JPS6233922Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a camshaft positioning mechanism that prevents displacement of the engine camshaft and deformation of the locating plate.

In a reciprocating engine, an intake valve and an exhaust valve are opened and closed by a camshaft that rotates in conjunction with a crankshaft via a gear train or the like. This camshaft is rotatably supported by the cylinder block, and the cam surface provided around it is an important part that drives the opening and closing of the valve, so it is necessary to ensure its positioning and end play in the axial direction of the camshaft. must be done reliably.

In this case, the camshaft is positioned in the axial direction by engaging a locating plate, which is fixed to the cylinder block together with the gasket and the end plate, to the side surface of the journal portion of the camshaft.

FIG. 1 is a cross-sectional view of a main part showing an example of a camshaft positioning mechanism commonly used in the past. A hole 2 is formed in a cylinder block 1, and a camshaft 3 is inserted into the hole 2.
4, and the journal portion 4 is rotatably supported. On the other hand, cylinder block 1
A gasket 5 and an end plate 6, which pass through the journal part 4 of the camshaft 3, are provided on the end face of the camshaft 3. A hole 7 having a diameter slightly smaller than the outer diameter of the journal part 4 is formed from the outside of the gasket 5.
A locating plate 8 passing through the shaft end of the locating plate 8 is fastened together with a bolt 9. Therefore, the locating plate 8 engages with the side surface of the journal portion 4 provided on the camshaft 3 to position the camshaft 3 in the axial direction. A gear 10 for driving the camshaft is attached to the outer end of the camshaft 3 whose axial position is regulated in this way. In this case, the gear 10 has an outer diameter reduced boss portion 11 that escapes the thickness of the locating plate 8 on the cylinder block 1 side.
The outer diameter reduced boss portion 11 passes through the hole 7 of the locating plate 8 and is pressed against the side surface of the journal portion 4, securing a regular end plate that is tightened and fixed with a nut 12. It's becoming like that. Note that 15 is a key inserted into the keyway of the camshaft 3 and the gear 10, and positions the camshaft 3 and the gear 10 in the rotational direction.

In the camshaft positioning mechanism configured in this way, axial positioning is performed by the side surface of the journal part 4 provided on the camshaft 3 engaging with the side surface of the locating plate 8, and the rotation of the crankshaft is performed as shown in the figure. As a result, the camshaft 3 keyed to the gear 10 is rotated, and the intake and exhaust valves are opened and closed.

However, in the above configuration, since the locating plate 8 is fastened together with the gasket 5 and the end plate 6 to the cylinder block 1, the amount of deformation of the gasket 5 becomes uneven, and the end plate 6 and the locating plate 8 As the image becomes distorted, its position also changes. As a result, the locating plate 8 came into partial contact with the end face of the journal portion 4, making it impossible to secure a proper end plate, and also causing uneven wear of the locating plate.

This idea was made in view of the above-mentioned problems, and the locating plate is fixed to the cylinder block via a spacer that passes through the gasket and the end plate. below,
The camshaft positioning mechanism according to this invention will be explained in detail using the drawings.

FIG. 2 is a sectional view of essential parts showing one embodiment of the camshaft positioning mechanism according to this invention.
The same symbols are used for the same parts as in the figures, and detailed explanation thereof is omitted.

In the figure, reference numeral 13 denotes a pipe-shaped spacer provided between the cylinder block 1 and the locating plate 8, passing through the gasket 5 and the end plate 6.
A bolt 9 passes through the inside. In this case, the length of the spacer 13 is set approximately to the stacked thickness dimension of the gasket 5 and end plate 6 when compressed.

In the camshaft positioning mechanism configured in this way, the gasket 5, end plate 6 and locating plate 8 are connected using bolts 9.
When the laminated body of is fastened together to cylinder block 1,
The locating plate 8 is positioned by the spacer 13, and is securely fixed at a position spaced from the surface of the cylinder block 1 by the length of the spacer 13. Therefore, by defining the length of the spacer 13 in accordance with the axial setting position of the camshaft 3, the camshaft 3 can be reliably positioned. In this case, for long-term use, gasket 5
Although some deformation and distortion occur in the end plate 6, since the positioning of the locating plate 8 with respect to the cylinder block 1 is performed by the spacer 13, such deformation and distortion do not pose a problem and the camshaft 3 Therefore, reliable positioning can be performed at all times.

In addition, in the above embodiment, only the case where a cylindrical body is used as a spacer and a bolt for co-tightening is passed through the inside of the cylindrical body was explained, but this invention is not limited to this, and can be used with a cylinder block. Any structure may be used as long as the gasket and the end plate are inserted between the gasket and the locating plate.

As explained above, in the camshaft positioning mechanism according to this invention, the locating plate is fastened together to the cylinder block via the spacer that passes through the gasket and the end plate. As a result, the deformation and strain of the gasket and end plate will not affect the fixed position and deformation of the locating plate, and as a result, the positioning of the camshaft will be accurate, and at the same time, a regular end plate can be secured. have an effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional camshaft positioning mechanism, and FIG. 2 is a sectional view of a main part of an embodiment of a camshaft positioning mechanism according to this invention. 1... Cylinder block, 3... Camshaft, 4... Journal section, 5... Gasket, 6
... End plate, 8 ... Locating plate, 9 ... Bolt, 10 ... Gear, 12 ... Nut, 13 ... Spacer.

Claims (1)

[Scope of utility model registration request] In a camshaft positioning mechanism that includes a camshaft rotatably supported by a cylinder block of an engine, and a locating plate that is fastened to the cylinder block together with a gasket and an end plate to position the camshaft in the axial direction, the locating plate A camshaft positioning mechanism that includes a spacer for regulating the position of the locating plate that passes through the gasket and end plate between the cylinder block and the cylinder block.