read the ROM in p16.
From the control map A representing the relationship between the rotational speed of the brake drum 4 and the braking torque using the driving speed of the actuator 10 stored in advance as a parameter, the optimum driving speed (number of pairs) of the actuator 10 for the torque Te of the rotating shaft 1 ) is determined, the number of actuators 10 determined in p17 is driven, and the permanent magnet 6 is projected into the inside of the brake drum 4, and the process proceeds to p20.

If the exhaust brake is operating in p15, control map B showing the relationship between the number of rotations of the brake drum 4 and the braking torque when all actuators 10 are driven, which is stored in the ROM in advance, is shown in p18. From this, the braking torque Tb of the braking drum 4 is determined, all the actuators 10 are driven in p19, and it is determined in p20 whether the torque Te of the rotating shaft 1 is larger than the braking torque Tb.

If the torque Te of the rotating shaft 1 is smaller than the braking torque Tb at p20, the process returns to p13. If the torque Te of the rotating shaft 1 is larger than the braking torque Tb in p20, control is performed to express the relationship between the torque Te of the rotating shaft 1 and fuel efficiency using the rotation speed of the rotating shaft 1 stored in the RAM in p21 as a parameter. From the map C, find the ideal braking torque To of the brake drum 4 with the best fuel efficiency, and use the brake drum 4 in p22.
The ideal braking torque To is the braking torque T obtained on page 18.
In p22, it is determined whether the brake drum 4 is larger than b.
If the ideal braking torque To is larger than the braking torque Tb, the drive of some actuators 10 is canceled in p24, and the process ends in p25. If the ideal braking torque To of the brake drum 4 is smaller than the braking torque Tb at p22, p
Release the drive of all actuators 10 at step 23, and
Ends with 5.

[0018]

Effects of the Invention As described above, the present invention fixes a fixed frame, a part of which protrudes into the interior of the brake drum connected to the rotating shaft of the wheel drive system, to the vehicle body, and has a large number of permanent frames arranged at equal intervals in the circumferential direction. The magnets are supported in a fixed frame so as to be movable in the axial direction, and an actuator that projects the permanent magnets from their retired positions into the interior of the brake drum is connected to each permanent magnet, and a torque sensor and a rotational speed sensor are arranged opposite the rotating shaft. However, since the actuator drive speed is adjusted by the output of the electronic control device based on the difference between the torque of the rotating shaft and the braking torque calculated from the rotation speed of the brake drum and the drive speed of the actuator, the downhill slope , braking torque suitable for vehicle driving conditions such as loaded weight is automatically obtained, improving driving safety, reducing impact during braking, and improving fuel efficiency.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a schematic configuration of a control device for an eddy current reduction gear according to the present invention.

FIG. 2 is a front view showing the arrangement of actuators of the device.

FIG. 3 is a flowchart of a control program of the electronic control device.

FIG. 4 is a diagram showing a control map stored and set in the electronic control unit.

FIG. 5 is a diagram showing a control map stored and set in the electronic control unit. It is a flowchart of the control program of an electronic control device.

FIG. 6 is a side sectional view of a conventional eddy current speed reduction device.

[Explanation of symbols]

1: Rotating shaft 4: Braking drum 6: Permanent magnet 9
: Fixed frame 10: Actuator 23: Exhaust brake switch 24: Electronic control device 26: Electromagnetic switching valve 29: Torque sensor 30: Rotation speed sensor

Claims (1)

[Claims] Claim 1: A fixed frame that partially protrudes into the interior of a brake drum connected to a rotating shaft of a wheel drive system is fixed to the vehicle body, and a large number of permanent magnets arranged at equal intervals in the circumferential direction are moved in the axial direction on the fixed frame. an actuator is connected to each permanent magnet, and a torque sensor and a rotational speed sensor are disposed opposite the rotating shaft;
An eddy current type reduction gear that adjusts the drive speed of the actuator by the output of an electronic control device based on the difference between the torque of the rotating shaft and the braking torque determined from the rotation speed of the brake drum and the drive speed of the actuator. control device.