JP3372429B2 - Apparatus for detecting ignition timing in internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a device for detecting whether ignition timing is appropriate for movement of a piston in an internal combustion engine. 2. Description of the Related Art In general, in an internal combustion engine, a flywheel on a crankshaft is provided with an ignition timing mark indicating a phase of an ignition timing in a specific cylinder, and an index piece is provided on a non-rotating side such as a cylinder block. And irradiating them with a timing light that flashes when the ignition plug in the specific cylinder is energized, and whether or not the ignition timing mark that appears stationary by the irradiation of the timing light matches the index in the index piece. Thus, the appropriateness of the ignition timing is detected. [0003] In this case, in the conventional apparatus, the index piece is connected to a cylinder block of an internal combustion engine and a transmission case connected to an output side thereof, as described in, for example, Japanese Utility Model Publication No. 59-33906. The indicator piece is cut and raised integrally so as to protrude into the transmission case, or the indicator piece is made of a metal plate, and the rear end plate is inserted between the rear end plate. The index piece is fixed to the inner surface of the transmission case by welding so as to protrude from both surfaces of the plate. [0004] However, in each of these conventional arts, a rear end plate is provided so that an index piece projects from the rear end plate. The indicator piece protrudes from the surface of the rear end plate during handling such as assembling and transporting the rear end plate when the transmission case is combined with the transmission case. However, there is a problem in that there is a great possibility that the detection of the ignition timing will be distorted due to bending deformation. [0005] In particular, when the index piece is cut and raised on the rear end plate as in the former case, the index piece can be provided at a position of a correct phase with relatively high accuracy. Since a hole for cutting and raising the index piece is formed, the airtightness in the transmission case is reduced due to the hole, and as in the latter case, a metal plate is formed. Although fixing the indicator piece made of steel to the rear end plate by welding does not cause a decrease in the airtightness in the transmission case, it causes a displacement during welding, so the indicator piece must be positioned at the correct phase. However, there is a problem in that the accuracy of the detection of the ignition timing is low. An object of the present invention is to provide an ignition timing detection apparatus which solves these problems at once. SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention provides a transmission case for covering a flywheel on a crankshaft on an output side surface of a cylinder block, with a rear end plate interposed therebetween. In the internal combustion engine, a through hole is formed in the rear end plate on the outer periphery of the flywheel, and an indicator for an ignition timing mark provided on the flywheel is provided in the through hole. The index piece is detachably inserted so as to protrude into the transmission case from the outer surface of the rear end plate opposite to the inside of the transmission case, and the base end of the index piece is attached to the outer surface of the rear end plate or It is detachably fixed to the cylinder block. " [0008] The operation and effect of the present invention, by such a configuration,
After the transmission case is connected to the cylinder block with the rear end plate interposed therebetween, the indicator piece can be attached to the rear end plate such that the indicator piece projects into the transmission case. In other words, the rear end plate can be transported or mounted between the cylinder block and the transmission case in a state where the index piece is not attached to the rear end plate. It is possible to avoid bending and deformation of the index piece during handling as in the related art. In addition to this,
Since the index piece is removably inserted into the through hole formed in the rear end plate, the through hole can be closed with the index piece, and the index piece can be provided at a position of a correct phase. is there. Therefore, according to the present invention, the ignition timing can be detected with high accuracy without lowering the hermeticity in the transmission case, and the detection can be reliably prevented from being out of order. Have. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes a cylinder head 3 on an upper surface of a cylinder block 2.
Shows a multi-cylinder internal combustion engine in which an oil pan 4 is fastened to the lower surface of a cylinder block 2. An output shaft end 5 a of a crankshaft 5 protrudes from an output side surface 2 a of the cylinder block 2, At the end 5a,
The flywheel 6 is fixed, and an ignition timing mark 6 a indicating the phase of the ignition timing in a specific cylinder of the internal combustion engine 1 is engraved on the outer peripheral surface of the flywheel 6. Reference numeral 7 denotes a transmission case. The transmission case 7 is fastened to the output side surface 2a of the cylinder block 2 by a plurality of bolts 8 so as to cover the flywheel 6. A rear end plate 9 made of a metal plate is sandwiched between the case 7 and the output side surface 2a of the cylinder block 2. Reference numeral 10 denotes an index piece formed by bending a metal plate into an L-shape.
Is provided with an index 10a '. A through hole 11 is formed in the outer peripheral portion of the flywheel 6 in the rear end plate 7, and the tip 10 a of the indicator piece 10 is inserted into the through hole 11. The rear end plate 9 is removably inserted so as to protrude into the transmission case 7 from the outer surface of the rear end plate 9 opposite to the inside of the transmission case 7, and the base end 10 b of the indicator 10 is attached to the outer surface of the rear end plate 9. On the other hand, a bolt 12 and a nut 13 screwed to the bolt 12 are detachably fixed. A bolt 1 for fixing the body portion 10b of the indicator piece 10 to the outer surface of the rear end plate 9
2 is fixed to the rear end plate 9 by welding or the like so as to project from the inner surface to the outer surface. In this case, the base end portion 10a of the indicator piece 10 is detachably fixed to the outer surface of the rear end plate 9 instead of the cylinder block 2.
May be configured so as to be detachably fixed to the outer surface of. With this configuration, after the transmission case 7 is coupled to the cylinder block 2 with the rear end plate 9 interposed therebetween, the index piece 10 is moved to the rear end plate 9 with respect to the index piece. 10 can be mounted such that the tip 10 a of the projection 10 protrudes into the transmission case 7. That is, the rear end plate 9 can be transported without the indicator piece 10 attached thereto, or can be handled so as to be assembled between the cylinder block 2 and the transmission case 7. While the rear end plate 9 is being handled, it is possible to reliably prevent the indicator piece from being bent and deformed as in the related art. The tip 10a of the indicator piece 10 is
By being detachably inserted into the through hole 11 formed in the rear end plate 9, the through hole 11 is
, And the index piece 10 can be provided at the position of the correct phase. Furthermore, the base end 10b of the indicator piece 10 is connected to the rear end plate 9
On the other hand, the nut 1 screwed into the bolt 12 fixed thereto
3. The index piece 10
If the bolts 12 and nuts 13 used for the fixing are dropped, they will not fall into the transmission case 7. When the indicator piece 10 is attached to the outer surface of the rear end plate 9 with bolts 12 and nuts 13, the base end 10b of the indicator piece 10 and the outer surface of the rear end plate 9 4, the washer 14 may be interposed as shown by a two-dot chain line in FIG.

[Brief description of the drawings] FIG. 1 is a vertical sectional front view showing a main part of an internal combustion engine. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 is an enlarged sectional view taken along line III-III of FIG. 2; FIG. 4 is an exploded view of FIG. FIG. 5 is an exploded perspective view. [Explanation of symbols] 1 Internal combustion engine 2 Cylinder block 2a Output side of cylinder block 5 Crankshaft 6 flywheel 6a Ignition timing mark 7 Transmission case 9 Rear end plate 10 Indicator pieces 10a 'indicator 11 Through hole 12 volts 13 nuts

Claims (1)

(1) An internal combustion engine comprising a transmission case, which covers a flywheel on a crankshaft, connected to an output side surface of a cylinder block with a rear end plate interposed therebetween. A through-hole is formed in a portion of the plate on the outer periphery of the flywheel, and an index piece provided with an index for an ignition timing mark provided on the flywheel is provided in the through-hole. It is inserted so as to protrude into the transmission case from the outer surface opposite to the inside, and the base end of the indicator piece is detachably fixed to the outer surface of the rear end plate or the cylinder block. For detecting ignition timing in an internal combustion engine.