EP2657496B1

EP2657496B1 - Engine and Saddle-Ride Type Vehicle

Info

Publication number: EP2657496B1
Application number: EP12185820.3A
Authority: EP
Inventors: Kensuke Yamamoto
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2012-04-27
Filing date: 2012-09-25
Publication date: 2015-11-25
Anticipated expiration: 2032-09-25
Also published as: JP2013231385A; ES2555281T3; EP2657496A1

Description

TECHNICAL FIELD

The present invention relates to an engine including a cylinder head cover and a saddle-ride type vehicle.

BACKGROUND ART

EP1310637 A2 discloses an engine according to the preamble of claim 1.
A method of forming a recess on a cylinder head cover side end portion of a cylinder head for accommodating a camshaft has been proposed so far in order to enhance the maintenance performance of the camshaft (see Japan Laid-open Patent Application Publication No. JP-A-2008-025451 ). In the publication No. JP-A-2008-025451 , a seal member to be fitted into the recess of the cylinder head is attached to the cylinder head cover.
However, the method of the publication No. JP-A-2008-25451 has a drawback that noise is produced from an engine due to vibration of the seal member fitted into the recess of the cylinder head.
It is an object of the present invention to inhibit engine noise.

SUMMARY

According to the invention, an engine according to claim 1 and a saddle-ride type vehicle according to claim 6 are provided.
According to the engine of the present invention, it is possible to reduce vibration to be caused by minute undulation and/or torsion of the convex portion. Therefore, noise can be inhibited from being produced from the engine. Further, the convex portion is integrally formed with the cover main body. The cylinder head cover can be thereby manufactured using, for instance, a casting mold. Therefore, it is possible to reduce the number of manufacturing steps and manufacturing cost, compared to the case that the cover member and the convex portion are separately fabricated.
Preferably at least either of the second and third ribs is extended on the lateral surface from the first rib to the opposite side of the convex portion.
The first rib can be rigidly supported by the second and third ribs. Therefore, vibration of the convex portion can be further reduced.
Preferably the convex portion portion includes first and second end portions in the first direction. The second rib is disposed on an opposite side of the first end portion through the first rib. The third rib is disposed on an opposite side of the second end portion through the first rib.
Both of the end portions of the convex portion can be rigidly fixed. Therefore, vibration of the convex portion can be further reduced.
Preferably the convex portion has a semi-circular shape in a plan view of the lateral surface.
Preferably the first, second and third ribs are respectively integrally formed with the cover main body.
The first to third ribs can be fabricated together with the cover main body using, for instance, a casting mold. Therefore, it is possible to reduce the number of manufacturing steps and manufacturing cost, compared to the case that the cover main body and the first to third ribs are separately fabricated.
A saddle-ride type vehicle comprising an engine according to claim 1 and a vehicle body frame configured to support the engine is defined in claim 6.
Overall, according to the present invention, it is possible to provide an engine and a saddle-ride type vehicle whereby noise production can be inhibited.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of this original disclosure:

FIG 1 is a side view of a saddle-ride type vehicle 1;
FIG 2 is a cross-sectional view of an engine unit sectioned along a horizontal plane;
FIG 3 is a cross-sectional view of the engine unit sectioned along a vertical plane;
FIG 4 is a side view of a structure of a cylinder head;
FIG. 5 is a side view of a structure of a cylinder head cover;
FIG. 6 is a perspective view of the structure of the cylinder head cover;
FIG 7 is a side view of another structure of the cylinder head cover; and
FIG 8 is a side view of yet another structure of the cylinder head cover

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, an exemplary embodiment of the present invention will be explained using figures. In the following description of the figures, the same or similar reference numeral is given to the same or similar elements. It should be noted that the figures are schematic only and respective dimensional ratios and etc. of the figures may be different from actual ones. Therefore, specific dimensions and etc. should be judged in view of the following explanation. Further, it is apparent that dimensional relations and ratios of corresponding parts/portions/sections are different among the figures.

(Schematic Structure of Saddle-Ride Type Vehicle 1)

A schematic structure of a saddle-ride type vehicle 1 according to an exemplary embodiment of the present invention will be hereinafter explained with reference to the figures. It should be noted in the present exemplary embodiment that "a back-and-forth direction" refers to a vehicle longitudinal direction seen from a rider seated on a seat 5 to be described unless particularly explained. "A right-and-left direction" refers to a vehicle transverse direction seen from a rider seated on the seat 5. "An up-and-down direction" refers to a vertical direction.
FIG 1 is a side view of the saddle-ride type vehicle 1 according to the present exemplary embodiment. The saddle-ride type vehicle I is a scooter-type motorcycle. The saddle-ride type vehicle 1 includes a vehicle body 2, a front fork 3, a front wheel 4, the seat 5, an engine unit 6 and a rear wheel 7.
The vehicle body 2 includes a vehicle body frame and a vehicle body cover. The vehicle body frame supports the engine unit 6, whereas the vehicle body cover covers the vehicle body frame. The front fork 3 supports the front wheel 4 in a rotatable state. The seat 5 is disposed on the vehicle body 2 while being disposed behind the front fork 3.
The engine unit 6 is disposed under the seat 5. The engine unit 6 is pivotably supported by the vehicle body frame through a bracket (not illustrated in the figures). The engine unit 6 includes an engine 10 and a transmission case 20. In the present exemplary embodiment, a water-cooled 4-cycle single-cylinder SOHC (Single OverHead Camshaft) engine is exemplified as the engine 10. However, any type of SOHC engine may be employed as the engine 10. The transmission case 20 supports the rear wheel 7 in a rotatable state.

(Structure of Engine Unit 6)

Next, a structure of the engine unit 6 will be explained with reference to the figures. FIG. 2 is a cross-sectional view of the engine 10 sectioned along a horizontal plane. FIG 3 is a cross-sectional view of the engine unit 6 where the engine 10 is sectioned along a vertical plane.
The engine 10 includes a crankcase 11, a power generator 12, a crankshaft 13, a cylinder body 14, a piston 15, a connecting rod 16, a cylinder head 17, a cylinder head cover 18 and a valve train mechanism 19. Further, the transmission case 20 accommodates a V-belt automatic transmission 21, a centrifugal clutch 22 and a gear reducer 23.
The crankcase 11 is disposed in front of the rear wheel 7 while being coupled to the right side of the front end portion of the transmission case 20. The crankcase 11 accommodates the crankshaft 13.
The power generator 12 is disposed on the right side of the crankcase 11. The power generator 12 is configured to generate power by means of rotational force of the crankshaft 13.
The crankshaft 13 is disposed within the crankcase 11 along the right-and-left direction. The right end portion of the crankshaft 13 is coupled to the power generator 12, while the left end portion of the crankshaft 13 is coupled to the V-belt automatic transmission 21. Further, a driving sprocket 13a is attached to the crankshaft 13. A cam chain 14a to be described is wound about the driving sprocket 13a. The rotational force of the crankshaft 13 is transmitted to the rear wheel 7 through the V-belt automatic transmission 21, the centrifugal clutch 22 and the gear reducer 23 while being transmitted to the cam chain 14a through the driving sprocket 13a.
The cylinder body 14 is coupled to the front side of the crankcase 11. The cylinder body 14 accommodates the piston 15 and the connecting rod 16. The piston 15 is supported within the cylinder body 14 while being movable in a reciprocatory manner. The connecting rod 16 is coupled to the piston 15 and the crankshaft 13. The reciprocatory action of the piston 15 is transmitted to the crankshaft 13 through the connecting rod 16. Further, a cam chain compartment 14S is formed within the cylinder body 14 for accommodating the cam chain 14a. The rear end portion of the cam chain 14a is wound about the driving sprocket 13a, while the front end portion of the cam chain 14a is wound about a driven sprocket 19b to be described.
The cylinder head 17 is coupled to the front side of the cylinder body 14. The cylinder head cover 18 is coupled to the front side of the cylinder head 17. A cam compartment 19S is formed within the cylinder head 17 and the cylinder head cover 18 for accommodating the valve train mechanism 19. The cam compartment 19S is an exemplary "space formed between a cylinder head and a cylinder cover". A structure of the cylinder head 17 and that of the cylinder head cover 18 will be described below.
The valve train mechanism 19 includes a camshaft 19a and the driven sprocket 19b. The camshaft 19a is disposed along the right-and-left direction. The driven sprocket 19b is attached to the left end portion of the camshaft 19a. The cam chain 14a is wound about the driven sprocket 19b.

(Structure of Cylinder Head 17)

Next, a structure of the cylinder head 17 will be explained with reference to the figures. FIG 4 is a side view of the structure of the cylinder head 17.
The cylinder head 17 has a cylinder body lateral end portion 171, a cover lateral end portion 172, a recessed portion 173, a lateral surface 174 and a flanged portion 175.
The cylinder body lateral end portion 171, corresponding to the rear end portion of the cylinder head 17, is coupled to the cylinder body 14. The cover lateral end portion 172, corresponding to the front end portion of the cylinder head 17, is coupled to the cylinder head cover 18.
The recessed portion 173 is formed on the cover lateral end portion 172. The recessed portion 173 is formed by partially cutting out the front end of the lateral surface 174. The recessed portion 173 is formed with an appropriate size in an appropriate position for making the camshaft 19a viewable from the outside of the cylinder head 17. In the present exemplary embodiment, the camshaft 19a is roughly entirely positioned inside the recessed portion 173 in a side view of the cylinder head 17. Therefore, the camshaft 19a can be pulled out to the outside from the recessed portion 173. It should be noted that the structure of the recessed portion 173 is not limited to the above. The recessed portion 173 is only required to be formed for making the camshaft 19a at least partially viewable in a side view of the cylinder head 17. In other words, as illustrated in FIG 4, the camshaft 19a is only required to be partially positioned within a viewable region r arranged between a front end line R1 indicating the front end of the recessed portion 173 and a rear end line R2 indicating the rear end of the recessed portion 173. Further, the recessed portion 173 is more preferably formed for making the driven sprocket 19b viewable from the outside of the cylinder head 17. With the recessed portion 173 structured as described above, easy and convenient access to the camshaft 19a, the driven sprocket 19b and the cam chain 14a can be implemented in executing a maintenance work of the valve train mechanism 19.
The lateral surface 174 is a surface arranged roughly perpendicularly to the extended direction of the camshaft 19a (i.e., the right-and-left direction) and forms a part of the outer peripheral surface of the cylinder head 17. Therefore, an end of the camshaft 19a is disposed inside the recessed portion 173 as illustrated in FIG 4.
The flanged portion 175 is formed along the front end of the cover lateral end portion 172. The flanged portion 175 is coupled to the cylinder head cover 18 through a gasket to be described.

(Structure of Cylinder Head Cover 18)

Next, a structure of the cylinder head cover 18 will be explained with reference to the figures. FIG 5 is a side view of the structure of the cylinder head cover 18. FIG 6 is a perspective view of the structure of the cylinder head cover 18.
The cylinder head cover 18 has a cover main body 181, a convex portion 182, a first rib 185, a second rib 186 and a third rib 187.
The cover main body 181 is a lid-shaped member to be put on the cylinder head 17. The cover main body 181 has a flanged portion 181a, a lateral surface 183 and an opposed surface 184. The flanged portion 181 a is fitted to the flanged portion 175. The gasket (not illustrated in the figures) is attached to the inside of the flanged portion 181a. The lateral surface 183 is a surface arranged roughly perpendicularly to the right-and-left direction and forms a part of the outer peripheral surface of the cover main body 181. Therefore, the lateral surface 183 is arranged roughly in parallel to the lateral surface 174 of the cylinder head 17. The opposed surface 184 is a surface opposed to the cylinder head 17. In a side view, the position of the opposed surface 184 is matched with that of a boundary line R5 indicating a boundary T.
The convex portion 182 has a semi-circular shape while being protruded towards the cylinder head 17 from the cover main body 181. The convex portion 182 is fitted into the recessed portion 173 of the cylinder head 17. In other words, the convex portion 182 functions as a cover for closing the recessed portion 173. In the present exemplary embodiment, the convex portion 182 is integrally formed with the cover main body 181 (specifically, the flanged portion 181a). FIG 5 depicts an upper end line R3 indicating an upper end 182a (an exemplary first end portion) of the convex portion 182, a lower end line R4 indicating a lower end portion 182b (an exemplary second end portion) of the convex portion 182, and the boundary line R5 indicating the boundary T between the cover main body 181 and the convex portion 182.
The first rib 185 is disposed on the lateral surface 183 of the cover main body 181. The first rib 185 is extended in the up-and-down direction (an exemplary first direction) along the boundary T between the cover main body 181 and the convex portion 182. In the present exemplary embodiment, the first rib 185 is entirely formed on the lateral surface 183 in the up-and-down direction. Therefore, the upper end of the first rib 185 is upwardly extended across the second rib 186, whereas the lower end of the first rib 185 is downwardly extended across the third rib 187. It should be noted in the present exemplary embodiment that the first rib 185 is integrally formed with the cover main body 181.
The second rib 186 is disposed on the lateral surface 183 of the cover main body 181. The second rib 186 is coupled to the first rib 185 on the opposite side of the convex portion 182 through the first rib 185. The second rib 186 is extended from the first rib 185 to the opposite side of the convex portion 182 (i.e., to the forward). The second rib 186 has a rectangular outer contour in a side view. The second rib 186 is disposed perpendicularly to the first rib 185 in a side view. Further, the second rib 186 is disposed on the opposite side of the upper end portion 182a of the convex portion 182. Therefore, the second rib 186 is overlapped with the upper end line R3 indicating the upper end portion 182a of the convex portion 182 in a side view.
The third rib 187 is disposed on the lateral surface 183 of the cover main body 181. The third rib 187 is coupled to the first rib 185 on the opposite side of the convex portion 182 through the first rib 185. The third rib 187 is extended from the first rib 185 to the opposite side of the convex portion 182 (i.e., to the forward). The third rib 187 has a rectangular outer contour in a side view. The third rib 187 is disposed perpendicularly to the first rib 185 in a side view. Further, the third rib 187 is disposed on the opposite side of the lower end portion 182b of the convex portion 182. Therefore, the third rib 187 is overlapped with the lower end line R4 indicating the lower end portion 182b of the convex portion 182 in a side view.

(Actions and Effects)

(1) The cylinder head cover 18 according to the present exemplary embodiment has the cover main body 181, the convex portion 182, the first rib 185, the second rib 186 and the third rib 187. The first rib 185 is extended in the up-and-down direction (an exemplary first direction) along the boundary T between the cover main body 181 and the convex portion 182. Each of the second and third ribs 186 and 187 is coupled to the first rib 185 on the opposite side of the convex portion 182 through the first rib 185.
Therefore, it is possible to reduce vibration to be produced by minute undulation and/or torsion of the convex portion 182. As a result, noise can be inhibited from being produced from the engine 10.
Further, in the cylinder head cover 18 according to the present exemplary embodiment, the convex portion 182 is integrally formed with the cover main body 181.
Therefore, the cylinder head cover 18 can be manufactured using, for instance, a casting mold. As a result, it is possible to further reduce the number of manufacturing steps and manufacturing cost compared to the case that the cover main body 181 and the convex portion 182 are separately fabricated.
(2) The second and third ribs 186 and 187 are respectively extended from the first rib 185 to the opposite side of the convex portion 182.
Therefore, the first rib 185 can be rigidly supported by the second and third ribs 186 and 187. As a result, vibration of the convex portion 182 can be further reduced.
(3) The second rib 186 is disposed on the opposite side of the upper end portion 182a (an exemplary first end portion) of the convex portion 182, whereas the third rib 187 is disposed on the opposite side of the lower end portion 182b (an exemplary second end portion) of the convex portion 182.
Therefore, the both end portions of the convex portion 182 can be rigidly fixed. As a result, vibration of the convex portion 182 can be further reduced.
(4) The first rib 185, the second rib 186 and the third rib 187 are respectively integrally formed with the cover main body 181.
Therefore, the first to third ribs 185 to 187 can be fabricated together with the cover main body 181 using, for instance, a casting mold. As a result, it is possible to further reduce the number of manufacturing steps and manufacturing cost compared to the case that the cover main body 181 and the first to third ribs 185 to 187 are separately fabricated.

(Other Exemplary Embodiments)

The present invention has been described with the aforementioned exemplary embodiment. However, it should not be understood that the description and figures, forming a part of this disclosure, are intended to limit the present invention. A variety of alternative exemplary embodiments, practical examples and operational techniques would be apparent for those skilled in the art within the scope of the appended claims.
(A) In the aforementioned exemplary embodiment, the first rib 185 is entirely formed on the lateral surface 183 in the up-and-down direction. However, the structure of the first rib 185 is not limited to the above. For example, as illustrated in FIG 7, the first rib 185 may be disposed between the second rib 186 and the third rib 187.
(B) In the aforementioned exemplary embodiment, each of the second and third ribs 186 and 187 has a rectangular outer contour in a side view. However, the outer contours of the second and third ribs 186 and 187 are not limited to the above. For example, the outer contours of the second and third ribs 186 and 187 can be set to be in arbitrary shapes such as a circular shape (including a semi-circular shape and etc.) and a triangular shape (including an isosceles triangular shape, a right triangular shape and etc.) as illustrated in FIG 8.
Further, the second and third ribs 186 and 187 are respectively disposed perpendicularly to the first rib 185 in a side view. However, the arrangements of the second and third ribs 186 and 187 are not limited to the above. The second and third ribs 186 and 187 may be disposed obliquely to the first rib 185 in a side view.
(C) In the aforementioned exemplary embodiment, each of the recessed portion 173 and the convex portion 182 has an outer contour of a semi-circular shape in a side view. However, the shapes of the recessed portion 173 and the convex portion 182 are not limited to the above. Each of the recessed portion 173 and the convex portion 182 can be set to have an outer contour of an arbitrary shape such as a triangular shape, a square shape or etc.
(D) In the aforementioned exemplary embodiment, the arrangements of the respective members have been explained using terms of the back-and-forth direction, the right-and-left direction and the up-and-down direction. However, the arrangements of the members are not limited to those set in the aforementioned exemplary embodiment. For example, the engine 10 may not be disposed along the back-and-forth direction. The crankshaft 13 may not be disposed along the right-and-left direction. Thus, the arrangements of the respective members can be changed depending on the entire structure of the saddle-ride type vehicle 1.
(E) In the aforementioned exemplary embodiment, the scooter-type motorcycle has been explained as an exemplary saddle-ride type vehicle. However, the saddle-ride type vehicle is not limited to the above. The saddle-ride type vehicle may include an all-terrain vehicle, a snowmobile and etc. other than the motorcycle. Further, the motorcycle may include an off-road motorcycle, an on-road motorcycle, a moped and etc. other than the scooter-type motorcycle.

Industrial Applicability

According to the present invention, engine noise can be inhibited. Therefore, the present invention is useful in the field of engines and the field of saddle-ride type vehicles.

Reference Signs List

1: Saddle-ride type vehicle
2: Vehicle body
6: Engine unit
10: Engine
11: Crankcase
12: Power generator
13: Crankshaft
14: Cylinder body
15: Piston
16: Connecting rod
17: Cylinder head
173: Recessed portion
18: Cylinder head cover
182: Convex portion
185: First rib
186: Second rib
187: Third rib
19: Valve train mechanism
19a: Camshaft
19b: Driven sprocket

Claims

An engine (10) comprising:
a crankcase (11) configured to accommodate a crankshaft (13);

a cylinder body (14) coupled to the crankcase (11);

a cylinder head (17) coupled to the cylinder body (14);

a cylinder head cover (18) coupled to the cylinder head (17); and

a camshaft (19a) disposed in a space between the cylinder head (17) and the cylinder head cover (18),

the cylinder head (17) including a recessed portion (173) formed on a cylinder head cover side end of the cylinder head (17), and the camshaft (19a) being roughly entirely positioned inside the recessed portion (173) in a side view of the cylinder head (17),

characterized by the cylinder head cover (18) including a cover main body (181), a convex portion (182), a first rib (185), a second rib (186) and a third rib (187),

the cover main body (181) covering the cylinder head (17),

the convex portion (182) fitted into the recessed portion (173), the convex portion (182) protruded from the cover main body (181) towards the cylinder head (17), the convex portion (182) integrally formed with the cover main body (181),

the first rib (185) extended in a first direction, the first rib (185) formed on an outer lateral surface of the cover main body (181) along a boundary between the cover main body (181) and the convex portion (182),

the second (186) and third ribs (187) connected on the outer lateral surface to the first rib (185)

on an opposite side of the convex portion (182) through the first rib (185).
The engine (10) according to claim 1, wherein
at least either of the second (186) and third ribs (187) is extended on the lateral surface from the first rib (185) to the opposite side of the convex portion (182).
The engine (10) according to one of the claims 1 to 2, wherein
the convex portion (182) includes a first end portion (182a) and a second end portion (182b) in the first direction,
the second rib (186) is disposed on an opposite side of the first end portion (182a) through the first rib (185), and
the third rib (187) is disposed on an opposite side of the second end portion (182b) through the first rib (185).
The engine (10) according to one of the claims 1 to 3, wherein
the convex portion (182) has a semi-circular shape in a plan view of the lateral surface.
The engine (10) according to one of the claims 1 to 4, wherein
the first rib (185), the second rib (186) and the third rib (187) are respectively integrally formed with the cover main body (181).
A saddle-ride type vehicle (1) comprising:
the engine (10) according to one of the claims 1 to 5; and

a vehicle body frame (2) configured to support the engine (10).