Patent Description:
The tensioner lever described in <CIT> has a conventionally known configuration for efficient use of lubricating oil in a chain guide assembly used, for instance, in a timing system of an engine.

The pivoting chain guide (tensioner lever <NUM>) described in <CIT> is attached to an inner wall E of an engine via a pivot shaft (shoulder bolt SB) passed through an axial support boss <NUM>. An oil guide groove <NUM> is formed by cutting off an outer peripheral portion of the axial support boss <NUM> radially inward to guide oil (engine oil O) that gathered and adhered on the lever body <NUM> toward a bolt passage area <NUM> of the axial support boss <NUM>.

Thus, when the lever is attached to the inner wall E of the engine, with the lengthwise distal end of the lever being oriented upward and the axial support boss <NUM> at the lengthwise base end of the lever being oriented downward, the oil (engine oil O) that gathered and adhered on the inner wall E of the engine flows down along both front and back sides of the lever body <NUM> and infiltrates the entire bolt passage area <NUM> of the axial support boss <NUM>, regardless of whether the axial support boss <NUM> is making tight contact with the inner wall E of the engine or with a flange Sf of the pivot shaft (shoulder bolt SB). This way, the oil (engine oil O) on the inner wall E of the engine can be maximally utilized as lubricating oil in an efficient manner to suppress galling, seizure, uneven wear, and friction loss that the pivot shaft (shoulder bolt SB) tends to suffer and favorable durability can be ensured. Smooth pivoting motion of the chain guide to follow the movement of the drive chain C can be also ensured, giving a correct tension to the chain in concert with a tensioner T.

An oil communication passage <NUM> integrally formed to the lever body <NUM> at the foot of inclined reinforcing ribs <NUM> also ensures smooth continuous flow of the oil (engine oil O) that gathered and adhered on the entire lever body <NUM> from the distal end to the base end without being stopped by the reinforcing ribs <NUM>. This way, the excess oil (engine oil O) gathering and adhering on the entire lever body <NUM> can be supplied into the oil guide groove <NUM> at the base end efficiently.

<CIT> discloses: A detachable timing gear cassette unit for an internal combustion engine. The cassette has side walls separate from the cylinder block of the engine, and the side walls form a housing. The housing contains the camshaft sprocket, the crankshaft sprocket, a timing chain that connects the sprockets, a tensioner to maintain a suitable tension in the timing chain and positioning ribs to position the sprockets within the housing. Engine oil is circulated through the housing, in a generally downwardly direction, to lubricate the sprockets and the chain and to cool the oil. The cooling of the oil is assisted by internal ribs on the inside of the housing and by external ribs on the outside of the housing.

Further relevant background art for the present invention is described in <CIT>.

The configuration for efficient use of lubricating oil in the pivoting chain guide described in <CIT> still has some scope of improvement.

Namely, the pivoting chain guide described in <CIT> is designed to suppress galling, seizure, uneven wear, and friction loss of the pivot shaft by collecting and guiding the oil that adhered to the lever body toward the pivot shaft. On the other hand, oil that adhered to other parts of the chain guide assembly than the pivoting chain guide is not collected or guided. Efficient use of the oil for other parts than the pivoting chain guide is not possible when, for example, the chain, or a fixed chain guide that slidably guides the chain, or a drive sprocket the chain is passed around, are not supplied with sufficient oil. As a result, the overall amount of use of the oil has to be increased.

The present invention solves these problems, and aims at providing a chain guide assembly frame capable of efficiently collecting the oil that adhered to various parts of the chain guide assembly, and guiding the collected oil to predetermined locations, to allow efficient use of oil, with a simple structure.

The present invention solves the above problems by providing a chain guide assembly frame including a main body and a driven sprocket holding portion that clamps a driven sprocket in an upper part of the main body, the main body including a fixed chain guide, and a pivoting chain guide holding portion to which a pivoting chain guide is mountable. The driven sprocket holding portion includes a fixed-guide-side sprocket holding portion provided on a fixed chain guide side, and a pivoting-guide-side sprocket holding portion provided on a pivoting chain guide holding portion side. The main body includes a drive sprocket holding portion holding a drive sprocket and located lower than the driven sprocket holding portion. The main body includes a concave and/or convex oil passage extending from an upper part toward a lower part to guide oil toward above the drive sprocket holding portion.

The chain guide assembly frame according to claim <NUM> includes a concave and/or convex oil passage in the main body, extending from an upper part downward to guide oil toward an area above the drive sprocket holding portion. The oil that adhered in the upper part of the main body is thus collected into the oil passage, and reliably guided toward the drive sprocket holding portion in the lower part of the main body. Therefore, the drive sprocket can be lubricated sufficiently with a reduced amount of oil compared to the case where no oil passage is provided.

According to the configuration set forth in claim <NUM>, the oil passage, at a lower end thereof on a drive sprocket holding portion side, diverges into a fixed-guide-side oil passage formed extending toward the fixed chain guide and a pivoting-guide-side oil passage formed extending toward the pivoting chain guide holding portion. The oil that adhered in the upper part of the main body can be guided not only to the drive sprocket but also to the fixed chain guide that makes sliding contact with the chain, and the pivoting chain guide holding portion. Various parts can be supplied with oil in a more efficient manner in this way and sufficiently lubricated with a reduced amount of oil compared to the case where no oil passage is provided.

According to the configuration set forth in claim <NUM>, the main body includes a top guide. The oil passage includes an upper oil passage formed extending from the top guide through between the fixed-guide-side sprocket holding portion and the pivoting-guide-side sprocket holding portion, and a lower oil passage formed at a position lower than the upper oil passage. The oil that adhered around the top guide can be reliably collected into the upper oil passage, and guided to between the fixed-guide-side sprocket holding portion and the pivoting-guide-side sprocket holding portion. The oil guided from the upper oil passage is then guided to various parts from the lower oil passage. Various parts can thus be supplied with oil in a more efficient manner.

According to the configuration set forth in claim <NUM>, the upper oil passage has a lower end formed to be positioned directly above a topmost part of the lower oil passage. The lower oil passage may diverge midway, but the oil is guided directly from the upper oil passage to the lower oil passage before the diverging point, so that a sufficient amount of oil can be reliably guided from the upper oil passage to both destinations of the diverged lower oil passage.

According to the configuration set forth in claim <NUM>, the upper oil passage diverges to have a lower end formed to be positioned directly above the fixed-guide-side lower oil passage and a lower end formed to be positioned directly above the pivoting-guide-side lower oil passage. Therefore, the oil can be guided reliably and sufficiently from the upper oil passage to both of the fixed-guide-side lower oil passage and pivoting-guide-side lower oil passage.

According to the configuration set forth in claim <NUM>, the upper oil passage includes a fixed-guide-side upper oil passage formed on a fixed-guide-side sprocket holding portion side, and a pivoting-guide-side upper oil passage formed on a pivoting-guide-side sprocket holding portion side. In the case where the top guide stretches over a wide area as far as above the fixed-guide-side sprocket holding portion and pivoting-guide-side sprocket holding portion, a substantial amount of oil that adhered to a wide area of the top guide can be collected, so that more oil can be guided to various parts through the oil passage.

According to the configuration set forth in claim <NUM>, the fixed-guide-side upper oil passage has a lower end formed to be positioned directly above the fixed-guide-side lower oil passage, and the pivoting-guide-side upper oil passage has a lower end formed to be positioned directly above the pivoting-guide-side lower oil passage. The amount of oil collected from near the top guide by each of the fixed-guide-side upper oil passage and pivoting-guide-side upper oil passage can be adjusted by varying the positions or shapes of their upper ends. The ratio of oil to be supplied to the fixed-guide-side lower oil passage and pivoting-guide-side lower oil passage can thus be adjusted to guide an adequate amount of oil to various parts for even more suitable lubrication.

According to the configuration set forth in claim <NUM>, the pivoting-guide-side oil passage has a lower end formed to be positioned directly above the drive sprocket holding portion. Therefore, oil can be guided reliably from the upper part of the main body to the drive sprocket holding portion.

According to the configuration set forth in claim <NUM>, the oil passage is formed in a weld bead shape. Therefore, the oil passage, which may be either concave or convex, can be formed on both front and back sides of the main body by a single machining process.

Moreover, the oil passage formed as a weld bead on the surface of the main body can increase the strength of the main body itself.

A chain guide assembly frame <NUM> according to one embodiment of the present invention will be hereinafter described with reference to the drawings.

For ease of explanation, <FIG> does not illustrate the engine, or connection members that connect the engine and the frame <NUM>.

As shown in <FIG>, the chain guide assembly frame <NUM> includes a main body <NUM>, a top guide <NUM> provided on the upper surface of the main body <NUM>, a fixed chain guide <NUM> provided on one side face of the main body <NUM>, and a pivoting chain guide holding portion <NUM> to which a pivoting chain guide <NUM> can be attached on a side face of the main body <NUM> opposite from the fixed chain guide <NUM>. A fixed-guide-side sprocket holding portion <NUM> is provided in an upper part of the main body <NUM> on the same side as the fixed chain guide <NUM>, and a pivoting-guide-side sprocket holding portion <NUM> is provided in an upper part of the main body <NUM> on the same side as the pivoting chain guide holding portion <NUM>. A drive sprocket holding portion <NUM> that can hold a drive sprocket DS is provided in a lower part of the main body <NUM>.

Mounting holes H1, H2, H3 used when fixing the frame to an engine (not shown) are provided in various parts of the main body <NUM>.

An oil passage including a fixed-guide-side upper oil passage <NUM> and a pivoting-guide-side upper oil passage <NUM> is formed in a vertically extending weld bead shape, i.e., convex on one side of the main body <NUM> and concave on the other side, each extending from near the top guide <NUM> between the fixed-guide-side sprocket holding portion <NUM> and the pivoting-guide-side sprocket holding portion <NUM> as far as to near the mounting hole H2.

Below the mounting hole H2 are provided a fixed-guide-side lower oil passage <NUM> that is an oil passage extending from near the mounting hole H2 gradually downward and toward the fixed chain guide <NUM>, and a pivoting-guide-side lower oil passage <NUM> that is an oil passage extending from near the mounting hole H2 gradually downward as far as to near the drive sprocket holding portion <NUM>, passing on the side of the pivoting chain guide holding portion <NUM> of the main body <NUM>. The fixed-guide-side lower oil passage <NUM> and pivoting-guide-side lower oil passage <NUM> are connected at their tops near the mounting hole H2.

An auxiliary oil passage <NUM> that is an oil passage running parallel to a lower part of the pivoting-guide-side lower oil passage <NUM> is formed below the mounting hole H3.

The fixed-guide-side lower oil passage <NUM>, pivoting-guide-side lower oil passage <NUM>, and auxiliary oil passage <NUM> are formed as weld beads similarly to the fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM>.

Since the fixed-guide-side upper oil passage <NUM>, pivoting-guide-side upper oil passage <NUM>, fixed-guide-side lower oil passage <NUM>, pivoting-guide-side lower oil passage <NUM> and auxiliary oil passage <NUM> are formed as weld beads as described above, they can help minimize deflection of the main body <NUM> and increase the strength.

Next, how oil EL is guided in the chain guide assembly frame <NUM> according to one embodiment of the present invention will be described with reference to <FIG>.

As shown in <FIG>, the chain guide assembly frame <NUM> holds a driven sprocket S1 in the fixed-guide-side sprocket holding portion <NUM>, holds a driven sprocket S2 in the pivoting-guide-side sprocket holding portion <NUM>, and holds a drive sprocket DS in the drive sprocket holding portion <NUM>. A chain CH is passed around the driven sprockets S1 and S2, and drive sprocket DS.

The pivoting chain guide <NUM> is pivotably connected to the pivoting chain guide holding portion <NUM> via a pivot shaft <NUM>, to press the chain CH and create a predetermined tension in the chain CH.

The chain CH is passed around such as to make sliding contact with the fixed chain guide <NUM>, pivoting chain guide <NUM>, and top guide <NUM>.

The chain guide assembly frame <NUM> is attached to the engine (not shown) via the mounting holes H1, H2, and H3 in this state.

Oil EL is supplied to the chain guide assembly attached to the engine (not shown) for lubricating the chain CH and various parts of the chain guide assembly. Some of the oil EL, squirted when supplied to the chain guide assembly, or scattered by spinning driven sprockets S1 and S2 or drive sprocket DS, or splashing from the running chain CH in sliding contact with the fixed chain guide <NUM>, pivoting chain guide <NUM>, and top guide <NUM>, directly adheres to the main body <NUM>. Some of the oil EL in mist form floating around the frame <NUM> of the chain guide assembly also adheres to the main body <NUM>.

While it depends on from where the oil EL is supplied, the oil EL generally adheres more in upper parts of the main body <NUM> and flows down slowly along the main body <NUM>.

Since the fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM> are provided in upper parts of the main body <NUM>, the oil EL <NUM> that adhered around the fixed-guide-side sprocket holding portion <NUM> near the top guide <NUM> is collected in the fixed-guide-side upper oil passage <NUM>. The oil EL <NUM> that adhered around the pivoting-guide-side sprocket holding portion <NUM> near the top guide <NUM> is collected in the pivoting-guide-side upper oil passage <NUM>. The oil EL <NUM> and EL <NUM>, after traveling along the respective weld bead shapes of the fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM> and reaching the lower ends, flows down from the respective oil passages.

The fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM> have their respective upper ends positioned closer to the fixed-guide-side sprocket holding portion <NUM> and pivoting-guide-side sprocket holding portion <NUM>, and lower ends positioned closer to the center of the main body <NUM>. Therefore, oil EL <NUM> and EL <NUM> that adhered to the main body <NUM> above the fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM> can be efficiently collected from a wide area.

The oil EL <NUM> and EL <NUM> that flowed down from the respective lower ends of the fixed-guide-side upper oil passage <NUM> and pivoting-guide-side upper oil passage <NUM> is collected respectively in the fixed-guide-side lower oil passage <NUM> and pivoting-guide-side lower oil passage <NUM>, and flows down from the lower ends along the weld bead shapes of the fixed-guide-side lower oil passage <NUM> and pivoting-guide-side lower oil passage <NUM>.

Since the lower end of the fixed-guide-side lower oil passage <NUM> is positioned above the fixed chain guide <NUM>, the oil EL <NUM> collected from around the top guide <NUM> is supplied to the fixed chain guide <NUM>, whereby the slidability of the chain CH on the fixed chain guide <NUM> can be more improved.

Since the lower end of the pivoting-guide-side lower oil passage <NUM> is positioned directly above the drive sprocket holding portion <NUM>, the oil EL <NUM> collected from around the top guide <NUM> is supplied to the drive sprocket DS. The drive sprocket DS can thus be lubricated in an efficient manner, and the oil EL <NUM> can be further supplied to the chain CH via the drive sprocket DS.

The pivoting-guide-side lower oil passage <NUM> extends along the main body <NUM> on the side of the pivoting chain guide holding portion <NUM> down to directly above the drive sprocket holding portion <NUM> and is not configured to collect oil EL <NUM> that adhered above the mounting hole H3 of the main body <NUM>. However, the auxiliary oil passage <NUM> is formed below the mounting hole H3 so that the oil EL <NUM> is collected in the auxiliary oil passage <NUM>.

Since the lower end of the auxiliary oil passage <NUM> is positioned directly above the drive sprocket holding portion <NUM>, the oil EL <NUM> is also supplied to the drive sprocket DS. The drive sprocket DS can thus be lubricated more efficiently.

The oil EL that adhered to the main body <NUM> is collected in this way by the fixed-guide-side upper oil passage <NUM>, pivoting-guide-side upper oil passage <NUM>, fixed-guide-side lower oil passage <NUM>, pivoting-guide-side lower oil passage <NUM>, and auxiliary oil passage <NUM>, and guided to predetermined locations. Therefore, various parts such as the chain CH and drive sprocket DS can be efficiently lubricated using a reduced amount of oil EL as compared to the case in which no oil passages are provided.

While one embodiment of the present invention has been described in detail, the present invention is not limited to the embodiment described above and may be carried out with various design changes without departing from the scope of the present invention set forth in the claims.

In the above-described embodiment, a fixed-guide-side upper oil passage and a pivoting-guide-side upper oil passage are formed in an upper part of the main body. The configuration of the oil passages to be provided in an upper part of the main body is not limited to this example. A fixed-guide-side upper oil passage and a pivoting-guide-side upper oil passage may be formed such as to merge on their way down, for example. One oil passage extending from an upper part of the main body may split into a fixed-guide-side upper oil passage and a pivoting-guide-side upper oil passage somewhere along the way down. Alternatively, the main body may be formed with only one oil passage.

In the above-described embodiment, a fixed-guide-side lower oil passage and a pivoting-guide-side lower oil passage are formed below the fixed-guide-side upper oil passage and pivoting-guide-side upper oil passage, and the upper ends of the fixed-guide-side lower oil passage and pivoting-guide-side lower oil passage are joined together. The configurations of the fixed-guide-side lower oil passage and pivoting-guide-side lower oil passage are not limited to this example. The fixed-guide-side lower oil passage and pivoting-guide-side lower oil passage may not be joined together, for example. There may be no fixed-guide-side lower oil passage or pivoting-guide-side lower oil passage. Alternatively, the lower end of the fixed-guide-side upper oil passage may be connected to the upper end of the fixed-guide-side lower oil passage.

In the above-described embodiment, the lower end of the fixed-guide-side lower oil passage is positioned above the fixed chain guide. The fixed-guide-side lower oil passage may have its lower end positioned anywhere, below the fixed chain guide for example, or directly above the mounting hole H3.

In the above-described embodiment, the lower end of the pivoting-guide-side lower oil passage is positioned directly above the drive sprocket holding portion. The pivoting-guide-side lower oil passage may have its lower end positioned anywhere, directly above the pivoting chain guide holding portion for example, or, the pivoting-guide-side lower oil passage may diverge somewhere to have lower ends, one directly above the pivoting chain guide holding portion and the other directly above the drive sprocket holding portion.

While an auxiliary oil passage is formed below the mounting hole H3 in the above-described embodiment, the configuration of the auxiliary oil passage is not limited to this example. There may be no auxiliary oil passage for example, or an auxiliary oil passage may be formed above the mounting hole H3 such that its lower end merges with the pivoting-guide-side lower oil passage.

While a top guide is provided at the top of the main body in the above-described embodiment, the frame configuration of the chain guide assembly is not limited to this example. The top guide may be omitted, for example.

Claim 1:
A chain guide assembly frame (<NUM>) comprising a main body (<NUM>) and a driven sprocket holding portion that is able to clamps a driven sprocket in an upper part of the main body (<NUM>),
the main body (<NUM>) including a fixed chain guide (<NUM>), and a pivoting chain guide holding portion (<NUM>) to which a pivoting chain guide (<NUM>) is mountable, the driven sprocket holding portion including a fixed-guide-side sprocket holding portion (<NUM>) provided on a fixed chain guide (<NUM>) side, and a pivoting-guide-side sprocket holding portion (<NUM>) provided on a pivoting chain guide (<NUM>) holding portion side, the main body (<NUM>) including a drive sprocket holding portion (<NUM>) that is able to hold a drive sprocket and located lower than the driven sprocket holding portion, the main body (<NUM>) including a concave and/or convex oil passage extending from an upper part toward a lower part to guide oil toward above the drive sprocket holding portion (<NUM>),
the main body (<NUM>) includes, in an upper part thereof, a top guide (<NUM>) and the oil passage includes an upper oil passage formed extending from the top guide (<NUM>) through between the fixed-guide-side sprocket holding portion (<NUM>) and the pivoting-guide-side sprocket holding portion (<NUM>), and a lower oil passage formed at a position lower than the upper oil passage,
characterized in that
the upper oil passage includes a fixed-guide-side upper oil passage (<NUM>) formed on a fixed-guide-side sprocket holding portion (<NUM>) side, and a pivoting-guide-side upper oil passage (<NUM>) formed on a pivoting-guide-side sprocket holding portion (<NUM>) side.