JP2004205002A - Chain transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a chain transmitting device capable of preventing the impairing of the assembling performance by inhibiting the increase of the number of pieces of components, and reducing the contact noise. <P>SOLUTION: Sprocket teeth 15 have the taper shape having a thin tooth thickness at an axial one end side of a sprocket and a thick tooth thickness at the other end side, and having the uniform tooth depth. Pin engagement holes 16a of, for example, three link plates 16 arranged in parallel have a dimension enough for the relative movement to a pin 17a of a pin plate. A plurality of link teeth arranged in parallel can be kept into contact with an engagement face with phase difference only by forming the engagement face of the sprocket obliquely to the rotating direction, and the plurality of link teeth laterally arranged are not simultaneously seated on the sprocket teeth, whereby the contact noise (noise in engagement) of the link teeth with the engagement face can be reduced, and the increase of assembling man-hours caused by the increase of the number of pieces of components can be prevented. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chain transmission device such as a camshaft, an oil pump, and a balancer shaft in automobiles and industrial machines.
[0002]
[Prior art]
In a conventional drive chain sprocket, a link plate having a different shape is used so that the contact timing between the link rate and the sprocket is different to reduce noise generated at the time of contact between the two. reference.). Further, there is a type in which teeth having different pressure angles are randomly arranged in a sprocket so as to reduce the meshing sound.
[0003]
[Patent Document 1]
JP 2002-250406 A
[Problems to be solved by the invention]
In the drive chain sprocket described above, a plurality of link plates having different shapes are manufactured and assembled, and thus there is a problem that the number of parts increases and the number of assembling steps increases. In addition, in the case where the pressure angles of the sprocket teeth are randomly arranged, different teeth are arranged in one sprocket, and there is a problem that the sprocket cannot be manufactured by ordinary gear cutting.
[0005]
[Means for Solving the Problems]
In order to solve such a problem, and to realize a chain transmission device capable of suppressing an increase in the number of parts, preventing deterioration of assemblability and reducing contact noise, the present invention employs the same shape. An endless chain (9.10) in which a plurality of link plates (16) arranged in parallel are connected to each other via a pin plate (17), and the chain (9.10) is wound. A chain transmission having a sprocket (3, 4, 6, 8) to be engaged, wherein said link plate (16) has a bifurcated engagement with sprocket teeth (15) of said sprocket (3, 4, 6, 8). A linking tooth (16b) and a pin engaging hole (16a) for inserting a pin (20) connecting the pin plate (17), and the link tooth of the sprocket tooth (15). A meshing surface (15a) meshing with the sprocket (16b) is formed so as to face obliquely with respect to the rotation direction of the sprocket (3, 4, 6, 8), and each link in the link plate row is formed on the meshing surface (15a). The pin engagement hole (16a) is relatively moved between the pin (20) and at least the rotation direction of the sprocket (3, 4, 6, 8) so that the teeth (16b) abut with a phase difference. It is assumed that it is formed in a possible size.
[0006]
According to this, a plurality of link teeth arranged in parallel with each other can be relatively moved with respect to the pins of the pin plate simply by forming the engagement surface of the sprocket so as to face obliquely with respect to the rotation direction. , Because a plurality of link teeth arranged side by side do not seat on the sprocket teeth at the same time, so that the contact sound of the link teeth with the meshing surface (noise at the time of meshing) is reduced. And the number of parts is not increased, and the number of assembling steps is not increased.
[0007]
In addition, according to the sprocket teeth (15) having a tooth thickness shape that radially spreads from one end in the axial direction of the sprocket (3, 4, 6, 8) to the other end, the rotation of the sprocket teeth Since the tooth thickness in the direction is different, when a plurality of link plates of the same shape mesh with the sprocket teeth, the height of the link plates riding on the sprocket teeth will be different. Thus, the timing at which the link plate contacts the sprocket teeth can be adjusted in the height direction by adding the timing to the rotation direction. Therefore, even if the radial shape (taper angle) of the tooth thickness is not extremely increased, the timing at which the link plate abuts can be appropriately set, and the sprocket can be downsized. Also, since each link tooth comes into contact with the sprocket tooth in the direction of rotation of the sprocket from the side where the thickness of the sprocket tooth is larger, the point where the link plate first contacts the sprocket is compared with the point where the other link plates contact. High rigidity improves durability.
[0008]
Further, it is preferable that the sprocket (3, 4, 6, 8) is attached to one end of a rotating shaft (2, 5, 7) with the side having the smaller tooth thickness facing the chain case (13). According to this, the side with the smaller tooth thickness is directed toward the chain case side, and the side with the larger tooth thickness is directed toward the engine body side, so that the side with the larger tooth thickness at which the noise generated when the chain hits the sprocket increases. Is moved away from the chain case, so that radiated sound transmitted through the chain case can be reduced.
[0009]
A lubricating oil supply hole (18a) for supplying lubricating oil to a meshing portion between the sprocket (3, 4, 6, 8) and the chain (9, 10) is provided in the chain case (13). In addition, according to the opening in the direction of discharging the lubricating oil toward the meshing portion, the lubricating oil is supplied from the side of the link plate that comes into contact with the sprocket teeth with a delay. Even when the contact timings of the sprocket teeth are different from each other, the lubricating oil can be sufficiently supplied to the contact portion between the link plate and the sprocket teeth without being interrupted (disturbed) by the link plate that contacts first.
[0010]
Further, the sprocket (3, 4, 6, 8) is attached to one end of a rotating shaft (2, 5, 7) with the side having the smaller tooth thickness facing the cylinder block (1), and the sprocket ( A position where a lubricating oil supply hole for supplying lubricating oil to a meshing portion of the chain (3, 4, 6, 8) and the chain (9, 10) is provided in the cylinder block (1) and faces the meshing portion. It is preferable that the opening is provided in such a direction as to release the lubricating oil toward the engagement portion. According to this, since the lubricating oil is supplied from the link plate that comes into contact with the sprocket teeth with a delay, even if the contact timing between the link plate and the sprocket teeth is different, the link plate that comes in contact with the sprocket teeth is cut off first. The lubricating oil can be sufficiently supplied to the contact point between the link plate and the sprocket teeth without being disturbed, and the lubricating oil supply hole is provided at a position facing the meshing portion, so that the meshing is ensured. The lubricating oil can be supplied to the section.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on specific examples shown in the accompanying drawings.
[0012]
FIG. 1 is a diagram showing an end face on one axial end side of a crankshaft in an engine to which the present invention is applied. As shown in FIG. 2, a large-diameter sprocket 3 coaxially integrated with a protruding end portion of a crankshaft 2 serving as a rotation shaft protruding from one end surface 1a of a cylinder block 1 constituting the engine, and A small diameter sprocket 4 is fixed, a large sprocket 6 having the same diameter is fixed to each end of a camshaft 5 as a pair of rotating shafts, and a small sprocket 8 is fixed to one end of an oil pump shaft 7 as a rotating shaft. ing.
[0013]
A chain 9 is wound around the small diameter sprocket 4 and the pair of large sprockets 6, and a chain 10 is wound around the large diameter sprocket 3 and the small sprocket 8. Chain guides 11a and 11b and tensioners 12a and 12b are disposed at appropriate positions between the corresponding sprockets 3, 4, 6, and 8 of the chains 9, 10. A chain case 13 is attached to the entire end face of the engine shown in FIG. 1 so as to cover both chains 9 and 10, as shown in FIG. The crankshaft 2 protrudes outside the chain case 13, and a pulley 14 for belt-driving an auxiliary device such as a generator is fixed to the protruding end.
[0014]
The sprocket teeth of the sprockets 3, 4, 6, and 8 may be similarly formed except for the size corresponding to each of the chains 9 and 10. The sprocket 3 and the corresponding chain 10 are shown. It should be noted that dimensions are exaggerated in the drawings which are explanatory diagrams relating to the meshing state.
[0015]
FIG. 3 is an enlarged view of the sprocket teeth 15 of the large diameter sprocket 3. Note that the upper side in the figure is the chain case 13 side. As shown in FIG. 3, the sprocket teeth 15 are formed such that the tooth thickness in the axial direction of the sprocket 3, that is, the tooth width in the rotation direction of the sprocket 3, increases or decreases. As a result, the meshing surface 15a of the sprocket teeth 15 is formed as a tapered surface that is inclined with respect to the rotation direction of the sprocket 15. Also, the tips of the sprocket teeth 15 are formed in a tapered shape so that the outer peripheral surface passing through each of the tips forms a part of a conical surface having an upper vertex in FIG.
[0016]
FIG. 4 is an explanatory view of the sprocket teeth 15 as viewed from above in FIG. 3, and shows a tooth thickness a1 at one end in the axial direction of the sprocket 3 (for example, an arc tooth thickness on a base circle of a gear) at the other end. This shows that the tooth thickness a2 is increased. The dimension changes only in the tooth thickness, and the tooth height (for example, the effective tooth height in a gear) b is set so that the portion between the tooth thickness a1 and the tooth thickness a2 is all the same. For example, the sprocket 3 may be formed such that the taper angles of the tooth tip 15b and the tooth bottom 15c are the same, and the tooth thickness is gradually increased from one end of the sprocket 3 in the axial direction to the other end.
[0017]
FIG. 5 shows a chain 10 that meshes with the sprocket 3. The chain 10 has a bifurcated shape and a link plate 16 having link teeth at both ends, a pin plate 17 also formed in a bifurcated shape, and a bifurcated shape. The guide plate 19 and the guide plate 19 facing opposite to the plate 17 are respectively arranged in one row, and the respective rows of the link plate 16 and the pin plate 17 are alternately arranged in parallel between a pair of guide plate 19 rows. I have. In the illustrated example, four rows of pin plates 17 and three rows of link plates 16 between the rows are arranged between two rows of guide plates 19 located on both sides of the chain 10.
[0018]
Pin support holes 17a are provided at both ends of the pin plate 17 in the row direction, and pin support holes 19a are provided at both end portions of the guide plate 19 in the row direction. The pins 20 are inserted into the pin support holes 17a and 19a with a predetermined tolerance. The link plate 16 is provided with a pin engagement hole 16a having a diameter larger than that of the pin 20 so that the pin 20 can penetrate with a predetermined gap (play).
[0019]
Then, as shown in FIG. 5, the pins 20 are inserted into the support holes 19a and 17a and the pin engagement holes 16a of the guide plate 19, the pin plate 17 and the link plate 16 which are arranged in parallel. 17 and 16 are connected via a pin 20, and each head, which is both ends of the pin 20, is caulked into a pin support hole 19 a of each guide plate 19, so that each link plate 16, each pin plate 17 and each The guide plate 19 is integrated. Thus, the endless annular chain 10 in which three rows of the link plates 16 are arranged between the four rows of the pin plates 17 is formed between the guide rows 19 of the outer rows.
[0020]
Next, the manner of engagement between the sprocket 3 and the link plate 16 will be described below with reference to FIG. FIG. 6A shows a state where the link plate 16 on the right side of the figure has started to mesh with the sprocket teeth 15 when the sprocket 3 rotates in the direction indicated by the arrow A in the figure. Further, in the drawing, the back side of the paper surface is the cylinder block 1 side, and the taper of the sprocket teeth 15 extends from the near side of the paper surface to the back side.
[0021]
At the beginning of the engagement shown in FIG. 6A, the link teeth on the front side in the traveling direction of the pin plate 17 on the innermost side in the drawing come into contact with the sprocket teeth 15 first due to the tapered shape of the sprocket teeth 15. A gap is provided between the pin engagement hole 16a of the link plate 16 and the pin 20, and the link plate 16 can be freely displaced to some extent with respect to the position of the pin 20. 6A, the link teeth 16b on the front side in the traveling direction of the link plates 16 can be located in a state of being relatively lifted with respect to the sprocket teeth 15.
[0022]
FIG. 7A shows a state in which the front link teeth 16 b of the rear link plate 16 in the traveling direction in FIG. As described above, when the link plate 16 starts to mesh with the sprocket teeth 15, only the link teeth 16 b of the link plate 16 (the left side in FIG. 7A) corresponding to the portion having a large tooth thickness due to the taper of the sprocket teeth 15 are in contact. Can touch.
[0023]
As the rotation of the sprocket 3 proceeds, the link teeth 16b of the intermediate link plate 16 abut on the intermediate portion of the tapered surface of the sprocket teeth 15 as shown in FIG. 7B. At this time, the link plate 16 on the near side also approaches the sprocket teeth 15, but the link teeth 16b are not in contact with each other due to the tapered shape. When the sprocket 3 rotates until it becomes as shown in FIG. 6B, the link teeth 16b of the link plate 16 on the near side also come into contact with the sprocket teeth 15 as shown in FIG.
[0024]
As described above, since the link teeth 16b of the three rows of link plates 16 abut against the sprocket teeth 15 with a phase difference, in the conventional sprocket teeth having straight-shaped meshing surfaces, a loud noise is generated by simultaneous abutment. On the other hand, noise at the time of meshing is reduced. Also, the number of components due to the combination of the link plate 16 and the pin plate 17 is not different from the conventional one, and there is no increase in the number of components or increase in product cost due to an increase in the number of assembly steps.
[0025]
As shown in FIG. 2, a lubricating oil passage 18 is provided in the chain case 13, and a lubricating oil supply hole 18 a serving as an outlet of the lubricating oil is directed toward a meshing portion between the sprocket 3 and the chain 10. Has been established. As a result, lubricating oil pumped from an oil pump (not shown) is discharged toward the meshing portion between sprocket 3 and chain 10.
[0026]
As described above, the side of the sprocket tooth 15 where the tooth thickness is smaller is located on the chain case 13 side, so that the lubricating oil is supplied from the link plate 16 side which comes into contact with the sprocket tooth 15 with a delay. Therefore, even if the contact timing between the link plate 16 and the sprocket teeth 15 is different, all the contact portions between the link plate 16 and the sprocket teeth 15 are not interrupted (disturbed) by the link plate 16 that contacts first. Lubricating oil can be supplied.
[0027]
The lubricating oil passage is not limited to the lubricating oil passage provided in the chain case 13 of the above example. For example, a lubricating oil passage 23 is provided in the cylinder block 1 as shown by an imaginary line in FIG. The lubricating oil supply hole 23a serving as an oil outlet may be opened toward the meshing portion between the sprocket 3 and the chain 10 as described above. Even in this case, the lubricating oil is discharged toward the meshing portion between the sprocket 3 and the chain 10. In this case, by setting the side of the sprocket tooth 15 where the tooth thickness is small to the cylinder block 1 side, the same operation and effect as described above can be obtained.
[0028]
The contact order of the three link plates 16 arranged in parallel with the sprocket teeth 15 is such that the sprocket teeth 15 come into contact starting from the portion having the largest tooth thickness, and are arranged in the order of FIGS. 7 (a), (b) and (c). Become. That is, the portion where the link plate 16 first comes into contact is a portion having a large tooth thickness, and thus the link plate 16 first comes into contact with the portion having the highest rigidity, so that the durability can be improved.
[0029]
Further, in the cross section of the sprocket teeth 15 in the rotation direction of the sprocket 3, the curvature at the tip (top) of the sprocket teeth 15 is such that the curvature of the sprocket teeth 15 when viewed from the tip end side of the sprocket teeth 15 expands in a C shape (the axis of the sprocket 3 (The other end in the direction). For this reason, the link plate 16 abuts on the sprocket teeth 15 on the radially outer side of the sprocket 3 and is fixed in position on the side where the C-shape spreads. The timing (including the contact sound) can be shifted in a direction to delay.
[0030]
Therefore, by making the engagement surface of the sprocket teeth 15 in a C shape when viewed from the tooth tip side, the timing of the contact sound can be shifted even if the taper angle formed on the sprocket teeth 15 is reduced. Therefore, by reducing the taper angle of the sprocket teeth 15, the width (teeth thickness) of the sprocket teeth 15 in the rotation direction on the widening side can be reduced, so that the diameter of the sprocket 3 can be reduced. The size can be reduced.
[0031]
Next, a second example based on the present invention will be described below. In the second example, as shown in FIG. 8, the outer peripheral surface of the sprocket 21 corresponding to the sprocket 3 has a straight shape while the sprocket 3 has a tapered shape. I have. The sprocket teeth 22 are formed so as to have a meshing surface 21a formed of a tapered surface having a small tooth thickness at one axial end (upper side in the figure) of the sprocket 3 and a large tooth thickness at the other axial end. . Therefore, the width of the tooth space between the sprocket teeth 22 is large at one axial end of the sprocket 3 and is small at the other axial end.
[0032]
As shown in FIG. 9, the teeth b (for example, the effective teeth of the gears) of the sprocket teeth 22 have the same length at one end and the other end in the axial direction of the sprocket 3. Thus, as described above, the outer peripheral surface of each of the sprockets 21 passing through the respective ends forms a cylindrical surface.
[0033]
FIG. 10 shows the manner of engagement between the sprocket 21 and the link plate 16 in the second example. FIG. 10A shows a state in which the link plate 16 is in contact with a portion of the sprocket tooth 22 where the tooth thickness is large, and FIG. FIG. 10C shows a state in which the link plate 16 is in contact with the portion of the sprocket tooth 22 where the tooth thickness is small. As can be seen from the drawings, the height of each link plate 16 with respect to the sprocket teeth 22 at the time of meshing varies depending on the difference in tooth thickness. As a result, the link plate 16 and the sprocket 22 are brought into contact with the timing difference between the rotation direction of the sprocket 21 and the sprocket 22, and at the same time, they are brought into contact with a difference in the height direction. Thereby, the adjustment range of the contact timing can be expanded. Therefore, the contact timing of the link plate 16 can be appropriately set without extremely increasing the angle of the taper that makes the tooth thickness different, so that the sprocket 21 can be downsized.
[0034]
Similarly to the first example, the order in which the three link plates 16 arranged in parallel abut on the sprocket teeth 22 comes in contact with the sprocket teeth 22 starting from the portion where the tooth thickness is large, and FIG. b) and (c). That is, the portion where the link plate 16 first comes into contact is a portion having a large tooth thickness, and thus the link plate 16 first comes into contact with the portion having the highest rigidity, so that the durability can be improved.
[0035]
In the illustrated example, a chain transmission for driving a camshaft of an automobile engine and an oil pump is shown. However, the present invention is not limited to this, and a chain transmission using a chain and a sprocket. As long as it is applicable, the present invention can also be applied to a balancer shaft drive transmission and an industrial machine.
[0036]
When the present invention is applied to an engine, the present invention is also applicable to an engine for a marine propulsion device such as an outboard motor having a vertical crankshaft.
[0037]
【The invention's effect】
As described above, according to the present invention, since a plurality of link teeth arranged in parallel to each other do not simultaneously seat on the sprocket teeth, it is possible to reduce the contact noise (noise at the time of meshing) between the link teeth and the meshing surface of the link teeth. There is no increase in the number of parts and the number of assembling steps.
[0038]
In addition, according to the sprocket teeth having a tooth thickness shape that radially spreads from one end in the axial direction of the sprocket to the other end, the height at which the sprocket teeth ride on the link plate differs, so that the link plate The timing of contact with the sprocket teeth can be adjusted in the height direction in addition to the rotation direction, and the contact timing of the link plate can be adjusted as appropriate without excessively increasing the radial shape (taper angle) of the tooth thickness. And the sprocket can be downsized. In addition, since each link tooth comes into contact with the sprocket tooth from the side where the tooth thickness is large, the rigidity of the portion where the link plate first comes into contact with the sprocket is high, so that the durability is improved.
[0039]
In addition, according to the sprocket being attached to one end of the rotating shaft with the side with the smaller tooth thickness facing the chain case side, the side with the smaller tooth thickness faces the chain case side, and the side with the larger tooth thickness faces the engine body. Since it is directed to the side, the side having a large tooth thickness, at which the noise generated when the chain collides with the sprocket, is kept away from the chain case, and the radiated sound transmitted through the chain case can be reduced. Further, by providing the lubricating oil supply hole in the chain case and opening the lubricating oil in a direction to discharge the lubricating oil toward the meshing portion, the lubricating oil is supplied from the link plate side which comes into contact with the sprocket teeth with a delay, Even when the contact timing between the link plate and the sprocket teeth is different, the lubricating oil can be sufficiently supplied to the contact portion between the link plate and the sprocket teeth without being interrupted (disturbed) by the link plate that contacts first. . Also, the sprocket is attached to one end of the rotary shaft with the side having the smaller tooth thickness facing the cylinder block, and a lubricating oil supply hole is provided in the cylinder block, and the lubricating oil is discharged toward the meshing portion at a position facing the meshing portion. Orientation may be established, and in this case, the same effect as above can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an end face on one end side in an axial direction of a crankshaft in an engine to which the present invention is applied.
FIG. 2 is a view taken along the arrow II-II line in FIG. 1;
FIG. 3 is an enlarged perspective view of a main part showing a sprocket tooth according to the present invention.
FIG. 4 is an explanatory view showing the shape of the sprocket teeth as viewed from the arrow IV line in FIG. 3;
FIG. 5 is an exploded perspective view showing the chain.
6A is a diagram showing the start of engagement of link plates with sprocket teeth, and FIG. 6B is a diagram showing the engagement state of all link plates.
FIG. 7A is a cross-sectional view of an essential part taken along line VIIa-VIIa of FIG. 6A, showing an initial state of contact of the link plate with the sprocket teeth, and FIG. It is a figure corresponding to (a) which shows a state in the middle stage of contact, and (c) is an important section sectional view seen along arrow VIIc-VIIc line of Drawing 6 (c) which shows a state of contact end.
FIG. 8 is a perspective view of a sprocket showing a second example.
FIG. 9 is an enlarged view of a main part as viewed from the arrow IX line in FIG. 8;
10A is a diagram illustrating a contact state of a link plate with a portion having a large tooth thickness in a second example, and FIG. 10B is a diagram illustrating a contact state of an intermediate portion with a tooth thickness in a second example. FIG. 4C is a diagram showing a contact state with a portion having a small tooth thickness.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder block 3.4.6.8 Sprocket 9.10. Chain 13 Chain case 15 Sprocket teeth 15a Meshing surface 16 Link plate 16a Pin engaging hole 16b Link tooth 17 Pin plate 20 Pin 18a Lubricating oil supply hole 23a Lubricating oil supply hole

Claims (5)

A chain transmission device having an endless chain in which a plurality of link plates having the same shape are arranged in parallel with each other and linking a row of link plates via a pin plate, and a sprocket for winding the chain,
The link plate includes a bifurcated link tooth that engages with a sprocket tooth of the sprocket, and a pin engagement hole for inserting a pin that connects between the pin plate and the pin plate.
An engaging surface that meshes with the link teeth of the sprocket teeth is formed so as to face obliquely with respect to the rotation direction of the sprocket,
The pin engagement hole is formed to have a size that allows relative movement in the rotational direction of the sprocket between the pin and the pin so that the link teeth of the link plate row abut on the engagement surface with a phase difference. Chain transmission characterized by the following. The chain transmission according to claim 1, wherein the sprocket teeth have a tooth-thick shape that radially extends from one end of the sprocket in the axial direction to the other end. The chain transmission according to claim 1 or 2, wherein the sprocket is attached to one end of a rotating shaft with the side having the smaller tooth thickness facing the chain case. A lubricating oil supply hole for supplying lubricating oil to a meshing portion between the sprocket and the chain is provided in the chain case, and is opened in a direction to discharge the lubricating oil toward the meshing portion. The chain transmission according to claim 3, wherein The sprocket is attached to one end of a rotating shaft with the side having the smaller tooth thickness facing the cylinder block, and a lubricating oil supply hole for supplying lubricating oil to a meshing portion between the sprocket and the chain is provided on the cylinder block. 3. The chain transmission according to claim 1, wherein the chain transmission device is provided at a position facing the meshing portion and is opened in a direction of discharging the lubricating oil toward the meshing portion. 4.

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