JPH0329751Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle speed device for a vehicle equipped with a two-speed reduction type differential capable of providing two types of reduction ratios.

[Conventional technology]

In large vehicles, in order to always be able to use near the maximum output of the engine through normal gear shifting operations in response to large changes in running load, the final reduction mechanism for this vehicle is equipped with two rows behind the general final reduction gear. A two-speed reduction type differential is known, which is configured by adding a pair of gears to provide two types of reduction ratios.

Conventionally, the vehicle speed device of a vehicle equipped with this two-speed reduction type differential is equipped with a speedometer that detects and displays the vehicle speed from the rotation of a flexible cable installed on the output shaft of the vehicle's transmission. By dividing the speedometer and installing a reduction gear, and switching this gear at the same time when switching the differential reduction ratio to either the high speed side or the low speed side, a single speedometer can be used to control two types of speed reduction gears depending on the differential reduction ratio. Displays vehicle speed.

[Problem that the invention attempts to solve]

However, in conventional vehicle speed systems, when the reduction ratio of the differential becomes finer, the structure of the reduction gear becomes complicated, which raises the cost.

An object of the present invention is to provide a vehicle speed device for a vehicle with a two-speed reduction type differential that can display vehicle speeds according to the reduction ratio of the two-speed reduction type differential with a simple configuration without using a reduction gear.

[Means for solving problems]

The configuration of the present invention for achieving the above object will be explained based on the drawings of the embodiments.

The vehicle speed device of this invention for a vehicle with a two-speed reduction type differential is:
A magnetic speedometer 20, a two-speed reduction type differential 10 that can take two types of reduction ratios, a shift unit 11 that switches the reduction ratio of this differential 10 to either a high speed side or a low speed side, and this shift unit 11. A control switch 15 is provided to operate the control switch 15. The magnetic speedometer 20 includes a flexible cable 21 that rotates in accordance with the rotation of the output shaft 19 of the transmission 18, a drive shaft 22 connected to the cable 21 and having a permanent magnet 23 attached to its tip, and the permanent magnet 23. The guide metal plate 24 is arranged at intervals on the outer periphery of the pointer 26 and rotates together with the pointer 26 by the rotational torque of a magnet, and the hairspring 27 adjusts the rotational torque of the guide metal plate 24.

This magnetic speedometer 20 uses a magnetic field control plate 3 between a permanent magnet 23 and an induction metal plate 24 to control the lines of magnetic force of the magnet 23, instead of correcting the rotational speed of a flexible cable using a conventional reduction gear.
0 is provided, and this magnetic field control plate 30 is moved in and out between the permanent magnet 23 and the induction metal plate 24 by an actuator 31 operated by switching the control switch 15.

[Effect]

When the control switch 15 switches the shift unit 11 to the low speed side, the actuator 31 moves the magnetic field control plate 30 of the magnetic speedometer 20 to the permanent magnet 23.
and the induction metal plate 24. As a result, the lines of magnetic force coming out of the magnet are weakened by the magnetic field control plate 30 and act on the induction metal plate 24. Therefore, the eddy current generated in the induction metal plate is reduced, and the force acting between this current and the lines of magnetic force is reduced. Therefore, the rotational force is reduced.

Next, when the control switch 15 switches the shift unit 11 to the high speed side, the actuator 31
The magnetic field control plate 30 is connected to the permanent magnet 23 and the induction metal plate 2.
Pull it out from between 4. This causes the induction metal plate 24 to rotate without reducing the force acting between the magnetic lines of force from the magnet and the eddy current.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

As shown in the figure, 10 is a two-speed reduction type differential. A shift unit 11 is installed on the side of this differential 10.
is installed. One end of an air line 12 is connected to the shift unit 11, and the other end of the air line 12 is connected to an air tank 13. Further, a normally closed solenoid valve 14 is interposed in the middle of the air pipe line 12.
When the solenoid valve 14 is closed, the shift unit 11 does not operate, the rear axle 17 is engaged with the low speed gear, and the solenoid valve 14 is closed.
In the open state, the shift unit 11 is operated to bring the rear axle 17 into mesh with the high speed gear. A battery 16 is connected to a control input of the solenoid valve 14 via a control switch 15 . The control switch 15 is attached to a change lever (not shown) of the transmission 18.

20 is a magnetic speedometer. Worm gear 21a provided at one end of the flexible cable 21
meshes with the output shaft 19 of the transmission 18. A drive shaft 22 is connected to the other end of the cable 21 . A permanent magnet 23 is attached to the tip of this drive shaft 22.
Inductive metal plates 24 are arranged on the outer periphery of the magnet 23 at intervals. A shaft 25 is erected on this metal plate 24, and a pointer 26 is fixed thereto. One end of the hairspring 27 is wound around the shaft 25, and the other end is fixed to the frame 28.

The characteristic feature of this embodiment is that a magnetic field control plate 30 is provided between the permanent magnet 23 and the induction metal plate 24 to control the lines of magnetic force of the magnet 23, and this magnetic field control plate 30 is operated by switching the control switch 15. The point is that the actuator 31 moves the permanent magnet 23 into and out between the permanent magnet 23 and the induction metal plate 24. The magnetic field control plate 30 has a cylindrical shape and is provided so as not to interfere with the rotations of the permanent magnet 23 and the induction metal plate 24. The magnetic field control amount of the magnetic field control plate 30 is determined according to the ratio of the rotational speed when the rear axle 17 is engaged with a low-speed gear to the rotational speed when the rear axle 17 is engaged with a low-speed gear. In this example, the magnetic field control plate 30 is made of a ferrite metal plate,
Actuator 31 consists of a solenoid. 32
is a scale plate.

In the vehicle speed device having such a configuration, when the control switch 15 is in the OFF state, the solenoid valve 14 is closed and the actuator 31 is inactive, as shown by the solid line in the figure. When the solenoid valve 14 closes, the shift unit 11 does not operate, the rear axle 17 of the differential 10 is engaged with the low speed gear, and the vehicle travels at the vehicle speed V. Further, when the actuator 31 is in an inoperative state, the magnetic field control plate 30 is inserted between the permanent magnet 23 and the induction metal plate 24. As a result, lines of magnetic force acting on the induction metal plate from the magnet are reduced, and eddy currents generated in the induction metal plate are reduced. Therefore, the force that acts between the eddy current and the magnetic lines of force and rotates the induction metal plate is reduced. When the rotational torque of the induction metal plate 24 and the repulsive force of the hair spring 27 are balanced, the pointer 26 comes to rest.
The speed of the scale plate 32 is displayed.

Next, while the vehicle is traveling at the same speed V, when the control switch 15 is switched from the off state to the on state as shown by the broken line in the figure, the solenoid valve 14 opens and the actuator 31 is activated. When the solenoid valve 14 opens,
Shift unit 11 has been activated, and until now differential 10 has been activated.
The rear axle 17, which had been meshing with the low speed gear, now meshes with the high speed gear, and the vehicle speed becomes V×α. Further, when the actuator 31 is activated, the magnetic field control plate 30 comes out from between the permanent magnet 23 and the induction metal plate 24. As a result, cable 2
The force between the magnetic lines of force coming out of the magnet 23 and the eddy current caused by the rotation of the induction metal plate 2 does not decrease.
4 and rotates it.

As a result, the rotational torque of the induction metal plate 24 changes in accordance with the amount of change in rotation of the rear axle 17 due to switching of the shift unit 11.
displays the vehicle speed of V×α.

[Effect of idea]

As described above, according to the present invention, the rotational torque of the induction metal plate is changed in accordance with the amount of change in rotation of the rear axle with a simple configuration of only the movement of the magnetic field control plate in and out. The vehicle speed of a vehicle equipped with a two-speed reduction type differential can be displayed according to the reduction ratio of the differential by eliminating the need for a reduction gear, which is a complex mechanism.

[Brief explanation of the drawing]

The figure is a configuration diagram of a vehicle speed device according to an embodiment of the present invention. 10... Two-speed reduction type differential, 11... Shift unit, 15... Control switch, 18... Transmission,
20... Magnetic speedometer, 21... Flexible cable, 22... Drive shaft, 23... Permanent magnet, 2
4... Induction metal plate, 26... Pointer, 27... Hair spring, 30... Magnetic field control plate, 31... Actuator.

Claims (1)

[Claim for Utility Model Registration] A flexible cable that rotates in accordance with the rotation of the output shaft of a transmission, a drive shaft that is connected to this cable and has a permanent magnet attached to its tip, and a space provided around the outer circumference of this permanent magnet. A magnetic speedometer that includes an induction metal plate that is arranged in a direction and rotates together with the pointer by the rotational torque of a magnet, and a hairspring that adjusts the rotational torque of the induction metal plate; In a vehicle speed system for a vehicle equipped with a two-speed reduction type differential, the vehicle is equipped with a reduction type differential; a shift unit that switches the reduction ratio of this differential to either a high speed side or a low speed side; and a control switch that operates this shift unit. A magnetic field control plate is provided between the permanent magnet and the induction metal plate to control the magnetic lines of force of the magnet, and the magnetic field control plate is moved in and out between the permanent magnet and the induction metal plate by a switching signal from the control switch. A vehicle speed device for a vehicle with a two-speed reduction type differential, characterized by comprising an actuator.