JP2772845B2 - Engine speed control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine speed control device for a construction machine or the like, which controls the engine speed by a step motor.

[Conventional technology]

FIG. 4 shows an example of an engine speed control device used in a power shovel.
A governor 4 and a step motor 6 are provided. The step motor 6 and the control lever of the governor 4 are connected by a link rod 8. Step motor 6
Is driven by the step motor control device 1.
The step motor control device 1 includes a rotation speed setting device 10 for setting the rotation speed of the engine 2, an engine rotation sensor 12, a controller 14 for comparing and processing signals from the rotation speed setting device 10 and the engine rotation sensor 12, A driver 16 receives a step motor drive signal from the controller 14 and drives the step motor 6 to rotate forward and reverse.

The operator operates the rotation speed setting device 10 provided on the operation panel or the like to set the rotation speed of the engine 2 arbitrarily. The controller 14 compares and processes the signal from the engine rotation sensor 12 with the set rotation speed, and sends a step motor drive signal to the driver 16. The driver 16 drives the stepping motor forward and reverse according to the signal, operates the control lever of the governor 4 to adjust the fuel injection amount, and controls the rotation speed of the engine 2.

[Problems to be solved by the invention]

In the above-described conventional engine speed control device,
In order to use the step motor 6, the step motor control device 1 is required. The step motor control device 1 includes a rotation speed setting device 10, an engine rotation sensor 12, and a controller 14.
And electric components other than the step motor 6 such as the driver 16. If these components fail, the engine speed cannot be set or maintained.

Therefore, if work with a power shovel is performed in a river, on a muddy ground or in a dangerous place, etc., even if the above-mentioned breakdown is found, not only can you escape from it but also move to a place where you can get service. It is extremely difficult. This is dangerous for the operator, and the repair operation itself cannot be performed smoothly and safely.

Until the trouble is resolved, the operation must be stopped, and the efficiency is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved engine which can easily and reliably set the engine speed even if a step motor control device fails, and which can be easily put into practical use with a relatively simple configuration. It is to provide a rotation speed control device.

[Means for solving the problem]

According to the present invention, there is provided an engine speed control device including a step motor control device for controlling a rotation speed of an engine by driving a step motor in accordance with a command from a controller, wherein the step motor is controlled independently of the step motor control device. Is provided, the backup device includes a pulse generator for transmitting a pulse to the step motor and a device for driving the pulse generator, and the pulse generator corresponds to a pulse pattern. An engine speed control device is provided, comprising: a pattern generating gear having a projection formed on an outer peripheral surface; and a brush arranged to contact the projection.

〔Example〕

Hereinafter, an engine speed control device improved according to the present invention will be described in detail based on embodiments with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an engine speed control device improved in accordance with the present invention. The difference from the conventional example of FIG. And that the backup device 3 capable of driving the step motor 6 independently is provided. Therefore, the same parts as those in FIG. 4 are denoted by the same reference numerals.

The backup device 3 includes a changeover switch 18, a pulse generator 20 that sends a pulse to the step motor 6, a changeover switch 22, and a battery 24. The changeover switch 18
Normally, the switching position is such that the step motor control device 1 is turned on, but when an electrical trouble occurs in the device 1, the backup device 3 is switched to be turned on. In this example, the changeover switches 18 and 22 are linked, and are turned ON and OFF at the same time. Both switches 18 and 22 are ON
The backup device 3 and the step motor 6
Are connected. In this example, the stepping motor 6 is a two-phase excitation type of a two-phase stepping motor in which A-phase, B-phase, and phase windings are formed on the stator side.

FIG. 2 schematically shows the pulse generator 20, in which both ends of a shaft 30 are rotatably supported by bearings 26 and 28.
On the shaft 30, a small gear 32 and a pattern generating gear 34 are fixed. A large gear 36 is meshed with the small gear 32. A shaft 38 of the large gear 36 is rotatably supported on another bearing 40, and an end of the shaft 38 is fixed to a handle 42 as a driving device. The pattern generating gear 34 is made of a conductive member in a disk shape, and has an A-phase and a B-phase on its outer peripheral surface along the circumferential direction.
Protrusions (teeth) that form a phase, a phase, and a phase pulse pattern are provided (hatched portions in the figure). The projections of each phase are formed with a phase shift of 90 degrees, and the phase relationship between the phases is such that the projections are shifted by half in the order of A phase, B phase, phase and phase along the circumferential direction ( (Overlapping in the circumferential direction).

On the other hand, on the radial outer side of the pattern generating gear 34, there are four types of brushes that contact the projections of each phase, that is, A-phase brushes 44, B
A companion brush 46, a companion brush 48, and a companion brush 50 are arranged. The brushes 44 to 50 are insulated by insulating materials 52, 54 and 56, respectively, so that the phases do not interfere. Each of the brushes 44 to 50 is connected to a corresponding phase winding of the stepping motor 6.

The shaft 30 of the pattern generating gear 34 is connected to the battery 24 via a contact 58.

Next, the operation of the embodiment of the present invention configured as described above will be described with reference to FIGS.

In FIG. 1, the operation of controlling the stepping motor 6 by the stepping motor control device 1 and adjusting the rotation speed of the engine 2 is as described in FIG.

When an electrical trouble occurs in the step motor control device 1, as shown in FIG. 1, the changeover switch 18 is switched to turn off the circuit connecting the step motor control device 1 and the step motor 6, and the backup device The circuit connecting the motor 3 and the step motor 6 is turned on. Selector switch 22
Also turns on at the same time.

When the handle 42 of the pulse generator 20 is turned, the gear 36
The pattern generating gear 34 rotates according to the speed increase ratio between. The protrusions, which are pulse patterns formed on the pattern generating gear 34, sequentially contact the brushes 44 to 50 of each phase. The voltage of the battery 24 is sent to the corresponding phase windings of the step motor 6 via the phase brushes 44-50. The pulse pattern is
This is a repetitive pattern of ON and OFF, and is continuously generated by operating the handle 42. The waveform of the voltage sent from the pulse generator 20 to the step motor 6 is shown in FIG. The phases are shifted by 90 degrees from each other, and the patterns are shifted by half each other because of the two-phase excitation method. Depending on the rotation direction of the handle 42 and thus the pattern generating gear 34, the pulse generation rotates forward and reverse, and accordingly, the rotation direction of the step motor 6 also rotates forward and reverse. The engine speed increases with forward rotation in the rotation direction, and decreases with reverse rotation.

Since the rotation direction and the rotation angle of the step motor 6 can be arbitrarily controlled by the above operation of the steering wheel, the fuel injection amount can be appropriately increased / decreased via the governor 4 and the engine speed can be arbitrarily set.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) Since a backup device capable of driving the step motor independently of the step motor control device is provided, a failure of an electric component or other electric trouble occurs in the step motor control device other than the engine governor or the step motor. However, by operating the backup device, the engine speed can be arbitrarily set and maintained. Therefore, if work by construction equipment is performed in rivers, muddy grounds, or dangerous places, etc., even if the above troubles occur, it is possible to easily escape and receive services. Can be moved up. Thereby, the safety of the operator is reliably ensured, and the repair work can be performed smoothly and safely. In addition, until a service person comes,
Since the work can be performed using the backup device, it is extremely useful in terms of efficiency.

(2) The backup device includes a pulse generator that sends a pulse to the step motor, and a device that drives the pulse generator, wherein the pulse generator has a pattern in which protrusions corresponding to the pulse pattern are formed on the outer peripheral surface. Since it is configured to include a generating gear and a brush arranged to be in contact with the projection, when the above trouble occurs, the engine speed can be arbitrarily set easily and reliably, and relatively It can be easily put into practical use with a simple configuration.

As mentioned above, although this invention was demonstrated in detail based on the Example, this invention is not limited to the said Example,
Various changes or modifications can be made within the scope of the present invention.

For example, as a step motor, a two-phase step motor
The present invention has been described by taking the two-phase excitation method as an example.
Even in a step motor in which various coil phases such as two-phase and four-phase and other excitation methods are combined, only the number of brushes and the pattern of the pattern generating gear are different, and it goes without saying that the present invention is applied. Absent. Further, the present invention can be realized by using a motor as a driving means of the pulse generator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an engine speed control device showing one embodiment of the present invention. FIG. 2 is a schematic sectional view showing one embodiment of the pulse generator used in FIG. FIG. 3 is a diagram showing a pulse pattern generated by the pulse generator of FIG. 2; FIG. 4 is a schematic diagram showing an example of a conventional engine speed control device. 1 Step motor control device 2 Engine 3 Backup device 4 Governor 6 Step motor 10 Rotation speed setting device 12 Engine rotation sensor 14 Controller 16 Driver 18 Switch 20 ... Pulse generator 22 ... Changeover switch 24 ... Battery 34 ... Pattern generating gear 42 ... Handle 44 ... A phase brush 46 ... B phase brush 48 ... Phase brush 50 ... Phase brush 52 to 56 ……Insulating material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-20951 (JP, A) JP-A-60-212655 (JP, A) JP-A-61-23203 (JP, A) JP-A-63-63 246449 (JP, A) Japanese Utility Model Showa 57-204439 (JP, U) Japanese Utility Model Showa 61-86549 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 41/22

Claims (1)

(57) [Claims] An engine speed control device comprising a step motor control device for controlling a rotation speed of an engine by driving a step motor in accordance with a command from a controller, wherein the step motor is controlled independently of the step motor control device. A backup device that can be driven is provided, the backup device includes a pulse generator that sends a pulse to the step motor, and a device that drives the pulse generator;
The engine generator according to claim 1, wherein the pulse generator includes a pattern generating gear having a protrusion corresponding to a pulse pattern formed on an outer peripheral surface, and a brush arranged to contact the protrusion.