Title of Invention

"GROMMET HOLDING STRUCTURE ON AN ENGINE"

Abstract A grommet holding structure on an engine having a crankcase, a covering member, a flywheel magneto consisting of a stator and a rotor and disposed in a space defined by the crankcase and the covering member, a pulse signal sensor disposed in the space to monitor a detecting member attached to the outer circumference of the rotor, a harness including wires connected to the pulse signal sensor and the stator, and a grommet attached to the crankcase; wherein the grommet holding structure holds the grommet so that the harness is extended therethrough in a direction parallel to a crankshaft.
Full Text [Technical Field of the Invention]
The present invention relates to improvements in a
grommet holding structure on an engine and a structure of an engine.
[Description of the Related Art]
A pulse signal sensor combined with an engine measures the rotating speed of a crankshaft to control ignition timing and a self-starting motor. A holding structure for holding such a pulse signal sensor is disclosed in Utility Model Publication No. 2510184 on ."Pulse signal sensor Holding
Structure for Force-Air-Cooled Engine
In Fig. 2 of the cited reference, there are shown a
pulse signal sensor 24, a lead wire 16, a rotor 15b, and a
detecting member 25. The frequency of passage of the detecting member 25 attached to the rotor 15b rotating together
i,^
with a crankshaft 6a is counted by the pulse signal sensor 24.

As shown in Fig. 1 of the cited reference, the pulse signal sensor 24 and the lead wire 16 are disposed on a line
passing the crankshaft 6a Therefore, the pulse signal sensor 2.4 and the lead wire 16 project radially outward.
[Problem to be Solved by the Invention] As shown in Fig. 3 of the cited reference in a cross-sectional view, an exhaust gas produced in a cylinder 1 is guided by an exhaust system, not shown, from the cylinder 1 via a space under (or above) a crankcase 2 to a space beside a rear wheel 5.
Generally, the exhaust system, not shown, is extended near the pulse signal sensor 24 and the lead wire, 16.
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When the exhaust system is extended near the pulse signal sensor 24 and the lead wire 16, the exhaust system must greatly be deflected from a straight line, and there are many restrictions in the arrangement of the pulse signal sensor 24, the lead wire 16 and the exhaust system.
Accordingly, it is an object of the present invention
to provide techniques capable of enhancing freedom in arranging lead wires (harness) and an exhaust system.
[Means for Solving the Problem]
According to claim 1, in a grommet holding structure
on an engine having a crankcase, a covering member, a
flywheel magneto consisting of a stator and a rotor and disposed in a space defined by the crankcase and the covering member, a pulse signal sensor disposed in the space to monitor a detecting member attached to the outer circumference of the rotor, a harness including wires connected to the pulse signal sensor and the stator, and a grommet attached to the crankcase to extend the harness therethrough outside the crankcase, the grommet holding structure holds the grommet so that the harness is extended therethrough in a direction substantially parallel to a crankshaft.
Since the harness is extended substantially in parallel to the crankshaft, the interference of the harness with devices arranged around the engine can easily be avoided as compared with a state in which the harness is extended radially outward. The radially outward projection of the harness is equivalent to increase in the size of the engine which makes the arrangement of the devices around the engine and the extension of the harness difficult. The technique stated in claim 1 solves such a problem, enables forming the engine in a compact construction and facilitates the ar-
rangement of the devices around the engine and the extension of the harness.
According to claim 2, in the grommet holding structure on an engine, the crankcase is provided with an opening extending substantially in parallel to the crankshaft, a grommet receiving recess is formed from one end of the opening toward the crankshaft, the grommet is inserted in the grommet receiving recess from outside, a grommet holding tongue is extended from the covering member so that the grommet holding tongue is inserted in the opening and holds the grommet to restrain the grommet from radially outward movement.
The grommet is held in place with the grommet holding tongue extending from the covering member. Bolts or screws for fastening the grommet are unnecessary and hence the number of parts can be reduced.
According to claim 3 , in a structure of an engine having a crankcase, a covering member, a flywheel magneto consisting of a stator and a rotor and disposed in a space defined by the crankcase and the covering member, a pulse signal sensor disposed in the space to monitor a detecting member attached to the outer circumference of the rotor, a harness including wires connected to the pulse signal sensor and the stator, and a grommet attached to the crankcase to extend the harness therethrough outside the crankcase, a
grommet holding structure holds the grommet so that the harness is extended therethrough in a direction substantially parallel to a crankshaft, and an exhaust system is disposed so as to surround a hollow defined by the crankcase .
In addition to the effect of claim 1, the exhaust system can be extended without being interfered with by the harness. Therefore, the exhaust system can be extended near the crankcase and the covering member, and the engine including the exhaust system can be formed in a compact construction.
The present invention relates to a grommet holding structure on an engine having a crankcase, a covering member, a flywheel magneto consisting of a stator and a rotor and disposed in a space defined by the crankcase and the covering member, a pulse signal sensor disposed in the space to monitor a detecting member attached to the outer circumference of the rotor, a harness including wires connected to the pulse signal sensor and the stator, and a grommet attached to the crankcase;
wherein the grommet holding structure holds the grommet so that the harness is extended therethrough in a direction parallel to a crankshaft.
[BRIEF DESCRIPTION OF THE/DRAWINGS]
[Fig. 1]
Fig. 1 is a side view of a motor scooter relating to the present invention.
[Fig. 2]
Fig. 2 is a sectional view of a power unit relating to the present invention.
[Fig. 3]
Fig. 3 is a side view of an engine relating to the present invention.
[Fig. 4]
Fig. 4 is a side view of a cylinder head relating to the present invention.
[Fig. 5]
Fig. 5 is a plan view of the cylinder head relating to the present invention.
[Fig. 6]
Fig. 6 is an exploded perspective view of a engine relating to the present invention.
[Fig. 7]
Fig. 7 is a perspective view of assistance in explaining a grommet holding structure relating to the present invention.
[Fig. 8]
Figs. 8(a) and 8(b) are views of the grommet holding structure of the present invention and a prior art grommet holding structure in a comparative example, respectively.

[Description of the Preferred Embodiments] Preferred embodiments of the present invention will be described with reference to the accompanying drawings, in which the drawings are to be observed with reference characters in an upright position.
Referring to Fig. 1 showing a motor scooter 1 relating to the present invention, the motor scooter 1 comprises a main frame 2, a head pipe 3 attached to a front end of the main frame 2, a front fork 4 supported in the head pipe 3, a front wheel 5 supported on the front fork 4, a power unit 10 pivotally supported on a rear part of the main frame 2 by a linkage 8 and a pivot shaft 9, and a rear wheel 12 supported by a rear axle 11 on a rear part of the power unit 10. Shown also in Fig. 1 are an exhaust system 14, a rear suspension 15, a seat 16, a cowl 17, an oil tank 18, a fuel tank 19, a headlight 21 and a CDI unit (condenser type ignition unit) 22. Aharness (wires), not shown, connecting
the CDI unit 22 to the power unit 10 is extended along the main frame 2.
Referring to Fig. 2 showing the power unit 10 relating to the present invention, the power unit 10 has a unit case
31 and a crankcase 32 supporting a crankshaft 33, and an
assembly of a cylinder 34 and a cylinder head 35. A piston
36 is fitted in the cylinder 34. A transmission pulley 37
is mounted on one end part of the crankshaft 33. A belt 38
is wound around the transmission pulley 37 and a driven
pulley 39 mounted on an intermediate shaft 41. Power is
transmitted from the intermediate shaft 41 through a
reduction gear train 42 to the rear axle 11. Indicated at
43 is a centrifugal clutch and at 44 is a unit case cover.
The other end part of the crank shaft 33 projects into a hollow 45 formed in the crankcase 32. A stator 47 and a rotor 48 included in a flywheel magneto 46 are disposed in the hollow 45 with the stator 47 attached to the crankcase
32 and the rotor 48 mounted on the crankshaft 33, an
air-cooling fan 51 is attached to the rotor 48, a fan cover
52, i.e., a covering member, covers the air-cooling fan 51,
a grille 53 is fitted in the fan cover 52.
The cover member 52 may be a crankcase cover.
The fan cover 52 is not a simple cover; the fan cover 52 has a volute chamber 55 for converting a dynamic pressure generated by the fan 51 into a corresponding static pressure,
and an air guide 56 for guiding pressurized air to the cylinder 34 and the cylinder head 35. The fan cover 52 extending to a position corresponding to an ignition plug 57 and a shroud 58 cover the cylinder 34 and the cylinder head 35.
Fig. 3 is a view showing the construction of the engine. The exhaust system 14 is seen from the right side of a rider in Fig. 1, in which the fan cover and such are removed from the crankcase 32.
The exhaust system 14 comprises a front exhaust pipe 14a, a large-diameter exhaust pipe 14b, a silencer 14c, a front bracket 14d and a rear bracket 14e. The front bracket 14d and the rear bracket 14e are fastened to the crankcase 32 with bolts 59a, 59b and 59c.
The hollow 45 of the crankcase 32 has a volute chamber 61 extending in a clockwise direction. The volute chamber 61 has an outlet opening toward the fins 62 of the cylinder 34, and the upper fins 63 and lower fins 64 of the cylinder head 35. A pulse signal sensor 70 is disposed at a starting end of the volute chamber 61. A structure for holding the pulse signal sensor 70 will be described later.
As is apparent from Fig. 3, the exhaust pipes 14a and
14b are extended in an angular range of about 180° around the hollow 45 of the crankcase 32 in which the pulse signal sensor 70 is disposed.
In the drawings, a structure comprising, as principal components, the crankcase 32, the crankshaft 33, the cylinder 34, the cylinder head 35, the stator 47, the rotor 48 and the pulse signal sensor 70 will be called "engine 75" herein.
A combination of the engine 75 with the exhaust system 14 will be called "engine unit 77" herein.
Fig. 4 is a side view of the cylinder head relating to the present invention. The cylinder head 35 is provided with the plurality of upper fins 63 and the plurality of lower fins 64. The area of heat transfer surface of the cylinder head 35 is far greater than that of a cylinder head provided with only upper fins and hence the cylinder head can satisfactorily be cooled.
Fig. 5 is a plan view of the cylinder head relating to the present invention. The upper fins 63 are inclined to the lower fins 64. Cooling air flows in the direction of the arrow (1). The upper fins 63 are inclined to the direction of flow of cooling air. The upper fins 63 thus inclined to the direction of flow of cooling air have an increased area of heat transfer, which increases the cooling effect of cooling air so that the cylinder head 35 can effectively be cooled.
Fig. 6 is an exploded perspective view of the engine unit relating to the present invention taken from the front
side of the body. One end part of the crankshaft 33 projects into the hollow 45 of the crankcase 32. The stator 47 is disposed in the hollow 45 and fastened to a wall defining the bottom of the hollow 42 with bolts B. The rotor 48 is fitted on and fastened with a nut 65 to the end part of the crankshaft 33. The fan 51 is fastened to the rotor 48 with bolts 66. The pulse signal sensor 70 is disposed at a predetermined position in the hollow 45 and is fastened to the crankcase 32 with two bolts 67 (only one of the two bolts 67 is shown) . An opening 68 and a grommet receiving recess 69 are formed in the crankcase 32 at a position near the pulse signal sensor 70. A grommet 80 is inserted in the grommet receiving recess 69, the fan cover 52 is put on and fastened with screws to the crankcase 32. A grommet holding tongue 52a is formed integrally with the fan cover 52. When the fan cover 52 is fastened to the crankcase 32, the grommet holding tongue 52a is inserted in the opening 68. The opening 68 and the grommet receiving recess 69 will be described in detail with reference to an enlarged view.
The grommet 80 is a sealing member for sealing a gap between a harness and an opening formed when extending the harness connected to an electric device contained in the case through the opening outside the case.
The air guide 56 formed integrally with an upper part of the fan cover 52 covers a right half of the assembly of the cylinder 34 and the cylinder head 35, and the shroud 58
covers the left half of the same.
Fig. 7 shows a grommet holding structure relating to the present invention. The grommet 80 has a base part provided with parallel grooves 81. The grommet 80 is inserted in the grommet receiving recess 69 in the direction
of the arrow (D so as to receive rails 69a in the grooves 81. The grommet holding tongue 52a is inserted in the
opening 68 in the direction of the arrow (D to press the grommet 80 in the direction of the arrow (4) so that the grommet 80 is held in the recess 69.
Since the grommet 80 is held in place by the grommet holding tongue 52a projecting from the covering member (fan cover 52), bolts or screws are unnecessary for fixing the grommet 80, which reduces the number of parts.
The rotor 48 is provided with a detecting member 72. The pulse signal sensor 70 senses the passage of the detecting member 72 past the pulse signal sensor 70.
Shown also in Fig. 7 are the axis L1 of the crankshaft, the axis L2 of the base part of the grommet 80, and an axis L3 coinciding with the axis L2 of the base part of the grommet 80 as inserted in the grommet receiving recess 69 . A harness 82 is extended through the grommet 80 in a direction substantially parallel to the axis L1 of the crankshaft. The harness 82 has wires connected to the pulse signal sensor 70 and the stator 47 (Fig. 6).
The direction of extension of a part of the harness
extending outside from the grommet 80 may be changed by an elbow 83.
Figs. 8 (a) and 8 (b) show the grommet holding structure of the present invention and a prior art grommet holding structure in a comparative example, respectively.
In Fig. 8 (a) , indicated at Dl is the distance between the axis of the cylinder and the outer end surface of the grommet, more specifically, between the axis of the cylinder and the outer surface of the grommet holding tongue 52a, and a circle 84 indicated by broken line represents the harness extended into the paper.
In the prior art grommet holding structure shown by way of example in Fig. 8(b), a grommet 101 is disposed on a radial line 102 passing the axis of a cylinder, and a harness 103 is extended radially outward through the grommet 101. Therefore, the distance D2 between the axis of the cylinder and the outer surface of the harness 103 is far greater than the distance D1. If the outer surface of the harness 103 is at the distance D2 from the axis of the cylinder, the accessories of the engine must be arranged so as not to interfere with the harness 103 and the exhaust system must be deflected from a straight line so as not to interfere with the harness 103, which makes the arrangement of the accessories and the exhaust system difficult. The grommet holding structure shown in Fig. 8 (a) facilitates the arrangement of the accessories of the engine and the exhaust system, and enables the disposition of the same close to the
crankcase.
According to claim 1, the disposition of the exhaust system is not specified and is optional. According to claim 3, the exhaust system is extended in an angular range of about 180° around the hollow of the crankcase. The exhaust system may be extended in an optional angular range, such as 90°, 150° or 210°, around the hollow of the crankcase.
Although the present invention is properly applied to a motor scooter provided with a power unit, the present invention may widely be applied to motorcycles, engines for portable sensors and general-purpose engines.
[Effect of the Invention]
According to claim 1, the harness is extended in a direction substantially parallel to a crankshaft. Therefore, the interference of the harness with devices arranged around the engine can easily be avoided as compared with a state in which the harness is extended radially outward. The radially outward projection of the harness is equivalent to increase in the size of the engine which makes the arrangement of the devices around the engine and the extension of the harness difficult. The technique stated in claim 1 solves such a problem, enables forming the engine in a compact construction and facilitates the arrangement of the devices around the engine and the extension of the harness.
According to claim 2, the grommet.is held in place with the grommet holding tongue extending from the covering member. Bolts or screws for fastening the grommet are unnecessary and hence the number of parts can be reduced.
According to claim 3, the harness is extended through the grommet in a direction substantially parallel to the crankshaft, and the exhaust system is disposed so as to surround the hollow defined by the crankcase. Therefore, in addition to the foregoing effect, the exhaust system can be extended without being interfered with by the harness, the exhaust system can be extended near the crankcase and the covering member, and the engine including the exhaust system can be formed in a compact construction.
[REFERENCE CHARACTERS]
1 Motor scooter, 10 Power unit,14 Ex-haust system, 14a, 14b Exhaust pipes,14c Silencer, 32Crankcase, 33 Crankshaft,45 Hollow in the crankcase,46 Flywheel magneto,47 Stator,48 Rotor,51 Air-cooling fan, 52 Covering member (fan cover),52a Grommet holding tongue, 68 Opening, 69 Grommet receiving recess, 69a Rail, 70 Pulse signal sensor,72 Detecting member,75 Engine, 77 Engine unit,80 Grommet, 81 Parallel grooves, 82 Harness



WE CLAIM:
1. A grommet holding structure on an engine having a crankcase (32), a
covering member (52), a flywheel magneto (46)consisting of a stator
(47) and a rotor (48) and disposed in a space defined by the crankcase
(32) and the covering member (52), a pulse signal sensor (70)disposed
in the space to monitor a detecting member attached to the outer
circumference of the rotor (48), a harness (82) including wires
connected to the pulse signal sensor (70) and the stator (47), and a
grommet (80) attached to the crankcase (32); characterized in that:
the grommet holding structure holds the
grommet (80) so that the harness (82) is extended therethrough in a direction substantially parallel to a crankshaft (33).
2. The grommet holding structure on an engine as claimed in claim 1,
wherein the crankcase (32) is provided with an opening extending in
parallel to the crankshaft (33), a grommet receiving recess (69) is
formed so as to extend from one end of the opening toward the
crankshaft (33), the grommet (80) is inserted in the grommet receiving
recess (69) from outside, a grommet holding tongue (52a) is extended
from the covering member (52) so that the grommet holding tongue
(52a) is inserted in the opening and holds the grommet to restrain the
grommet from radially outward movement.
3. The grommet holding structure on an engine as claimed in claim 1,
wherein the exhaust system (14a, 14b) is disposes so as to surround a
hollow defined by the crankcase (32).
4. A grommet holding structure on an engine substantially as
hereinbefore described with reference to and as illustrated in the
accompanying drawings.

Documents:

3862-del-1998-abstract.pdf

3862-del-1998-claims.pdf

3862-del-1998-correspondence-others.pdf

3862-del-1998-correspondence-po.pdf

3862-del-1998-description (complete).pdf

3862-del-1998-drawings.pdf

3862-del-1998-form-1.pdf

3862-del-1998-form-13.pdf

3862-del-1998-form-19.pdf

3862-del-1998-form-2.pdf

3862-del-1998-form-3.pdf

3862-del-1998-form-4.pdf

3862-del-1998-form-6.pdf

3862-del-1998-gpa.pdf

3862-del-1998-petition-137.pdf

3862-del-1998-petition-138.pdf


Patent Number 215382
Indian Patent Application Number 3862/DEL/1998
PG Journal Number 11/2008
Publication Date 14-Mar-2008
Grant Date 26-Feb-2008
Date of Filing 31-Dec-1998
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISA
Applicant Address 1-1 MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN.
Inventors:
# Inventor's Name Inventor's Address
1 TETSUAKI MAEDA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.
2 SHINJI KUGA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.
PCT International Classification Number F16C 5/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 Hei-10-036383 1998-02-18 Japan