JP2019060347A - Bush-less roller chain and timing chain transmission device - Google Patents

Abstract

To reduce noise and a power loss by properly setting specifications of a bush-less roller chain.SOLUTION: A roller 13 is directly supported to a pin 12. The pin 12 is rotatably supported to a through-hole 16 of an inner link plate 17. A pin outer diameter d and a roller outer diameter D are set within a range of 0.35P≤d≤0.45P, 0.60P≤D≤0.70P relative to a chain pitch P. Thus, a small chain pitch of 4.5 to 5.0 [mm] is allowed and noise and a power loss are reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transmission chain suitable for use with relatively light loads and high-speed rotation in a lubricating environment, and more particularly, a bushless roller chain directly supporting a roller on a pin and the bushless roller chain The present invention relates to a timing chain transmission.

  Conventionally, an inner link in which both ends of a pair of inner link plates are connected by bushings and a roller is loosely fitted rotatably around the bush, and an outer link in which both ends of a pair of outer link plates are connected by pins A roller chain in which pins are inserted into the bushing and alternately and endlessly connected is known. A bushless roller chain has been devised in which a bush is omitted from the roller chain, and an inner link plate is rotatably fitted on the pin of the outer link and the roller is freely loosely fitted on the pin (Patent Document 1) reference).

  Since the bushless roller chain is basically based on omitting the bush from the roller chain as in the bush chain obtained by omitting the roller from the above roller chain, the specifications such as pitch are set based on the roller chain. Therefore, when the roller starts meshing with the sprocket teeth, a large impact force acts on the roller and the pin, resulting in a problem that the durability of the roller and the pin is reduced.

  In order to solve the above-mentioned problem, the above Patent Document 1 forms a predetermined gap in the radial direction between the (connection) pin and the insertion hole of the inner link plate, and the lubricating oil is formed between the predetermined gap and the pin and the roller. The shock absorbing function played by the oil film reduces the impact when the roller starts meshing with the sprocket teeth, thereby improving the durability of the bushingless roller chain.

JP, 2013-44386, A

  Since the above-mentioned bushless roller chain is based on the specifications of the roller chain, the outer diameter (d) of the pin and the outer diameter (D) of the roller are set relatively smaller than the chain pitch (P). It is difficult to make the chain pitch (P) equal to or less than a predetermined value (for example, 6.35 mm) in order to provide a predetermined transmission capability. The bushless roller chain has a chain pitch (P), which is the distance between the leading pin and the next pin, equal to that of the roller chain and the bushing chain, with respect to the pin outer diameter (d) and the roller outer diameter (D). Since the roller collides with the tooth bottom of the sprocket with a relatively long swing radius, a relatively large impact force acts between the pin and the insertion hole of the inner link plate and between the pin and the roller. It can not be absorbed enough.

  Further, the above-described bushingless roller chain is used in a timing chain transmission disposed in the engine. The timing chain transmission has a chain tensioner device and a fixed chain guide device consisting of an arcuate long shaped guide lever extending along the chain, and the bushless roller chain has a circle on the back of the inner link plate. A contact portion formed in an arc shape is guided in sliding contact with the guide lever. For this reason, even under a lubricating environment, the bushless roller chain is guided in sliding contact with the long guide levers of the chain tensioner device and the fixed chain guide device, so that the power loss due to the friction is large.

  Therefore, the present invention sets the specifications suitable for the structure of the bushless roller chain, thereby reducing noise and loss horsepower, and reducing the power loss of the timing chain transmission using it, as described above. It is an object of the present invention to provide a bushless roller chain and timing chain transmission device that solves the problems.

In the present invention, an outer link (15) is formed by connecting both ends of a pair of outer link plates (11) with pins (12) and rotatably supporting rollers (13) on the pins.
And an inner link (19) comprising at least two inner link plates (17) each having an insertion hole (16) through which the pin (12) is rotatably inserted at both ends.
The inner link plate is disposed between the outer link plate (11) and the roller (13), and the pin (12) is inserted through the insertion hole (16) to form the outer link (15) and the outer link (15). In the bushless roller chain (5) in which the inner links (19) are alternately and endlessly connected,
Let P be the chain pitch which is the center-to-center distance between the adjacent pair of pins (12), d be the outer diameter of the pins (12), and D be the outer diameter of the roller (13)
0.35P ≦ d ≦ 0.45P
0.60 P ≦ D ≦ 0.70 P,
It is in the bushless roller chain that is characterized.

  Preferably, the outer diameter d of the pin is 0.40P ≦ d ≦ 0.45P.

  The chain pitch P is in the range of 4.0 to 5.0 [mm].

  The surface of the pin (12) is coated with a hardened layer of metal carbide or vanadium carbonitride.

For example, referring to FIG. 1, the present invention relates to a crank sprocket (2) connected to a crankshaft of an engine;
A cam sprocket (3) connected to a camshaft of the engine;
A timing chain (5) comprising the bushless roller chain wound between the crank sprocket (2) and the cam sprocket (3);
A tensioner (6) comprising: a rotating body (8) in rolling contact with the timing chain; and biasing means for applying a biasing force to the rotating body;
A guide rotating body (9) rotatably supported and rollingly contacting the timing chain to guide the timing chain;
Timing chain transmission (1) with

  The reference numerals in the above parentheses are for comparison with the drawings, but this does not affect the description of the claims at all.

  In the present bushingless roller chain according to claim 1, the roller is inserted through the pin, and the pin outer diameter d is in the range of 0.35P to 0.45P with respect to the chain pitch P, and the roller outer diameter D is 0 As it is in the range of 60 P to 0.70 P, the chain pitch can be set small while securing the meshing of the sprocket teeth properly, and the impact energy can be reduced to reduce the noise level, Power loss can be reduced. Even with the small pitch, the pin 12 is directly supported in the insertion hole of the inner link plate, so a large dangerous cross section can be obtained, and the thickness of the roller is secured to maintain the impact fatigue strength, thereby achieving predetermined transmission. Torque capacity can be secured. Furthermore, the present bushingless roller chain has few parts and is easy to assemble, and can provide high quality products at a low price.

  According to the second aspect of the present invention, a small pitch such as, for example, a chain pitch of 4.76 [mm] is possible, and a transmission with relatively light load and high speed rotation, for example, a timing chain of a two-wheeled vehicle engine. It is suitable for a chain and can transmit a predetermined torque capacity with low noise and small power loss.

  According to the third aspect of the present invention, noise can be reduced and power loss can be reduced by using the chain pitch P as small as 4.0 to 5.0 [mm].

  According to the invention of claim 4, in the present bushingless roller chain, since the pin is in direct sliding contact with the insertion hole of the inner link plate, the sliding contact area becomes small, and there is a possibility that the wear of the pin may cause elongation. The pin surface can be coated with a hardened layer to inhibit chain elongation due to pin wear.

  According to the fifth aspect of the present invention, since the present bushingless roller chain is used for the timing chain transmission, in addition to the reduction of noise and power loss due to the reduction of the pitch, the tensioner and the guide are rotating bodies. Friction loss can be reduced to reduce power loss as a timing chain transmission.

The disassembled perspective view which shows the timing chain transmission which applied the bushless roller chain which concerns on this invention. The top view which showed the bushless roller chain which concerns on this invention in the partial cross section. The front view which shows the bushless roller chain which concerns on this invention. It is a figure which shows the bush chain as a comparative example, (a) is the top view which carried out the partial cross section, (b) is a front view. It is a figure which shows the silent chain as a comparative example, (a) is the top view which carried out the partial cross section, (b) is a front view. The figure which shows the main specifications and basic performance of each chain. The figure which shows the single noise level comparative example of each chain. The figure which shows the loss horsepower of each chain system (chain transmission).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The timing chain transmission device 1 for a two-wheeled engine to which the present invention can be applied includes a crank sprocket 2 connected to a crankshaft, a cam sprocket 3 connected to a camshaft, and both of them as shown in FIG. And a bushless roller chain 5 wound around the sprockets 2 and 3. A tensioner 6 is disposed on the outside on the loose side near the crank sprocket 2 in the bushless roller chain 5, and a guide roller 9 is disposed on the inner side between the two sprockets 2 and 3.

  The tensioner 6 has an arm 10 rotatably supported by a support shaft 4 provided on the engine body, and a tension sprocket 8 is rotatably supported at the tip of the arm. At the other end of the arm, a protrusion 10a protrudes, and a biasing means such as a spring or oil pressure abuts on the protrusion 10a to bias the tension sprocket 8 to the A portion of the bushingless roller chain 5. ing. Therefore, the tensioner 6 abuts the tension sprocket 8 with the predetermined biasing force from the outside to the inside of the loose side of the bushingless roller chain 5 to remove the looseness of the chain. The tensioner 6 may allow movement on the loosening removal side and restrict movement in the opposite direction by means of a saw blade shaped claw, a check valve, screw connection or the like. The guide roller 9 abuts against the inside of the tension side of the bushless roller chain 5 and guides the chain so as to stably travel. The tension sprocket 8 may be a roller, and the guide roller 9 may be a sprocket, and both of them may be a rotating body that rotates in contact with the chain.

  In the bushless roller chain 5 according to the embodiment of the present invention, as shown in FIG. 2 and FIG. 3, the pins 12, 12 are connected to both end portions of the pair of outer link plates 11, 11. It comprises an outer link 15 in which the roller 13 is loosely fitted, and an inner link 19 consisting of a pair of inner link plates 17, 17 having insertion holes 16, 16 through which the pin 12 is inserted at both ends. With the roller 13 in between, the inner link plates 17 and 17 on both sides thereof, and with the outer link plate 11 aligned on both sides, the fitting holes of the pair of outer link plates 11 in a straight line 20, the pin 12 is penetrated through the insertion hole 16 of the pair of inner link plates 17 and the engagement hole 21 of the roller 13, and the both ends of the pin are removed by caulking or the like to obtain the outer link 15 The bushless roller chain 5 is assembled by alternately and endlessly connecting the inner links 19.

  The pin 12 of the bushless roller chain 5 is coated on its surface with a hardened layer of at least one of metal carbides such as chromium (Cr), vanadium (V), titanium (Ti) and niobium (Nb). . For example, a hardened layer made of CrC or VC is formed, and the metal carbide is formed by diffusion and permeating treatment such as chromizing treatment and banizing treatment. Preferably, a pin base material containing 0.6% or more of chromium is subjected to diffusion infiltration in a vanadium-containing gas atmosphere, and a surface layer made of vanadium carbide and a boundary made of a composite carbide of vanadium and chromium are provided. The chromium carbide content is greatest at the interface with the pin base material and gradually decreases toward the surface.

  Alternatively, the pin 12 of the bushingless roller chain 5 is coated on its surface with a hardened layer of vanadium carbonitride (VCN) consisting of vanadium (V), carbon (C) and nitrogen (N). The VCN is formed by performing diffusion penetration treatment in a gas atmosphere containing vanadium, and further nitriding in a nitrogen atmosphere at a temperature of 1000 ° C. or more.

  The bushless roller chain 5 has no bush in comparison with the conventional roller chain and bush chain, and the pin diameter becomes larger with respect to the chain pitch P which is the center distance between a pair of adjacent pins. The outer diameter d of the pin is 0.35 · P to 0.45 · P (0.35P ≦ d ≦ 0.45P), preferably 0.40 · P to 0.45 · P (0.40 P ≦ d ≦ 0.45 P). The diameter of the pin insertion hole 16 of the inner link plate 17 is slightly larger than the outer diameter d of the pin, and is rotatable (pivotable) with respect to the pin 12 in a slippery environment. The pitch Pi at the inner link 19 and the pitch Po at the outer link are substantially equal, even in the state in which. The chain pitch P is less than 6.00 mm, preferably 4.0 to 5.0 mm. The outer diameter D of the present bushingless roller chain 5 is 0.60 · P to 0.70 · P with respect to the pitch P (0.60P ≦ D ≦ 0.70P).

  The timing chain transmission 1 transmits the rotation of the crank sprocket 2 connected to the crankshaft to the cam sprocket 3 through the timing chain consisting of the bushless roller chain 5, and reduces the camshaft to 1⁄2. Rotate. During the transmission, the bushless roller chain 5 rotates relative to each other in the state where the pin 12 and the insertion hole 16 of the inner link plate 17 interpose lubricating oil, and travels while the inner link 19 and the outer link 15 bend. The above-mentioned bushless roller chain 5 has a tension sprocket 8 in contact with the outside on the loose side and is given a predetermined tension, and a guide roller 9 is guided in the inside and guided therein, and there is no disengagement of the chain. The predetermined traveling posture is stably held.

  Since the tension sprocket 8 and the guide roller 9 roll in rolling contact with the chain 5, friction loss is small as compared with a silent chain to be described later, which is in sliding contact with the tensioner lever and the fixed guide. Therefore, the timing chain transmission 1 by the present bushingless roller chain 5 can reduce the system driving loss horsepower.

The bushless roller chain 5 has a smaller pitch P with respect to the pin outer diameter d than the conventional roller chain, bush chain, silent chain and bushless roller chain, and has small impact energy when the roller 13 meshes with sprocket teeth. That is, the impact energy E at the time of the meshing of the chain is
E = Co m P ² R ² cos ² θ (1)
It becomes. Here, Co: constant, m: mass per unit pitch, P: chain pitch, R: sprocket rotation speed, θ: collision incident angle.

  The impact energy E causes the generation of noise of this type of chain, and there is the following relationship between the impact energy E / Eo and the noise level difference I due to the difference in chain specification.

I [dB] = 10 · log ₁₀ (E / Eo) (2)
Therefore, in a roller chain, a bushing chain, and a bushingless roller chain having the same form of collision incident angle θ, the chain pitch P greatly affects the generation of noise, and has equivalent strength and transmission torque capacity, The present bushingless roller chain 5 with 0.35 P ≦ d ≦ 0.45 P and 0.60 P ≦ D ≦ 0.70 P described above can significantly suppress the noise level. In the silent chain, the impact energy E is small because the collision incident angle θ in the equation (1) is large, and therefore noise is reduced. However, the present bushingless roller chain 5 has the above-mentioned chain pitch P and unit The mass m per pitch can be reduced, and the noise can be lower than that of the silent chain in the same strength or high torque range as the silent chain of the transfer torque capacity.

  If the pin outer diameter d is smaller than 0.35P, the strength of the pin is insufficient and a predetermined torque capacity can not be secured. If it is larger than 0.45P, the chain pitch P can not be shortened, and both are desired. Since a small chain pitch can not be obtained, a predetermined noise level can not be reduced. Further, when the roller outer diameter D is smaller than 0.60 P, the impact fatigue strength of the roller can not be obtained, and the predetermined durability of the chain can not be obtained, and when it is 0.70 P or more, the predetermined chain pitch P can be obtained. In any case, a desired small chain pitch can not be obtained, and a predetermined noise level can not be reduced.

  The present bushless roller chain 5 has no bush which is press-fit to the inner link plate like the roller chain and the bush chain, so the insertion hole 16 of the inner link plate 17 may be inserted through the pin 12 Smaller diameter is sufficient. Therefore, it is possible to set a large dangerous cross section S = (Hd) · T directly related to the tensile strength of the chain. Here, H: width of the inner link plate 17 (see FIG. 3), d: thickness of the inner link plate 17 (see FIG. 2). As a result, the thickness T of the inner link plate 17 can be made equal to that of a conventional timing chain having a large pitch, and the mass per pitch can be reduced, and the thickness of the roller 13 is relatively large. It can be set, and the impact fatigue strength of the roller is also secured.

  In this bushless roller chain 5, the portion where the inner link 19 comes in sliding contact with the pin 12 is only the insertion hole 16 of the inner link plate 17, and the area is smaller than that of a chain having a conventional bush. For this reason, there is a possibility that chain elongation may occur due to wear of the pin during high-speed continuous operation of the chain, but in the present bushingless roller chain 5, the surface of the pin 12 is metal carbide such as chromium or vanadium or vanadium charcoal Since the nitrided hard layer is coated, wear due to the small area can be prevented.

  The present bushingless roller chain is suitable for use as a timing chain transmission device for a two-wheeled engine, but is not limited to this, and may be applied to a four-wheeled engine timing chain transmission, The present invention may be applied to other in-engine chain transmissions such as for driving a balancer, and for driving an oil pump, and is also applicable to other chain transmissions such as for industrial use.

  First, for comparison with the present bushless roller chain 5 shown in FIGS. 2 and 3, a bush chain and a silent chain which are conventionally used as a timing chain for a two-wheeled vehicle engine will be described. As shown in FIGS. 4A and 4B, the bush chain 30 has an outer link 35 in which both ends of a pair of outer link plates 31, 31 are connected by pins 32, 32, and a pair of inner link plates 37, 37 have inner links 39 connected by bushings 38, 38 at both ends, and pins 32 are penetrated through the bushings 38 and are alternately and endlessly connected with the outer links 35 and inner links 39 . The present bushing chain 30 is used for a timing chain transmission and transmits the rotation of a crank sprocket to a cam sprocket. At this time, the sprocket teeth mesh with the bushing 38 in a lubricating environment, and rotate relative to each other between the pin 32 and the bushing 38 for bending.

  As shown in FIGS. 5A and 5B, in the silent chain 40, the link plates 42 are alternately connected by the pins 41 so as to form an endless shape, and the guide link plates 43 are provided on the axially outermost side of these link plates 42. Is arranged. The pins 41 are fixed to the left and right guide link plates 43 by caulking or the like, and are slidably fitted in pin holes 45 formed at both ends of the link plate 42. The guide row G aligned with the guide link plate 43 in the width direction does not rotate relative to the pin 41 including the link plate 43, and the link plate 43 of the non-guide row N adjacent to the guide row G With relative rotation, the silent chain 40 can bend freely.

  The link plate 43 has a pair of teeth 46, 46 inside a line (pitch line) connecting the centers of the pair of left and right pin holes 45, and these teeth mesh with the sprocket teeth to transmit power. The guide link plate 43 contacts the tooth side of the sprocket to prevent the link plate 43 from coming off the sprocket. The crotch 47 is formed on the back surface of the guide link plate 43, and the guide link plate 43 is formed thinner than the plate thickness of the link plate 42, and the number of link plates is one more than that of the non-guide rows N Reduce uneven load blending due to

  In FIGS. 2 to 5, d is the outer diameter of the pin, E is the length of the pin, D is the outer diameter of the roller (FIGS. 2 and 3) or bush (FIG. 4) engaged with the sprocket, and P is the chain. The pitch, W, is the inner link plate meshing with the sprocket and the width dimension (FIGS. 2 and 4) or the width dimension of the link plate (FIG. 5).

  FIG. 6 is a diagram showing the main specifications and basic performance of the bushingless roller chain 5 according to the present invention shown in FIGS. 2 and 3, the conventional bushing chain 30 shown in FIG. 4 and the conventional silent chain 40 shown in FIG. It is. Each chain is used as a timing chain for a two-wheeled vehicle engine and has the same tensile strength and transmission torque capacity. The chain pitch P (4.76 mm) of the present bushingless roller chain 5 is set smaller than the chain pitch (6.35 mm) of the bush chain 30 and the chain pitch (6.35 mm) of the silent chain 40. This corresponds to the ratio of the pin outer diameter d to the chain pitch P [(d / P) = 0.42] and the ratio of the roller outer diameter D [(D In the state where the meshing with the sprocket teeth is appropriate, the dangerous cross-sectional area S is secured, and the roller thickness is large to secure the impact fatigue strength of the roller. It becomes possible by

  In addition, the mass w [0.153 (kg / m)] per meter of this bushless roller chain is bush chain [0.163 (kg / m)], silent chain [0.172 (kg / m)]. And the mass m per unit pitch decreases as the pitch P decreases, and the impact energy E described above is significantly smaller than the bush chain and the silent chain. FIG. 7 shows an example of the result of noise comparison test using a dedicated tester. The noise level I of the present bushingless roller chain 5 is smaller than that of the conventional bushing chain 30 and silent chain 40. In particular, the noise level is much smaller in the entire rpm range for the same meshing mechanism bushing chain and smaller in the high rpm range for the silent chain.

  Further, as shown in FIG. 8, the loss horsepower of the present bushingless roller chain 5 is smaller than that of the conventional bushing chain 30 and the timing system (transmission device) using the silent chain 40. The loss horsepower is significantly reduced, especially for silent chains, in all revolutions and also for bush chains, in high revolutions.

  The timing system using the present bushingless roller chain is as described above, as compared to the timing system using a bushing chain and a silent chain, which are applied to the timing chain transmission system of an engine for a two-wheeled vehicle. The noise level can be reduced to improve the quality of the two-wheeled vehicle, and the loss horsepower can be reduced to improve the fuel efficiency of the two-wheeled vehicle. The noise levels shown in FIGS. 6, 7 and 8 and the loss horsepower of the chain system, which are actual measurement examples by a dedicated test machine, have values close to theoretical calculation values. Further, the bushless roller chain of Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-44386) has substantially the same specifications as the bush chain and the basic performance is also substantially equal to the bush chain.

1 Timing chain drive 2 Crank sprocket 3 Cam sprocket 5 Bushless roller chain (timing chain)
6 tensioner 8 rotating body (sprocket)
9 Guide rotating body (roller)
11 outer link plate 12 pin 13 roller 15 outer link 16 insertion hole 17 inner link plate 19 inner link P chain pitch d pin outer diameter D roller outer diameter

Claims (5)

An outer link in which both ends of a pair of outer link plates are connected by pins and the rollers are rotatably supported by the pins;
An inner link comprising at least two inner link plates having insertion holes at both ends for rotatably inserting the pins;
A bushless roller in which the inner link plate is disposed between the outer link plate and the roller and the pin is inserted through the insertion hole to alternately connect the outer link and the inner link in an endless manner In the chain
Let P be the chain pitch, which is the distance between the centers of adjacent pairs of pins, d be the outer diameter of the pins, and D be the outer diameter of the rollers.
0.35P ≦ d ≦ 0.45P
0.60 P ≦ D ≦ 0.70 P,
A bushless roller chain characterized by The outer diameter d of the pin is 0.40P ≦ d ≦ 0.45P
The bushless roller chain according to claim 1. The chain pitch P is in the range of 4.0 to 5.0 [mm],
The bushless roller chain according to claim 1 or 2. The surface of the pin is coated with a hardened layer of metal carbide or vanadium carbonitride.
The bushless roller chain according to any one of claims 1 to 3. A crank sprocket connected to the engine crankshaft,
A cam sprocket connected to a camshaft of the engine;
The timing chain consisting of a bushingless roller chain according to any one of claims 1 to 4, wound between the crank sprocket and the cam sprocket.
A tensioner having a rotating body in rolling contact with the timing chain and biasing means for applying a biasing force to the rotating body;
A guide rotating body rotatably supported and rollingly contacting the timing chain to guide the timing chain;
Timing chain transmission with.

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