JPH0240495Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a crankshaft rotation angle detection device used to control the ignition time etc. of an internal combustion engine. This invention relates to a rotation angle detection device that obtains a predetermined electric pulse signal according to the rotation angle of a shaft (1/2 of the rotation of a crankshaft).

[Conventional technology]

When detecting the rotation angle of the rotating shaft of a power distributor using a photoelectronic pickup device, Japanese Patent Application Laid-Open No. 59632/1983 describes that a fixed slit plate for collimation is provided between the light receiving/emitting element and the rotating plate. ing.

Furthermore, the necessity of positioning this fixed slit plate and its structure were disclosed in Japanese Patent Application Laid-Open No. 56-1999, which was published after the filing of this application.
−48511, and Japanese Patent Application Laid-Open No. 48511, which was filed by the same applicant as the applicant and published after the application was filed.
It is described in Publication No. 56-83569, etc.

Below, regarding the photoelectric pick-up type rotation angle detection device described in Japanese Patent Application Laid-Open No. 56-83569,
A detailed explanation will be given based on FIGS. 1 to 9.

1 is a shaft that rotates at half the rotation speed of the engine in synchronization with the engine, 2 is a housing, and 3 is a bearing. At one end of the shaft 1 is a first collar 4.
is attached, and a pin 5 is press-fitted into the flange portion 4a of this collar 4. Pin 5 is the second collar 6
It fits into a hole 7 provided in the flange portion 6a.

A rotary plate 8 is installed between the flange parts 4a and 6a, and the second collar 6 and the first collar 4 are brought into pressure contact with the stepped part 1a of the shaft 1 with screws 9, and the rotary plate 8 is attached to both sides. It is held between the flange parts 4a and 6a.

A base 10 is made of synthetic resin and is integrally molded with a connector 11 for taking out electrical signals to the outside. The base 10 includes a printed board 12 on which an electronic circuit is formed, and a photoelectric pick-up 1.
3 is placed thereon, and this base 10 is fixed to the bottom surface of the housing 2 with screws 14.

15 is a shield plate, and side electrode 1 for high voltage power distribution
6. Provided to prevent abrasion powder from the distribution electrode 17 and center electrode 18 from adhering to the pickup 13.

FIG. 2 is a detailed view of the rotating plate 8.

Reference numeral 8a denotes a window for detecting an angle signal, and 360 windows are provided in the circumferential direction at each angle pitch of θ2 of, for example, 1°.

Reference numeral 8b indicates a reference signal detection window, and six windows are provided in the circumferential direction at every angle pitch of θ1 of, for example, 60° in a six-cylinder engine.

8c is a pin hole into which the pin 5 of FIG. 1 is inserted, and 8d is a hole into which the first collar 4 is inserted.

FIG. 3 is a diagram showing the main parts of the pickup 13, where a is a plan view, b is a sectional view taken along line bb in FIG.
c is a front view of FIG. 3a.

13a forms a first optical coupler and connects the light emitting element 1
3ea and a light receiving element 13fa. Similarly, 13b is a second optical coupler, and 13c is a third optical coupler. Second optical coupler 13b and third optical coupler 13
c is installed at an angle of θ3 with respect to the rotation center O.

Reference signal detection window 8 of rotating plate 8 in FIG.
b is detected by the first optical coupler 13a, and the angle signal detection window 8a is detected by the second optical coupler 13b and third optical coupler 13c, respectively.

13d is the mounting hole, 13g and 13h are the light emitting element 13ea (~13ec) and the light receiving element 13fa (~13
fc) is a light passage hole formed between the

FIG. 4 is an example of a circuit diagram.

Vcc is a power supply, R1 to R12 are resistors, C1, C2
is a capacitor.

13a forms a first optical coupler and connects the light emitting element 1
3ea and a light receiving element 13fa.

Similarly, 13b is a second optical coupler, which is composed of a light emitting element 13eb and a light receiving element 13fb, and a third optical coupler 13c is composed of a light emitting element 13ec and a light receiving element 13fc.

For example, the light emitting elements 13ea to 13ec include semiconductors.
It uses a light emitting diode that emits infrared rays when a forward current flows through the pn junction.

For the light receiving elements 13fa to 13fc, for example, so-called photocells are used, which generate a photovoltaic force between a p-type region and an n-type region when light is sensed.

COM1 and COM2 are comparators.

The circuit operation will be explained with reference to the time chart shown in FIG.

Each light emitting diode 13ea~13ec from power supply Vcc
A current flows through resistors R1 and R7, and the light receiving photocells 13fa to 1 facing these
In 3fc, a photovoltaic force is generated between the p-type region and the n-type region when light is sensed.

Second optical coupler 13b and third optical coupler 13c
, respective light receiving photocells 13fb and 13fc
The angle θ3 in FIG. 3 is set in relation to the angle θ2 in FIG. 2 as follows: θ3=N·θ2±θ2/2.

Therefore, as shown in FIG. 5, positive and negative alternating voltages as indicated by D are generated across the resistor R8.

To explain this in detail, first, when the light receiving photocell 13fb receives light, the resistor R8 and the comparator
At the connection point with the negative input terminal of COM2, a positive voltage is generated with the positive input terminal as a reference potential of 0, and when light is blocked, it becomes 0 and changes as shown in B.

Similarly, in the light-receiving photocell 13fc, since it is connected in antiparallel to 13fb and θ3 has the above-mentioned angular relationship, a voltage that changes negatively from the reference potential 0 as shown in C tends to occur. .

Therefore, a voltage change like the D waveform is generated across the resistor R8 by combining the voltages B and C.

Photocell 13 for light reception of first optical coupler 13a
At fa, a voltage as shown at A (FIG. 5) is generated across the resistor R2 by the light passing through the window 8b shown in FIG.

The positive input terminal of the comparator COM1 is given a voltage level obtained by dividing the power supply Vcc by resistors R3 and R4, and if an input voltage higher than this level is applied to the negative input terminal, the reference signal output terminal REF
"L" is outputted and the waveform looks like E. The resistor R5 provides hysteresis to prevent chattering in the output signal due to minute changes in the input signal.

The positive input terminal of the comparator COM2 is given a voltage level obtained by dividing the power supply Vcc by resistors R9 and R10, and if the negative input terminal changes to positive or negative based on this level, it becomes "L" like the F waveform. ，
An “H” signal is generated at the angle signal output terminal POS.
The resistor R11 is used to apply hysteresis as described above.

Therefore, by rotating the rotating plate 8, a reference signal and an angle signal are output.

Now, returning to Fig. 3, the pick-up 13 is provided with holes 13g and 13h for light to pass through. However, there are the following problems.

That is, when the light emitted from the light emitting diodes 13ea to 13ea is received by the light receiving photocells 13fa to 13fc through the window 8a of the rotary plate 8, the light passing holes 13g and 13 have an area and shape similar to that of the window 8a.
If h is not used, the p-type region of the light-receiving photocell and n
This causes disturbance in the photovoltaic force generated between the mold region and the mold region.

FIG. 6 shows the voltage waveform.

The reason for the disturbance of the voltage waveform is that the light receiving photocells 13fa to 13fc do not sense only the light exiting through one of the windows 8a of the rotary plate 8, but also sense the light leaking from the adjacent window. At the same time, the difference in light reflectance between the surfaces in the thickness direction of the rotating plate 8 and the window 8
Diffuse reflection occurs due to the difference in light reflectance of the wall surface a, resulting in the voltage waveform as described above.

To prevent this, a light emitting diode 13ea
13ec and the light receiving photocells 13fa and 13fc are provided with a plate having a slit shaped like the window 8a to provide a collimating function.

FIG. 7 shows its cross-sectional view.

A fixed slit plate 20 and a light receiving photocell 1 are installed near the light emitting surfaces of the light emitting diodes 13ea to 13ec.
Fixed slit plates 20 are provided close to the light receiving surfaces of 3fa to 13fc, respectively.

A rotary plate 8 is installed between both fixed slit plates 20, and the light emitted from the light emitting diodes 13ea to 13ec is collimated by the slits 20b and 20c and passes therethrough, and is then passed through the window 8a and the slits 20b and 20c on the light receiving side. The light is collimated and passes through the light receiving photocells 13fa to 13fc.

FIG. 8 shows a plan view of the fixed slit plate 20.

The slit 20a receives the light passing through the window 8b of the rotary plate 8, and the slits 20b and 20c receive the light passing through the window 8a.
(See Figure 2).

The opposing angle θ3 between the slits 20b and 20c is
This coincides with θ3 in FIG.

In FIG. 9, a plurality of slits 20b and 20c are provided, and the angle coincides with the angle θ2 in FIG. 2. That is, the light emitting diodes 13ea to 13ec,
If the light-receiving surface of the light-receiving photocells 13fa to 13fc is wide, for example, if it can cover three slits 20b, then the light-emitting diodes 13ea to 13ec
In addition to increasing the amount of light, the light receiving photo 13fa
It is possible to increase the amount of light received by ~13fc.

However, in the above method, the slits 20a to 20c of the fixed slit plate 20 shown in FIG.
are for the respective optical axes of the light emitting elements 13ea to 13ec and the light receiving elements 13fa to 13fc in FIG.
Must match exactly. Otherwise, the amount of light passing through the window 8a of the rotary plate 8 will vary, and the difference in peak value between the output voltages B and C of the light receiving elements shown in FIG. 5 will become large. As a result, the positive and negative duty ratios of the combined angle signal optical output signal D become unbalanced. For this reason, the variation in the duty ratio between "1" and "0" of the angle signal output F increases, and the detection accuracy deteriorates.

Therefore, in order to accurately align the slits 20a to 20c of both fixed slit plates 20, 20 with the optical axis, it is necessary to increase the accuracy of the slit plates themselves and at the same time accurately align the fixed slit plates. .

An object of the present invention is to provide a rotation angle detection device that can align two fixed slit plates with a simple operation without using a microscope or a magnifying glass.

In order to achieve this purpose, both fixed slit plates are manufactured by etching or pressing the same original plate, and each is attached to the receiving and emitting surface of the holding member so that the upper and lower surfaces of the processed surfaces face each other. However, since the fixed slit plate is symmetrical, there is a possibility that it will be assembled with the wrong side facing up.

Since the fixed slit plate has slits symmetrically, it seems that there is no effect on the detection accuracy even if the front and back sides are reversed. If the fixed slits are mounted in this manner, the machining errors of both fixed slits will be added, and the optical axis of the light passing through both fixed slits will be shifted. It was found that in this photoelectric pickup device, where an error of 1/100 millimeter affects the accuracy, such an error greatly affects the detection accuracy.

Accordingly, a further object of the present invention is to provide a rotation angle detection device that can prevent the fixed slit from being erroneously assembled from front to back.

[Means to solve the problem]

The above purpose is that the fixing slit plate has a concavo-convex portion on its outer periphery to prevent wrong assembling of the front and back sides, and is engaged with a concave-convex portion formed on each holding member to prevent wrong assembling of the front and back sides, thereby causing the fixing slit plate to This is achieved by configuring the outer peripheral shape to be symmetrical from the center position in the rotational direction.

[Effect]

According to the present invention configured in this way, since the fixed slit plate is not installed upside down, the optical axes of the light passing through both fixed slit plates can be accurately and reliably aligned, and the light receiving There is little variation in the duty ratio between "1" and "0" of the output voltage of the photocell, and a stable pulse signal can be obtained.

〔Example〕

Examples of the present invention are shown in FIGS. 10 and 11.

FIG. 10a is a plan view, FIG. 10b is a cross-sectional view, and FIG. 11 is an exploded view. Components equivalent to the conventional embodiment are designated by the same reference numerals.

The fixed slit plate 20 is glued to the holding member 30 in FIG.
The respective assembly parts to which 0 is glued are integrated together with pins 32 using screws 33.

The light emitting elements 13ea to 13ec are held by the second holding member 3.
1, the light receiving elements 13fa to 13fc are respectively inserted into the first holding member 30 and fixed by filling with adhesives 40 and 41.

The fixed slit plates 20, 20 are manufactured by etching or pressing using the same original plate, and are made so that both fixed slit plates face each other in the same projection plane (that is, the upper and lower surfaces of the processed surfaces face each other). ), the slits 20a to 20c will be accurately opposed to each other if the unevenness 20e is provided asymmetrically (with respect to the X--X line) on its outer periphery as a positioning portion for preventing wrong assembly of the front and back sides.

To give an example of each dimension from the dimensions of a general power distribution device to which this proposal is applied, the width of the slits 20b and 20c is about 0.2 mm, the hole diameter accuracy of the reference hole 20d is 0.01 mm, and the outside of the pin 32 is It is fully possible with the current manufacturing technology to manufacture a product with a diameter accuracy of 0.01 mm and a pitch accuracy of about 0.01 mm between the reference holes 20d and 20d, and even the worst manufacturing method has an error of 0.03 mm, which is about 15%. That would be enough. If further precision is required, there is an advantage that only a small amount of adjustment will be required if the present structure is temporarily assembled and then the positioning is performed using a magnifying glass or the like.

[Effect of idea]

Therefore, according to the present invention, the work of aligning the slits is extremely simple, and since there is no possibility of assembling the fixed slit with the front and back sides erroneously assembled, the slits can be aligned accurately and the rotation angle can be detected as desired. The device can be provided.

[Brief explanation of the drawing]

Figure 1 is a sectional view of an embodiment of the present invention, Figure 2 is a detailed view of the rotating plate, Figure 3 is a diagram of the main part of the pickup, and Figure 4 is a diagram of the main part of the pickup.
The figure is a rotation diagram, Figure 5 is a time chart, Figure 6 is a voltage waveform diagram, Figure 7 is a cross-sectional view of the slit plate, Figure 8 is a plan view of the slit plate, Figure 9 is a plan view of another slit plate, and Figure 9 is a plan view of another slit plate. FIG. 10 is a detailed view of the embodiment of the present invention, and FIG. 11 is an exploded explanatory view. 13e...Light emitting element, 13f...Light receiving element, 2
0... Fixed slit plate, 30... Holding member, 31
a... Guide hole, 31... Holding member, 31a... Guide hole, 32... Pin, 33... Screw.

Claims (1)

[Claims for Utility Model Registration] A power distribution shaft for an internal combustion engine that rotates in synchronization with the crankshaft; A rotating body that is attached to this shaft and rotates together with the shaft; A rotating body that is installed on one side of this rotating body and that rotates A light-emitting device comprising a light-emitting element that supplies light toward a plate, a first holding member that houses the light-emitting element, and a first fixed slit plate for collimation installed on the light-emitting surface of the first holding member. ; a light receiving element provided on the other side of the rotary plate and detecting light passing intermittently through slits bored in the rotary plate; a second holding member accommodating the light receiving element; a second fixed slit plate for collimation installed on the light receiving surface of the second holding member; a photoelectric pick-up consisting of the light emitting device and the light receiving device fixed integrally across the rotary plate; an electronic circuit for amplifying the output electrical signal of the photoelectric pickup; and the pair of fixed slit plates have the same shape, and the slits in each fixed slit plate are bored almost symmetrically, and furthermore, Both fixed slit plates are respectively fixed to the light emitting element side and the light receiving element side of both the holding parts so that the upper and lower surfaces thereof face each other during processing, and the pair of fixed slit plates In a rotation angle detection device positioned on a holding member of a photoelectric pickup, the fixed slit plate further has a concave-convex portion formed on its outer periphery to prevent wrong assembly of the front and back sides, and the fixed slit plate has a concavo-convex portion formed on the outer periphery of the plate to prevent wrong assembly of the front and back sides formed on each of the holding members. 1. A rotation angle detection device, characterized in that it is engaged with a concave and convex portion for preventing incorrect assembly, so that its outer peripheral shape is asymmetrical from the center position in the rotation direction.