JPS632682Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a support structure for a chain guide of an engine, and in particular to a chain guide that slides into contact with the tension side of the chain that takes out the rotation of the crankshaft to prevent waving. Regarding support structures.

[Prior Art]

In an engine, the rotation of the crankshaft is transmitted to the driven shaft to drive the camshaft for the intake and exhaust valves or the oil pump for lubrication connected to the driven shaft. In this case, the rotation transmission means is a chain. A sprocket mechanism may be used.

In this type of chain sprocket mechanism, on the tension side of the chain, that is, on the side running from the driven shaft to the crankshaft (drive shaft),
A guide member, ie, a chain guide, made of a rubber-like elastic body is brought into contact with the chain guide under a predetermined pressure, thereby preventing the chain from waving and thereby preventing noise.

Conventionally, structures for supporting this type of chain guide include a structure in which the chain guide is screwed to the crankcase or to the crankcase and other appropriate locations (for example, a cylinder head), or a structure in which the chain guide is made of rubber-like elastic material. A structure has been adopted in which a locking portion is provided and the locking portion is pressed into and fixed into a fitting portion formed on a crankcase or the like.

However, such a conventional structure has problems in that it is complex, requires a large number of processing steps, and requires time and effort to attach the chain guide.

[Purpose of invention]

The purpose of the present invention is to solve the problems of the prior art as described above, and to provide a chain guide support structure for an engine that has a simple structure, reduces the number of processing steps, and allows the chain guide to be installed extremely easily. .

[Structure of the idea]

The present invention provides a novel structure in which the chain guide can be positioned and supported simply by inserting protrusions provided on both sides of the chain guide into grooves formed in the crankcase.

That is, according to the present invention, in the support structure of the chain guide that slides in contact with the tension side of the chain that transmits the rotation of the crankshaft to the driven shaft, protrusions are provided on both sides of the chain guide closer to the crankshaft, and There is provided a chain guide support structure for an engine, characterized in that grooves are formed on both sides of the chain, and the crankshaft side is closed and the other end is open, and the protrusions are inserted into the grooves for positioning and support.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an engine chain guide support structure according to an embodiment of the present invention.

In FIG. 1, a cylinder 2 is connected to the upper surface of a crankcase 1, a cylinder head 3 is connected to the upper surface of the cylinder 2, and a head cover 4 is connected to the upper surface of the cylinder head 3.

The illustrated crankcase 1 is constructed by joining an upper case half 1A and a lower case half 1B, and a crankshaft 5 is supported on the crankcase 1.

Between the cylinder head 3 and head cover 4 is a rocker arm chamber 6 that houses the intake and exhaust valve drive mechanism.
is formed, and two camshafts 7, 8 are supported within the rocker arm chamber 6. These camshafts 7 and 8 drive intake and exhaust valves (not shown), so the illustrated engine is a double overhead camshaft type (DOHC) equipped with two camshafts 7 and 8. be.

As is well known, an engine is constructed by assembling various mechanisms such as connecting rods, pistons, intake and exhaust valves, but in this case, only the parts related to the present invention and its embodiments will be shown, and other mechanisms will not be explained. Omitted.

The crankshaft 5 is provided with a sprocket gear 9, and the camshafts 7, 8 are provided with sprocket gears 10, 11, and an endless chain 12 is wound around these sprockets 9, 10, 11. There is. This endless chain 12 is usually called a cam chain, and the camshaft 7,
8 rotates in synchronization with the crankshaft 5, and the intake and exhaust valves are opened and closed at predetermined crank angle timing by the camshafts 7 and 8.

The tension side of the cam chain 12, that is, the portion running from the camshaft 7, which is a driven shaft, to the crankshaft 5, which is a driving shaft, is guided in sliding contact with a chain guide 13 supported inside the engine.

On the other hand, a chain tensioner 14 is installed on the slack side of the cam chain 12, that is, the side that runs from the crankshaft 5 to the camshaft (driven shaft) 8.
is provided. This chain tensioner 1
4 is installed so as to always press against the cam chain 12 with a predetermined pressure by a contact pressure maintaining means 15 that operates in the projecting direction.

The chain guide 13 and chain tensioner 14 are used to prevent the chain from waving and to prevent noise generation.

2 to 4 show the chain guide 13. FIG.

The chain guide 13 has a structure in which a shoe 17 made of a rubber-like elastic material is joined to a base plate 16 made of a rigid material such as a steel plate, and is assembled so that the shoe 17 is in sliding contact with the cam chain 12 as shown in FIG.

However, protrusions 18, 18 are formed on both sides of the chain guide 13 at a position closer to the crankshaft (see FIGS. 1 and 2). In the illustrated example, these protrusions 18, 18 are formed by covering both side protrusions of the base plate 16 with a rubber-like elastic material.

Also, the back side of the base plate 16 (show 17)
On the opposite side), a support portion 19 is provided at a position closer to the driven shaft (camshaft 7), and a steady rest 20 is provided at an intermediate position. These support parts 19
The steady rest 20 is formed by joining a rubber-like elastic body to the base plate 16, and in the assembled state shown in FIG. and facing the wall surface of the cylinder 2.

FIG. 5 shows a top view of the crankcase 1 seen from the mating surface with the cylinder 2, and FIG. 6 shows a longitudinal cross-section of the central part of the crankcase 1.

As shown in Fig. 5, there are two cylinders 2 (Fig. 1) connected to the upper surface of the crankcase 1, and a chain/sprocket mechanism consisting of a cam chain 12 (Fig. 1) is housed between these cylinders. A cavity 21 is formed for this purpose.

On both sides of the cavity 21, a pair of grooves 22, 22 are formed at both sides of the tension side of the cam chain 12. These grooves 22 are provided so as to position and support the chain guide 13 at a predetermined position by inserting the protrusions 18, 18 on both sides of the chain guide 13. That is,
Each groove 22, 22 has a shape in which the crankshaft 5 side is closed (dead end) and the other end is open. By inserting (dropping) the chain guide 13 from the open end side, the protrusions 18, 18 are supported at the closed ends (inner dead ends) of the grooves 22, 22, and the chain guide 13 is positioned and supported in the state shown in FIG.

Therefore, the assembly of the chain guide 13 can be accomplished by simply inserting or dropping the chain guide 13 into the grooves 22, 22 of the crankcase 1. Even after the cylinder 2 and cylinder head 3 have been assembled, the cylinder head 3 can be inserted from above before the chain 12 is installed.

According to the embodiment described above, the following effects can be obtained.

(i) No bolting or pressing work is required;
The chain guide 13 can be assembled by simply inserting it, so that an engine chain guide support structure with excellent assembly workability can be obtained.

(ii) The chain guide insertion grooves 22, 22 can be formed synchronously with the crankcase 1, so special machining such as bolt hole machining can be omitted, and the number of machining steps can be reduced. .

(iii) Furthermore, since the structure is simple and there are no fastening or press-fitting points, maintenance and inspection as well as disassembly work at that time can be carried out extremely easily.

In the illustrated embodiment, two driven shafts (camshafts) 7 and 8 are provided, but the present invention can be similarly applied to a case where there is one driven shaft or three or more driven shafts.

Further, in the above embodiment, the present invention is applied to the cam chain 12 of an engine, but the present invention can be applied to any device that is driven by a chain by the crankshaft 5. The present invention can be similarly applied to, for example, chain-driving an oil pump or the like.

[Effect of idea]

As is clear from the above description, the present invention provides an engine chain guide support structure that is easy to assemble and disassemble and can reduce manufacturing man-hours.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the main parts of an engine equipped with a chain guide support structure according to an embodiment of the present invention, FIG. 2 is a side view of the chain guide shown in FIG. 1,
Figure 3 is a back view of Figure 2, Figure 4 is a sectional view taken along the line - in Figure 2, Figure 5 is a top view of the crankcase in Figure 1, and Figure 6 is in Figure 5. line -
It is a partially sectional elevational view seen from. 1... Crank case, 5... Crankshaft, 7, 8... Driven shaft (camshaft), 9, 1
0, 11...Sprocket, 12...Chain (cam chain), 13...Chain guide, 1
8, 18...Protrusion (chain guide), 22, 2
2...Groove.

Claims (1)

[Scope of utility model registration request] In a support structure for a chain guide that slides into contact with the tension side of the chain that transmits the rotation of the crankshaft to the driven shaft, protrusions are provided on both sides of the chain guide closer to the crankshaft, and protrusions are provided on both sides of the chain in the crankcase. Forming a groove that is closed and open at the other end,
A chain guide support structure for an engine, characterized in that the protrusion is inserted into the groove for positioning and support.