JPH0614006Y2 - Cam case passage joint structure - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a cam case bolted to an upper surface of a cylinder head of an engine having an OHC type valve operating device, and more particularly to a joint structure of a passage portion having an oil passage to a bearing portion of a cam shaft and a cylinder head.

[Prior art]

In an engine having an OHC type valve operating device, a structure is known in which a cam shaft installed above the cylinder head is supported by a cam case separate from the cylinder head. FIG. 3 (a) shows an example thereof. In the engine body, the cylinder head 2 is bolted to the crankcase 1 via a gasket, and the cam case 3 is further bolted to the upper surface of the cylinder head 2. It is three-tiered. Here, the cam case 3 has left and right leg portions 5 and 6 joined to the upper surface of the cylinder head 2 and fixed by bolts 9, and a cam shaft bearing portion 4 arranged between these leg portions 5 and 6. A passage portion 8 having the oil passage 7 to the bearing portion 4 is provided so as to project from the bearing portion 4 toward the upper surface side of the cylinder head 2. And such a cam case 3
Is formed such that the lower end surfaces of the left and right leg portions 5 and 6 and the lower end surface of the passage portion 8 are flush with each other, and when the lower end portion of the passage portion 8 is connected to the upper surface of the cylinder head 2 by the bolt 9. The end surface is in close contact with the upper surface of the cylinder head 2 so that the oil passage 7 in the passage portion 8 communicates with the oil passage 10 on the cylinder head 2 side.

[Problems to be solved by the device]

By the way, in the conventional example configured as described above,
As shown in FIG. 3 (b), when the cylinder head 2 is fastened to the crankcase 1 with the bolts 11, the upper surface of the cylinder head 2 is deformed into a mountain-shaped middle-height shape, or the lower end surface of the passage portion 8 is When protruding from the lower end surfaces of the legs 5 and 6, the legs 5 and 6 of the cam case 3 are connected to the cylinder head 2.
When the bolts 9 are fastened together, the lower end surface of the passage portion 8 directly abuts on the upper surface of the cylinder head 2 and interferes. As a result, the cam case 3 is curved, the hole of the bearing portion 4 is deformed into an elliptical shape, or the axial center of the adjacent bearing portion is displaced, which causes an increase in friction of the cam shaft. And cause damage to the V-belt and timing belt,
This will adversely affect the strength of the camshaft, crankshaft, etc. As measures against such a problem, the rigidity of the bearing portion 4 of the cam case 3 is increased, a rib is added to the cylinder head 2 to prevent the upper surface of the cylinder head 2 from being deformed, and Japanese Utility Model Publication No. 59-35607. As described above, it is conceivable to dispose the passage portion 8 at a location that is not affected when the cam case 3 is bolted. However, in reality, it may not be possible due to space, processing, and structural constraints. The present invention has been made in view of such a point, and it is possible to prevent the deformation of the bearing portion of the cam shaft in the cam case without a large design change and even when the flatness of the upper surface of the cylinder head is poor. It is an object of the present invention to provide a passage connecting structure for a cam case that can be avoided and can surely supply the lubricating oil to the bearing.

[Means for Solving the Problems]

In order to achieve the above object, the present invention is a cam case bolted to the upper surface of a cylinder head, and a passage part for communicating a bearing part of a cam shaft axially supported by the cam case and a lubricating oil passage on the cylinder head side. In the above joint structure, a required recess is formed in the cam shaft bearing portion facing the upper surface of the cylinder head in the cam case, and the cam shaft bearing portion is located in the recess and one end of the cam shaft is A passage structure body that communicates with the inside of the bearing portion and the other end of which opens an oil passage that communicates with the lubricating oil passage on the cylinder head side is projected toward the upper surface of the cylinder head. A ring-shaped seal made of an elastic material having a required facing space between the cylinder head and the upper surface of the cylinder head, which is spaced apart in a non-contact manner so as to be parallel to the head upper surface, and the outer periphery of which is reinforced by a rigid ring. The sealing ring member is compressed between the upper surface of the head and the upper surface of the head as a pressing surface that limits the protruding end of the passage forming body when the cam case is fastened by interposing a sealing member, and is communicated with the sealed oil passage. .

[Action]

According to such a configuration, when the cam case is fastened, the pressing force acting on the bearing portion of the cam shaft between the upper surface of the cylinder head and the upper surface of the cylinder head acts only through the limited pressing surface of the passage forming member, and the seal ring member. Since the pressing force acting on the bearing portion of the cam shaft is reduced in combination with the elastic action of, the deformation of the bearing portion of the cam shaft can be prevented, and the friction resulting from the deformation of the bearing portion can be reduced. Further, since the seal ring member is compressed and hermetically sealed by using the pressing surface having the projecting end surface of the passage structure as a limitation, the structure is not affected by the flatness of the contact surface between the cam case and the cylinder head upper surface. The sealing effect of the oil passage connecting portion can be improved. Further, the projecting dimension of the passage structure provides an effect that the compression rate of the seal ring member can be freely selected as appropriate.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 2 indicates a cylinder head, 3 indicates a cam case, and the cam case 3 includes a cylinder head 2
A required recess is formed in the bearing portion 4 of the cam shaft that faces the upper surface of the cylinder shaft, and is fixed to the upper surface of the cylinder head 2 by the leg portions 5 and 6 for connecting left and right bolts. Then, in the cam case 3, the passage structure 8 having the oil passage 7 to the bearing portion 4 is provided in the same manner as in the case of FIG. 3 described above.
Is formed so as to project toward the upper surface of the. Here, the passage forming body 8 is formed shorter than the leg portions 5 and 6, and the projecting end of the passage forming body 8 is parallel to the upper surface of the head 2 with a required facing interval with respect to the upper surface of the cylinder head 2. So that they are separated in a non-contact manner. A seal ring member 12 is sandwiched between the protruding end surface of the passage forming body 8 and the upper surface of the cylinder head 2 facing the protruding end surface. The seal ring member 12 seals the oil passage 7 in the passage forming body 8. Is communicated with the lubricating oil passage 10 on the cylinder head 2 side. As shown in FIG. 2, the seal ring member 12 has a structure in which a thinner rigid ring 12a is attached to the outer circumference of an elastic ring 12b made of rubber, resin, cork or the like. In one embodiment configured in this way, when the cam case 3 is bolted to the cylinder head 2, the seal ring member 12 is placed on the upper surface of the cylinder head 2 in advance and the circumference of the oil passage 10 opened there. Set to surround. Then, the leg portions 5 and 6 of the cam case 3 are joined to the upper surface of the cylinder head 2 by bolts 9 with the protruding end surface of the passage forming body 8 of the cam case 3 being joined to the seal ring member 12. Then, the seal ring member 12 has the elastic ring 12
b is compression-deformed with the upper surface of the cylinder head 2 as a pressing surface that limits the protruding end surface of the passage forming body 8 of the cam case 3, and thus the oil passage 7 in the passage forming body 8 is compressed.
And the lubricating oil passage 10 on the cylinder head 2 side communicate with each other. Since the elastic ring 12b has the rigid ring 12a mounted on the outer periphery thereof, it retains a circular regular ring shape along the rigid ring 12a even when it is compressed and deformed, and a high hydraulic pressure acts on the inside. Even elastic ring 12b
Does not inadvertently swell to the outer peripheral side and cause a defective seal. Therefore, a reliable seal is provided between the protruding end surface of the passage structure 8 and the upper surface of the cylinder head 2. Further, as described above, in the state where the cam case 3 is bolted to the cylinder head 2, the seal ring member 12 is formed between the upper surface of the cylinder head 2 and the upper surface of the cylinder head 2 as a pressing surface limited by the protruding end surface of the passage forming body 8 of the cam case 3. Because of the compressive deformation, the bearing portion 4 of the cam case 3 is prevented from being deformed without exerting an unreasonable pressing force.

[Effect of device]

As described above, according to the configuration of the present invention, the pressing force acting on the bearing portion 4 of the cam shaft between the upper surface of the cylinder head 2 and the upper surface of the cylinder head 2 when the cam case 3 is fastened is generated only through the projecting end surface of the passage forming body 8. In combination with the elastic action of the seal ring member 12, the pressing force acting on the bearing portion 4 of the cam shaft is reduced, so that the deformation of the bearing portion 4 of the cam shaft can be prevented,
Friction due to deformation of the bearing portion 4 can be reduced. Further, since the seal ring member 12 is configured to be compressed and sealed by using the pressing surface of the passage forming body 8 that limits the protruding end surface,
The structure is not affected by the flatness of the contact surface between the cam case 3 and the upper surface of the cylinder head 2, and the sealing effect of the oil passage connecting portion can be improved. Further, depending on the projecting size of the passage structure 8, the compression ratio of the seal ring member 12 can be appropriately selected as desired, and so on.

[Brief description of drawings]

FIG. 1 is a side view showing a partial cross section of an embodiment of the present invention, FIG. 2 is a cross sectional view of a seal ring member in one embodiment, and FIGS. 3 (a) and 3 (b) are conventional examples. It is a side view shown as a partial cross section. 2 ... Cylinder head, 3 ... Cam case, 4 ... Bearing part, 5, 6 ... Leg part, 7 ... Oil passage, 8 ... Passage structure, 9 ... Bolt, 10 ... Lubricating oil passage, 12 …… Seal ring member.

Claims (1)

[Scope of utility model registration request] 1. A joint structure of a cam case bolted to an upper surface of a cylinder head, wherein a bearing portion of a cam shaft axially supported by the cam case and a passage portion for communicating a lubricating oil passage on the cylinder head side are connected to each other. In the cam case, a required recess is formed in the bearing portion of the cam shaft facing the upper surface of the cylinder head, the recess is located in the recess, and the bearing portion of the cam shaft communicates with one end of the bearing portion of the cam shaft. A passage structure having an oil passage, the other end of which communicates with a lubricating oil passage on the cylinder head side, is projected toward the upper surface of the cylinder head, and the projecting end of the passage structure is opposed to the upper surface of the cylinder head. And a non-contact space that is parallel to the upper surface of the head with a required facing space, and an annular seal ring member made of an elastic material whose outer periphery is reinforced with a rigid ring is interposed in the space. When the cam case is fastened, the seal ring member is compressed as a pressing surface with the projecting end of the passage structure limited to the upper surface of the cylinder head and communicates with the sealed oil passage. .