Chain guide mechanism frame

Abstract

To provide a frame of a chain guide mechanism which can, with a simple constitution, surely maintain a proper positional relationship between a driven sprocket and a sprocket holding part without causing a fall of the driven sprocket even when sufficient tension is not applied to a chain.SOLUTION: In a frame 100 of a chain guide mechanism, a main body part 110 has a fixed-side sprocket holding part 120 and an oscillation-side sprocket holding part 130. The fixed-side sprocket holding part 120 has a fixed-side first support part 121 for supporting a driven sprocket S1 at a first contact point 121a, and a fixed-side second support part 122 for supporting the driven sprocket at a second contact point 122a on an outer side of the first contact point 121a. When supporting the driven sprocket S1 at the first contact point 121a and the second contact point 122a, and bringing them into a forward-erected state, a vector of gravity SG applied on a center of gravity SC of the driven sprocket S1 is oriented toward between the first contact point 121a and the second contact point 122a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a frame for a chain guide mechanism used in an engine timing system or the like. [Background technology]

[0002] BACKGROUND ART Conventionally, a timing chain mechanism such as that disclosed in Patent Document 1 is known as a chain guide mechanism used in engine timing systems and the like.

[0003] The frame of the chain guide mechanism (timing chain mechanism) described in Patent Document 1 has a main body (chain damper 13) and a sprocket holding part that holds a driven sprocket (cam sprockets 10a, 10b) on the top of the main body (chain damper 13), and in a pre-assembled state, the driven sprockets (cam sprockets 10a, 10b) are placed in the sprocket holding part and the driving sprocket (crank sprocket 12) is placed in the driving sprocket holding part, and a chain (timing chain 11) is then wound around it. In addition, a fixed chain guide (guide portion 13a) that guides the tension side of the chain (timing chain 11) is provided on the tension side of the chain (timing chain 11) of the main body portion (chain damper 13), and a swingable chain guide (chain slipper 14) that has a fixed swing shaft (swing fulcrum portion) and is swingable, guides the chain (timing chain 11), and has a tension applying function is provided on the slack side of the chain (timing chain 11). In addition, the main body (chain damper 13) is pivotally supported on the swing axis (swing fulcrum) of the oscillating chain guide (chain slipper 14) so ​​that it can swing, and the main body (chain damper 13) is provided with a support portion 13d that can support the driven sprocket (cam sprockets 10a, 10b) by swinging the main body (chain damper 13) counterclockwise around the swing axis (swing fulcrum), and a regulating portion 13b that can regulate the swing of the chain (timing chain 11) of the oscillating chain guide (chain slipper 14) toward the slack side.

[0004] In addition, a chain stopper guide 16 is pivotally supported on the swing axis (swing fulcrum) of the swing chain guide (chain slipper 14) so ​​that it can swing. The chain stopper guide 16 is provided with a support portion 16c that can support the drive sprocket (crank sprocket 12) by swinging clockwise around the swing axis (swing fulcrum), and is also provided with a locking portion 16a. The locking portion 16a of this chain stopper guide 16 and the locking portion 13c of the main body (chain damper 13) are connected by a spring 17, and the chain stopper guide 16 is biased clockwise around the swing axis (swing fulcrum portion), while the main body (chain damper 13) is biased counterclockwise around the swing axis (swing fulcrum portion). As a result, the driven sprockets (cam sprockets 10a, 10b) are pressed by the chain (timing chain 11) and are clamped between the support portion 13d, and the drive sprocket (crank sprocket 12) is also pressed by the chain (timing chain 11) and is clamped between the support portion 16c, so that the drive sprocket (crank sprocket 12) and the driven sprockets (cam sprockets 10a, 10b) can be maintained in a provisionally assembled state without shifting their positions before assembly into the internal combustion engine. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-63128 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the frame of the chain guide mechanism of Patent Document 1 still has room for improvement. In other words, the frame of the chain guide mechanism described in Patent Document 1 is provided with a chain stopper guide that is a separate component from the main body, and the main body and chain stopper guide are connected by a spring, which increases the number of parts and could lead to increased costs. Therefore, a known frame for a chain guide mechanism has a sprocket holder and a drive sprocket holder on the main body without a chain stopper guide, and the swinging chain guide is connected to the swinging chain guide holder on the main body.

[0007] However, before the chain is biased by the swinging chain guide, insufficient tension is applied to the driven sprocket due to the weight of the chain during the pre-assembly process, which could cause the driven sprocket to fall off the sprocket holder. Furthermore, even if a jig or the like is used to apply sufficient tension to the chain when transporting it before attaching it to an engine, etc., there is a risk that the jig may come off due to vibration, etc., resulting in insufficient tension on the chain and causing the sprocket to fall off the sprocket holding portion.

[0008] The present invention aims to solve these problems by providing a frame for a chain guide mechanism that has a simple structure and that can reliably maintain the correct positional relationship between the driven sprocket and the sprocket holding part, without causing the driven sprocket to fall off even when there is insufficient tension in the chain or when the tension applied to the chain is suddenly released. [Means for solving the problem]

[0009] The frame of the chain guide mechanism of the present invention is a frame for a chain guide mechanism having a main body and a sprocket holding part that supports a driven sprocket, and the main body has a swinging chain guide holding part to which a swinging chain guide can be attached, and a fixed chain guide, and the sprocket holding part has a fixed-side sprocket holding part provided on the fixed chain guide side and a swinging-side sprocket holding part provided on the swinging chain guide holding part side, and the fixed-side sprocket holding part has at least a fixed-side first support part that supports the driven sprocket placed on the fixed-side sprocket holding part from below at a first contact point, and a fixed-side second support part that supports the driven sprocket at a second contact point located outside the first contact point, and when the driven sprocket is supported by the fixed-side first support part and the fixed-side second support part simultaneously and in an upright state, the vector of gravity acting on the center of gravity of the driven sprocket is oriented between the first contact point and the second contact point The fixed-side first support portion is formed so as to be farther away from the center of gravity of the driven sprocket in a state where it is supported by the fixed-side first support portion and the fixed-side second support portion as it approaches the fixed-side second support portion. This solves the above problem. [Effects of the Invention]

[0010] The frame of the chain guide mechanism according to claim 1 has a main body having a sprocket holding portion that clamps the driven sprocket, and the sprocket holding portion has a fixed-side sprocket holding portion and a swing-side sprocket holding portion. The fixed-side sprocket holding portion has a fixed-side first support portion that supports the driven sprocket placed on the fixed-side sprocket holding portion from below at a first contact point, and a fixed-side second support portion that supports it at a second contact point that is placed outside the first contact point. When the driven sprocket is supported simultaneously by the fixed-side first support portion and the fixed-side second support portion in an upright position, the gravity vector acting on the center of gravity of the driven sprocket is directed between the first contact point and the second contact point. Therefore, the driven sprocket supported simultaneously by the fixed-side first support portion and the fixed-side second support portion will not fall off the sprocket in an upright position even when no chain is wrapped around it, and can always maintain a state in which it is supported by the first contact point and the second contact point in an upright position. Furthermore, the fixed side first support portion is formed so that it moves away from the center of gravity of the driven sprocket when it is supported by the fixed side first support portion and the fixed side second support portion as it approaches the fixed side second support portion.Therefore, even if, for example, it is difficult to change the shape of the fixed side second support portion due to structural reasons, the positions of the first contact point and the second contact point and the center of gravity of the driven sprocket can be easily adjusted simply by changing the shape of the fixed side first support portion.

[0011] According to the configuration of claim 2, when the driven sprocket is supported by the fixed-side first support portion and the fixed-side second support portion simultaneously, the gravity of the driven sprocket acting on the center of gravity of the driven sprocket and , occurs when the chain of the chain guide mechanism is wound around the main body. Because the vector of the resultant force of the tension applied to the driven sprocket is directed between the first and second contact points, even when the tension due to the chain's own weight presses against the driven sprocket, the driven sprocket will not fall off the sprocket holding portion in the upright state, and can always remain supported by the first and second contact points in the upright state.

[0012] Claim 3 According to the configuration described above, the fixed side sprocket holding portion further has a fixed side third support portion that can contact the driven sprocket from above, and the fixed side third support portion is configured to be able to contact the driven sprocket when the driven sprocket disengages from the fixed side second support portion and moves a predetermined amount inward of the fixed side sprocket holding portion.Therefore, even if the chain applies a strong tension to the driven sprocket, the amount of movement can be limited by the fixed side third support portion, and the driven sprocket can be prevented from moving excessively from its predetermined position. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an overall view of a frame 100 of a chain guide mechanism according to an embodiment of the present invention. [Figure 2] 1 is an overall view of a frame 100 of a chain guide mechanism according to an embodiment of the present invention, showing a state in which sufficient tension is applied to the chain. [Figure 3] 1 is an overall view of a frame 100 of a chain guide mechanism according to an embodiment of the present invention, showing a state in which sufficient tension is not applied to the chain. [Figure 4] 1 is an enlarged view of part A of the frame 100 of the chain guide mechanism according to one embodiment of the present invention, in a state in which sufficient tension is not applied to the chain. DETAILED DESCRIPTION OF THE INVENTION

[0014] A frame 100 of a chain guide mechanism according to one embodiment of the present invention will be described below with reference to the drawings. For the sake of explanation, the swing chain guide is not shown in FIGS.

[0015] As shown in Figure 1, the frame 100 of the chain guide mechanism has a main body 110, a top guide 115 provided on the top surface of the main body 110, a fixed chain guide 111 provided on one side of the main body 110, and a swinging chain guide holding part 114 to which a swinging chain guide 112 can be attached on the side of the main body 110 opposite the fixed chain guide 111.A fixed side sprocket holding part 120 is provided on the fixed chain guide 111 side of the top of the main body 110, a swinging side sprocket holding part 130 is provided on the swinging chain guide holding part 114 side of the top of the main body 110, and a drive sprocket holding part 135 capable of holding a drive sprocket DS is provided on the bottom of the main body 110.

[0016] The main body 110 is provided with mounting holes H1, H2, and H3 at various locations for fixing to the engine. The swingable chain guide 112 is swingably attached to a swingable chain guide holder 114 via a swing shaft 113, and is configured to be able to press the chain CH that is wound around it.

[0017] The fixed side sprocket holding portion 120 is configured to be able to hold the fixed side driven sprocket S1, and is provided with a fixed side first support portion 121, a fixed side second support portion 122, and a fixed side third support portion 123 that can support the fixed side driven sprocket S1 at any position and / or clamp it with the chain CH. The fixed side second support portion 122 is provided above the mounting hole H1, the fixed side first support portion 121 is provided more inward than the fixed side second support portion 122, and the fixed side third support portion 123 is provided further inward than the fixed side first support portion 121.

[0018] The oscillating side sprocket holding portion 130 is configured to be able to hold the oscillating side driven sprocket S2, and is provided with a oscillating side first support portion 131 and a oscillating side second support portion 132 that can support the oscillating side driven sprocket S2 at any position and / or clamp it with the chain CH. The swing-side first support portion 131 is provided outside the swing-side second support portion 132 .

[0019] The chain CH surrounds the drive sprocket DS, the fixed driven sprocket S1, and the swinging driven sprocket S2, and is wound around the top guide 115, the fixed chain guide 111, and the swinging chain guide 112.

[0020] Next, a method for holding the fixed driven sprocket S1 by the fixed sprocket holding portion 120 of the frame 100 of the chain guide mechanism according to one embodiment of the present invention will be described with reference to FIGS.

[0021] First, when the chain CH receives a pressing force from the oscillating chain guide 112, it becomes tense as it is pushed toward the main body 110 by the oscillating chain guide 112, and therefore the chain CH is pressed with tension ST in a direction that presses the drive sprocket DS, fixed side driven sprocket S1, and oscillating side driven sprocket S2 against the inside of the drive sprocket holding portion 135, fixed side sprocket holding portion 120, and driven side sprocket holding portion 130, respectively.

[0022] At this time, the fixed side driven sprocket S1 moves slightly inward of the fixed side sprocket holding portion 120 and settles into a position where it is clamped between the chain CH and the fixed side third support portion 123, or a position where it is clamped between the chain CH and the fixed side first support portion 121 and the fixed side third support portion 123, as shown in Figure 2. This allows the fixed driven sprocket S1 to be stably held without falling off the fixed sprocket holding portion 120. Furthermore, the amount of movement of the fixed side driven sprocket S1 when clamped with the chain CH can be adjusted by the amount of protrusion of the fixed side third support portion 123, thereby preventing the fixed side driven sprocket S1 from shifting out of position when attaching the chain guide mechanism to the engine.

[0023] In addition, the oscillating side driven sprocket S2 also moves slightly toward the inside of the oscillating side sprocket holding portion 130 and settles into a position where it is clamped between the chain CH and the oscillating side second support portion 132, or between the chain CH and the oscillating side first support portion 131 and the oscillating side second support portion 132, as shown in Figure 2, and the drive sprocket DS is also pressed toward the inside of the drive sprocket holding portion 135 and is clamped between the chain CH and the drive sprocket holding portion 135.

[0024] Next, the behavior of the fixed driven sprocket S1 when the oscillating chain guide 112 does not press the chain CH sufficiently will be described with reference to FIGS. If the pressure applied to the chain CH by the swingable chain guide 112 is insufficient, the chain CH will slacken by a predetermined amount along the top guide 115 and the fixed chain guide 111 . Furthermore, if the swingable chain guide 112 is not completely released from the chain CH, the chain CH will slacken along the swingable chain guide 112 as well.

[0025] At this time, as shown in Figure 3, the tension applied by the chain CH to the fixed driven sprocket S1, the oscillating driven sprocket S2, and the drive sprocket DS decreases, and a tension ST2 lower than the tension ST1 is applied by the chain CH to the fixed driven sprocket S1.

[0026] If the tension ST2 is insufficient to clamp the fixed side driven sprocket S1 between the chain CH and the fixed side third support portion 123, the fixed side driven sprocket S1 will disengage from the fixed side third support portion 123 and move toward the outside of the fixed side sprocket holding portion 120, coming into contact with the first contact point 121a of the fixed side first support portion 121 and the second contact point 122a of the fixed side second support portion 122, as shown in Figure 4. Unless the shape of the fixed side driven sprocket S1 changes, the first contact point 121a and the second contact point 122a when the fixed side driven sprocket S1 contacts the fixed side first support portion 121 and the fixed side second support portion 122 simultaneously are each fixed at a single point.

[0027] The fixed driven sprocket S1 is subjected to gravity SG and tension ST2 of the chain CH, each of which can be expressed as a force vector from the center of gravity SC of the fixed driven sprocket S1. At this time, if the fixed side driven sprocket S1 is supported by the fixed side first support portion 121 and the fixed side second support portion 122 so that the resultant force MP of gravity SG and chain tension ST2 is directed between the first contact point 121a and the second contact point 122a, as shown in Figure 4, the fixed side driven sprocket S1 will not come off the fixed side sprocket holding portion 120 and will remain supported by the fixed side first support portion 121 and the fixed side second support portion, i.e., the temporary assembled state of the chain guide mechanism, and the fixed side driven sprocket can be easily attached to the engine without any significant deviation in position.

[0028] The positions of the first contact 121a and the second contact 122a can be changed as appropriate by changing the shape of the fixed side first support portion 121 and the fixed side second support portion 122. For example, if the fixed side second support portion 122 is formed near the mounting hole H1, the positions of the first contact 121a and the second contact 122a can be adjusted by forming only the fixed side first support portion 121 so that it moves away from the center of gravity of the fixed side driven sprocket S1 supported by the fixed side first support portion 121 and the fixed side second support portion 122 as it approaches the fixed side second support portion 122. In particular, when the frame 100 of the chain guide mechanism is formed in advance in a predetermined basic shape, simply by cutting the fixed side first support portion 121 into the shape described above, it is possible to prevent the fixed side driven sprocket S1 from falling off from the driven sprocket holding portion 120 regardless of various product specifications, and the installation work on the engine can be carried out efficiently. Furthermore, even when the chain CH is not wrapped around it, as long as the vector of gravity acting on the fixed side driven sprocket S1 is directed between the first contact point 121a and the second contact point 122a, the fixed side driven sprocket S1 will not fall off from the fixed side sprocket holding portion 120 in the upright position.

[0029] The oscillating side driven sprocket S2 also moves slightly outward from the oscillating side sprocket holding part 130 as the chain CH slackens, but the chain CH around which it is wound supports the oscillating side driven sprocket S2 from below along the oscillating chain guide 112 and is also supported by the oscillating side first support part 131, so the oscillating side driven sprocket S2 will not fall off from the oscillating side sprocket holding part 130 in the upright position.

[0030] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design modifications can be made without departing from the present invention as set forth in the claims.

[0031] In the above-described embodiment, the positions of the first contact and the second contact are adjusted by processing only the fixed side first support portion, but the method of adjusting the positions of the first contact and the second contact is not limited to this. For example, the positions of the first contact and the second contact may be adjusted by only changing the shape of the fixed side second support portion, or a third contact may be provided that supports the fixed side driven sprocket simultaneously with the first contact and the second contact. In addition, in the above-described embodiment, the fixed side sprocket holding portion is provided with a fixed side third support portion, and the fixed side driven sprocket is sandwiched between the chain and the fixed side third support portion. However, the configuration of the fixed side sprocket holding portion is not limited to this, and for example, the fixed side third support portion does not need to be provided, and the fixed side driven sprocket may be sandwiched between the chain and the fixed side first support portion.

[0032] In addition, in the above-described embodiment, it has been described that mounting holes are provided near the fixed side second support part, but the number and positions of the mounting holes are not limited to this, and for example, mounting holes may be provided near the oscillating side first support part. In addition, in the above-described embodiment, a top guide is provided on the top surface of the main body and a fixed chain guide is provided on the side of the main body, but the frame configuration of the chain guide mechanism is not limited to this, and for example, there may be no top guide or no fixed chain guide. [Explanation of symbols]

[0033] 100 ··· Chain guide mechanism frame 110 Main body 111 Fixed chain guide 112 Swinging chain guide 113 ··· Oscillating shaft 114 Swinging chain guide holder 115 ··· Top Guide 120 Fixed sprocket holder 121... Fixed side first support part 121a First contact 122 ... Fixed side second support part 122a 2nd contact 123 ... Fixed side third support part 130 ··· Oscillating side sprocket holding portion 131 ··· First support portion on swing side 132 ··· Swing side second support portion 135 Drive sprocket holder S1: Fixed driven sprocket S2: Oscillating side driven sprocket DS ··· Drive sprocket CH Chain H1, H2, H3... Mounting holes SC: Center of gravity of the fixed driven sprocket SG: Gravity acting on the fixed driven sprocket ST1, ST2: Tension from the chain applied to the fixed driven sprocket MP: Resultant force of gravity and tension from the chain acting on the fixed driven sprocket

Claims

1. A frame of a chain guide mechanism having a main body and a sprocket holding portion that supports a driven sprocket, The main body has a swingable chain guide holder to which a swingable chain guide can be attached, and a fixed chain guide, The sprocket holding portion has a fixed-side sprocket holding portion provided on the fixed chain guide side and a swinging-side sprocket holding portion provided on the swinging chain guide holding portion side, the fixed-side sprocket holding portion has at least a fixed-side first support portion that supports the driven sprocket arranged on the fixed-side sprocket holding portion from below at a first contact point, and a fixed-side second support portion that supports the driven sprocket at a second contact point arranged outside the first contact point, when the driven sprocket is supported simultaneously by the fixed-side first support portion and the fixed-side second support portion and placed in an upright position, a vector of gravity acting on the center of gravity of the driven sprocket is directed between the first contact point and the second contact point, A frame of a chain guide mechanism, characterized in that the fixed-side first support portion is formed so that the closer it is to the fixed-side second support portion, the farther it is from the center of gravity of the driven sprocket when it is supported by the fixed-side first support portion and the fixed-side second support portion.

2. 2. The frame of a chain guide mechanism according to claim 1, wherein when the driven sprocket is supported simultaneously by the fixed-side first support portion and the fixed-side second support portion, a vector of a resultant force of the gravity of the driven sprocket acting on the center of gravity of the driven sprocket and the tension acting on the driven sprocket when the chain of the chain guide mechanism is wound around the main body portion is directed between the first contact point and the second contact point.

3. the fixed-side sprocket holding portion further includes a fixed-side third support portion that can contact the driven sprocket from above, 3. A frame for a chain guide mechanism as described in claim 1 or claim 2, characterized in that the fixed-side third support portion is configured to be able to contact the driven sprocket when the driven sprocket disengages from the fixed-side second support portion and moves a predetermined amount inward of the fixed-side sprocket holding portion.

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