A camshaft cover, a camshaft assembly, and a double-cylinder engine are provided. The camshaft cover has an integral structure, and includes a first shaft cover portion, a second shaft cover portion, a first connecting portion and a second connecting portion. The first connecting portion and the second connecting portion are connected between the first shaft cover portion and the second shaft cover portion, and spaced apart axially.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Chinese Patent Application No. 202020515152.6, filed on Apr. 9, 2020, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure relates to a technical field of engines, and particularly to a camshaft cover, a camshaft assembly, and a double-cylinder engine.

BACKGROUND

In the related art, a camshaft cover of an in-line double-cylinder engine generally is designed into a split structure. As shown inFIG. 5, the camshaft cover200includes a first part201, a second part202and a third part203. Although the parts are easy to shape after being produced independently, each part needs a mold and a clamp, which results in large development investment and a relatively complicated mounting process.

SUMMARY

The present disclosure seeks to solve at least one of the problems existing in the related art. To this end, an object of the present disclosure is to propose a camshaft cover for a double-cylinder engine, which has an integral structure and may reduce investment and assembling difficulties.

Embodiments of the present disclosure further propose a camshaft assembly for a double-cylinder engine.

Embodiments of the present disclosure further propose a double-cylinder engine.

The camshaft cover for the double-cylinder engine according to embodiments of the present disclosure has an integral structure, and includes a first shaft cover portion, a second shaft cover portion, a first connecting portion and a second connecting portion. The first connecting portion and the second connecting portion are connected between the first shaft cover portion and the second shaft cover portion, and spaced apart axially.

The camshaft assembly for the double-cylinder engine according to embodiments of the present disclosure includes: a first camshaft having an axis; a second camshaft having an axis parallel to the axis of the first camshaft; and a camshaft cover. The camshaft cover includes a first shaft cover portion, a second shaft cover portion, a first connecting portion and a second connecting portion which are integrally formed. The first connecting portion and the second connecting portion are spaced apart axially, and connected between the first shaft cover portion and the second shaft cover portion. The first shaft cover portion covers the first camshaft, and the second shaft cover portion covers the second camshaft.

The double-cylinder engine according to embodiments of the present disclosure includes a camshaft assembly. The camshaft assembly includes: a first camshaft having an axis; a second camshaft having an axis parallel to the axis of the first camshaft; and a camshaft cover. The camshaft cover has an integral structure, and includes a first shaft cover portion, a second shaft cover portion, a first connecting portion and a second connecting portion. The first connecting portion and the second connecting portion are connected between the first shaft cover portion and the second shaft cover portion, and spaced apart axially. The first shaft cover portion covers the first camshaft, and the second shaft cover portion covers the second camshaft.

DETAILED DESCRIPTION

Descriptions will be made in detail to embodiments of the present disclosure, and the embodiments described herein with reference to drawings are illustrative. Descriptions will be made in detail to embodiments of the present disclosure.

A camshaft assembly100according to an embodiment of the present disclosure will be described below with reference toFIGS. 1 to 4, and the camshaft assembly100may be applied to a double-cylinder engine which may be used in an all-terrain vehicle.

As shown inFIG. 1, the camshaft assembly100according to the embodiment of the present disclosure includes a first camshaft20, a second camshaft30and a camshaft cover10. The camshaft cover10is arranged on the first camshaft20and the second camshaft30, and may achieve protecting and fixing functions above the first camshaft20and the second camshaft30.

As shown inFIG. 1, the first camshaft20has at least two journals, for example, three journals, i.e., a first journal21, a second journal22and a third journal23, the second camshaft30has an axis parallel to an axis of the first camshaft20, both axes extend in a left-right direction, and the second camshaft30has at least two journals, for example, three journals, i.e., a fourth journal31, a fifth journal32and a sixth journal33. The journals and cams of the camshafts are alternated on both camshafts, for example, the journal may be connected between two cams. Specifically, the second journal22is connected between two cams, and the third journal23is also connected between two cams. For another example, the journal may also be connected to a side of the cam. Specifically, the first journal21is connected to a side of the cam. The first camshaft20may be configured as an exhaust camshaft, and the second camshaft30may be configured as an intake camshaft.

As shown inFIGS. 1 and 2, the camshaft cover10has an integral structure and includes a first shaft cover portion11, a second shaft cover portion12, a first connecting portion13and a second connecting portion14. The first connecting portion13and the second connecting portion14are connected between the first shaft cover portion11and the second shaft cover portion12, and are spaced apart axially. The first shaft cover portion11is arranged above the first camshaft20, and the second shaft cover portion12is arranged above the second camshaft30. It should be noted that a traditional camshaft cover generally has a split structure, while the camshaft cover10according to the present disclosure has the integral structure, thus achieving a good wholeness and a high structural strength. Further, a mold and a clamp for manufacturing the camshaft cover10have less investment, thus reducing an input cost. Moreover, an oil gallery15may also be conveniently arranged in the integral camshaft cover10.

As shown inFIG. 1, at least two shaft holes spaced apart axially are formed in a bottom of the first shaft cover portion11, the number of the shaft holes may be three, the three shaft holes may be a first shaft hole111, a second shaft hole112and a third shaft hole113, and the first shaft hole111, the second shaft hole112and the third shaft hole113may have the same size. At least two shaft holes spaced apart axially are formed in a bottom of the second shaft cover portion12, the number of the shaft holes may be three, the three shaft holes may be a fourth shaft hole121, a fifth shaft hole122and a sixth shaft hole123, and the fourth shaft hole121, the fifth shaft hole122and the sixth shaft hole123may have the same size.

The first journal21is engaged in the first shaft hole111, the second journal22is engaged in the second shaft hole112, the third journal23is engaged in the third shaft hole113, the fourth journal31is engaged in the fourth shaft hole121, the fifth journal32is engaged in the fifth shaft hole122, and the sixth journal33is engaged in the sixth shaft hole123. By properly configuring the shaft holes and the journals, the integral camshaft cover10can effectively protect and fix the first camshaft20and the second camshaft30, thus guaranteeing the structural reliability of the camshaft assembly100.

According to an optional embodiment of the present disclosure, as shown inFIGS. 1 and 2, the first connecting portion13is connected to an axial end of the first shaft cover portion11and an axial end of the second shaft cover portion12, i.e., the first connecting portion13is connected to a left end of the first shaft cover portion11and a left end of the second shaft cover portion12. Since transmission gears need to be arranged to the axial end of the first camshaft20and the axial end of the second camshaft30, the arrangement of the first connecting portion13to the axial end of the first shaft cover portion11and the axial end of the second shaft cover portion12may facilitate a fixed mounting of the first camshaft20and the second camshaft30, and guarantee the transmission stability between the two camshafts and a crankshaft of an engine.

Further, as shown inFIGS. 1 to 4, the oil gallery15is arranged in the camshaft cover10, and oil holes16in communication with the oil gallery15are provided at the at least two shaft holes. Specifically, the oil holes16in communication with the oil gallery15are formed at the first shaft hole111, the second shaft hole112, the third shaft hole113, the fourth shaft hole121, the fifth shaft hole122and the sixth shaft hole123. That is, each shaft hole is correspondingly provided with one oil hole16, and the oil hole16may provide a lubricating oil for the corresponding shaft hole, thereby guaranteeing lubrication of the journals, and then guaranteeing the working reliability of the camshaft assembly100. The oil gallery15may be conveniently arranged in the integral camshaft cover10, and may supply oil to at least two oil holes16at the same time, such that the camshaft cover10has a simple structure, and the lubrication of the first camshaft20and the second camshaft30can be guaranteed. A projection of the oil hole16in a plane perpendicular to the camshafts or the camshaft cover10may have an arc shape, which matches with a shape of a surface of the corresponding journal, and thus the arc-shaped oil hole16may facilitate the oil supply to the surfaces of the journals.

Specifically, as shown inFIGS. 2 to 4, the oil gallery15includes a first sub-oil gallery151, a second sub-oil gallery152and a third sub-oil gallery153, the first sub-oil gallery151extends throughout the first shaft cover portion11, the first connecting portion13and the second shaft cover portion12, and an oil inlet of the first sub-oil gallery151may be arranged on a side of the first shaft cover portion11, so as to facilitate an oil intake. At least two third sub-oil galleries153are provided and in communication with the oil holes16of at least two corresponding shaft holes. The second sub-oil gallery152arranged at the first shaft cover portion11is in communication with multiple third sub-oil galleries153of the first shaft cover portion11, and the second sub-oil gallery152arranged at the second shaft cover portion12is in communication with at least two third sub-oil galleries153of the second shaft cover portion12. The third sub-oil galleries153of the first shaft cover portion11and the second shaft cover portion12adjacent to the first connection portion13are communicated with the first sub-oil gallery151.

Specifically, six third sub-oil galleries153are provided and in communication with the six oil holes16, respectively. The first sub-oil gallery151is in direct communication with the third sub-oil gallery153located at the first shaft hole111, and is in direct communication with the third sub-oil gallery153located at the fourth shaft hole121. Two second sub-oil galleries152are provided and arranged at the first shaft cover portion11and the second shaft cover portion12, respectively. The second sub-oil gallery152arranged at the first shaft cover portion11is in communication with the three third sub-oil galleries153of the first shaft cover portion11, and the second sub-oil gallery152arranged at the second shaft cover portion12is in communication with the three third sub-oil galleries153of the second shaft cover portion12.

It may be understood that after the lubricating oil inside the engine is supplied to the first sub-oil gallery151, the first sub-oil gallery151may supply the oil to the third sub-oil gallery153corresponding to the first haft hole111and to the third sub-oil gallery153corresponding to the fourth shaft hole121, the third sub-oil gallery153at the first shaft hole111may supply the oil to the third sub-oil gallery153at the second shaft hole112and the third sub-oil gallery153at the third shaft hole113through the second sub-oil gallery152in the first shaft cover portion11, and the third sub-oil gallery153at the fourth shaft hole121may supply the oil to the third sub-oil gallery153at the fifth shaft122and the third sub-oil gallery153at the sixth shaft hole123through the second sub-oil gallery152in the second shaft cover portion12, thereby guaranteeing lubrication of the six journals, and further guaranteeing the lubricating effect of the camshaft assembly100.

Thus, the integral structure of the camshaft cover10may facilitate the arrangement of oil paths, and the oil gallery15and the oil hole16in communication with each other may be directly formed in the integral camshaft cover10, which simultaneously meets the lubricating effects between the first camshaft20and various parts as well as between the second camshaft30and various parts.

In some embodiments, as shown inFIG. 2, the second connecting portion14has an end connected between the second shaft hole112and the third shaft hole113of the first shaft cover portion11, and another end connected between the fifth shaft hole122and the sixth shaft hole123of the second shaft cover portion12. The second connecting portion14may have the function of connecting the first shaft cover portion11with the second shaft cover portion12, and the first connecting portion13and the second connecting portion14are spaced apart axially, such that a closed-loop structure of connection may be formed throughout the first connecting portion13, the first shaft cover portion11, the second connecting portion14and the second shaft cover portion12, thereby further improving the structural reliability of the camshaft cover10.

According to an embodiment of the present disclosure, as shown inFIG. 1, the first camshaft20is provided with a first shaft shoulder24on a side of the first journal21facing away from the second journal22, and the second camshaft30is provided with a second shaft shoulder34on a side of the fourth journal31facing away from the fifth journal32. The first shaft cover portion11is provided with a first position limiting groove114, the second shaft cover portion12is provided with a second position limiting groove124, the first shaft shoulder24is engaged in the first position limiting groove114, and the second shaft shoulder34is engaged in the second position limiting groove124. By the engagement of the first shaft shoulder24and the first position limiting groove114as well as the engagement of the second shaft shoulder34and the second position limiting groove124, the first camshaft20and the second camshaft30may be limited axially, thereby guaranteeing the axial stability of the first camshaft20and the second camshaft30.

Further, as shown inFIG. 1, the first camshaft20is provided with a first flange25on a side of the first shaft shoulder24facing away from the first journal21, the first flange25and the first shaft shoulder24have a spacing B therebetween, the second camshaft30is provided with a second flange35on a side of the second shaft shoulder34facing away from the fourth journal31, the second flange35and the second shaft shoulder34have a spacing A therebetween, and A≠B. That is, there exists a fool-proof design between the first camshaft20and the second camshaft30, thereby preventing a misassembling problem, and guaranteeing the reliability of achieving the functions of the engine. In addition, the manner of changing the spacing to prevent misassembling is easy to realize.

Still further, as shown inFIG. 1, the first position limiting groove114and the second position limiting groove124have an axial spacing C therebetween, and C=|B−A|. Thus, in the camshaft assembly100according to the present disclosure, on the basis of reasonably designing the two camshafts, the spacing between the two position limiting grooves on the camshafts is also designed reasonably, such that the second shaft shoulder34can be just engaged in the second position limiting groove124when the first shaft shoulder24is just engaged in the first position limiting groove114, thereby further improving the engagement accuracy and reliability of the camshaft assembly100. The first position limiting groove114and the second position limiting groove124may have the same shape and structure.

In some embodiments, as shown inFIGS. 1 and 2, a first position limiting protrusion115is provided at an end of the second shaft hole115adjacent to the first shaft hole111, and a second position limiting protrusion125is provided at an end of the fifth shaft hole122adjacent to the sixth shaft hole123. The arrangement of the first position limiting protrusion115and the second position limiting protrusion125may achieve an axial position limiting function, and guarantee the axial engagement stability between the first shaft cover portion11and the first camshaft20, and the axial engagement stability between the second shaft cover portion12and the second camshaft30. In addition, the staggered arrangement of the first position limiting protrusion115and the second position limiting protrusion125may achieve the function of preventing misassembling at least to some extent, thus further improving the reliability of the camshaft assembly100.

Specifically, as shown inFIG. 1, the second journal22has a first end face adjacent to the first journal21and a second end face facing away from the first journal21, and the fifth journal32has a first end face adjacent to the fourth journal31and a second end face facing away from the fourth journal31. The first position limiting protrusion115and the first end face of the second journal22have a distance F therebetween, and the first position limiting protrusion115and the first end face of the fifth journal32also have a distance F therebetween. The second position limiting protrusion125and the second end face of the second journal22have a distance D therebetween, and the second position limiting protrusion125and the second end face of the fifth journal32also have a distance therebetween. 0<F<C, and 0<D<C. The camshaft assembly100arranged in this way may further achieve the function of preventing misassembling, thus guaranteeing the assembling accuracy.

Thus, when the first camshaft20and the second camshaft30are correctly assembled into the camshaft cover10, that is, when the first shaft shoulder24is assembled into the first position limiting groove114, the first, second and third journals21,22,23are correspondingly assembled into the first, second and third shaft holes111,112,113, respectively, the second shaft shoulder34is assembled into the second position limiting groove124, and the fourth, fifth and sixth journals31,32,33are correspondingly assembled into the fourth, fifth and sixth shaft holes121,122,123, respectively. An axial distance between the first end face of the second journal22and an end face of the first position limiting protrusions115is the distance F, and an axial distance between the second end face of the second journal22and an end face of the second position limiting protrusions125is the distance D. An axial distance between the first end face of the fifth journal32and the end face of the first position limiting protrusion115is the distance F, and an axial distance between the second end face of the fifth journal32and the end face of the second position limiting protrusion125is the distance D. 0<F<C, 0<D<C. The camshafts do not interfere with the first position limiting protrusion115when working.

When the first shaft shoulder24of the first camshaft20is to be assembled into the second position limiting groove124, the first camshaft20is axially moved by a distance C in a direction from the third journal23to the first journal21, in which 0<D<C. and hence the second end face of the second journal22will interfere with the second position limiting protrusion125during assembling, thus effectively preventing misassembling of the first camshaft20.

When the second shaft shoulder34of the second camshaft30is to be assembled into the first position limiting groove114, the second camshaft30is axially moved by a distance C in a direction from the fourth journal31to the sixth journal33, in which 0<F<C, and hence the first end face of the fifth journal32will interfere with the first position limiting protrusion115during assembling, thus effectively preventing misassembling of the second camshaft30.

A double-cylinder engine according to an embodiment of the present disclosure includes the camshaft assembly100according to the above embodiments.

An all-terrain vehicle according to an embodiment of the present disclosure includes the double-cylinder engine according to the above embodiment.

In the descriptions of the present disclosure, it is to be understood that terms such as “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “anticlockwise”, “axial”, “radial”, and “circumferential” should be construed to refer to the orientation and position as shown in the drawings. These relative terms are for convenience of descriptions and do not indicate or imply that the device or element must be constructed or operated in a particular orientation, thus cannot be construed to limit the present disclosure.

In the descriptions of the present disclosure, the feature defined with “first” and “second” may include one or more of this feature. In the descriptions of the present disclosure, “a plurality of” means two or more. In the descriptions of the present disclosure, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact but contacted via an additional feature formed therebetween. In the descriptions of the present disclosure, a first feature being “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature.

In the descriptions of the present specification, reference throughout this specification to “an embodiment”, “some embodiments”, “illustrative embodiment”, “example”, “specific example” or “some examples” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In the specification, the schematic expressions related to the above terms do not necessarily refer to the same embodiment or example.

Although embodiments of the present disclosure have been shown and illustrated, it shall be understood by those skilled in the art that various changes, modifications, alternatives and variants can be made without departing from the principle and idea of the present disclosure. The scope of the present disclosure is defined by claims and their equivalents.