CN111594575A - A new type of silent chain and its assembly method - Google Patents

Abstract

The invention discloses a novel silent chain and an assembly method thereof, and the technical scheme is as follows: the chain consists of a working chain plate, a pin shaft connected with the working chain plate and a guide plate, wherein the pin shaft is inserted into the working chain plate and is in interference fit with the guide plate; the pretension force is 60-90% of the breaking load of the chain, and the pretension holding time is 0-120 seconds; the working chain plate can increase the contact area of the hinge and effectively reduce the contact stress of the hinge by reducing the fit clearance between the working chain plate and the pin shaft on the premise of not reducing the strength of the chain plate, thereby obtaining the best wear resistance. The design increases the oil storage space, promotes the production efficiency of silence chain, can effectively promote chain drive system's life.

Description

A new type of silent chain and its assembly method

technical field

The invention relates to the technical field of chains, in particular to a novel silent chain and an assembling method thereof.

Background technique

Silent chains are widely used in high-speed transmission engine timing systems such as automobiles and motorcycles. Compared with the roller chain, the silent chain has better NVH characteristics, which can effectively reduce the noise of the chain drive system and improve the sound quality. The silent chain consists of multiple identical guide plates, working chain plates and connecting pins. Because the traditional silent chain has certain limitations in the structural design, it will affect the wear resistance. As shown in Figure 1, the working chain plate of the traditional silent chain adopts the shaft hole clearance fit between the pin shaft and the working chain plate, the pin hole adopts a standard circular structure, and the circular shape of the pin shaft inserted into the pin hole of the chain plate The arc curvature radius is R1', and the arc curvature radius of the chain plate pin hole is R2'. In order to ensure that the pin shaft can be inserted into the chain plate pin hole loosely, the relational expression between R1' and R2' must be satisfied, R2'=R1 '+N', N'=0.02～0.04, although this can fundamentally solve the assembly quality and efficiency problems of the silent chain, the arc curvature center of the pin is the chain pitch center, and the arc curvature of the pin hole is The center and the pitch center of the chain are on the same line, and the gap between the pin shaft and the pin hole is large, which is bound to reduce the hinge contact area between the working chain plate and the pin shaft meshing transmission part, thereby reducing the wear resistance of the silent chain.

Due to the global energy saving and the improvement of environmental protection awareness, the lightening of automobiles has become a trend, and the engine is becoming more and more compact, so the engine timing chain is also required to be designed as small as possible, which greatly increases the difficulty of chain production and manufacturing. . The main dimension of the mute chain is called the pitch, and the commonly used mute chain specifications are:

Various models such as 6.35mm, 8mm and 9.525mm. The smaller the clearance between the pin and hole of the silent chain is, the higher the precision and the greater the difficulty in manufacturing. Dead Festival and other defective products. The existence of iron filings will compress the oil storage space of the pin hole, and even block the lubricating oil circulation system of the oil pump, which will seriously affect the normal operation of the engine, and eventually lead to a decrease in the service life of the engine.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides a novel silent chain and an assembling method thereof, which have good wear resistance, increase oil storage space, improve production efficiency, reduce manufacturing risks, and effectively increase service life.

In order to achieve the above object, the present invention is achieved through the following technical solutions: a new type of silent chain, which is composed of a plurality of working chain plates, a pin shaft connecting the working chain plates and a guide plate, the pin shafts are inserted into the working chain plates, and In interference fit with the guide plate, there is a lateral gap between the working chain plate and the guide plate. Meet the requirements of installation coordination and meshing transmission.

Preferably: the working chain plate is composed of a pair of pin holes, a pair of teeth and a tooth tip, the pin holes are formed by a plurality of arcs to form an irregular circular structure, and the pin shafts are inserted into the circular pin holes.

Preferably: the pin hole is composed of a certain length of meshing working arc AB, transition arc BC, transition arc CD, transition arc EF, transition arc FA and assembly oil storage arc DE. .

Preferably: the arc curvature centers O1, O1' of the pin shaft are the pitch centers of the chain, the center of curvature O2 of the meshing working arc AB segment of the pin hole, the curvature center O3 of the assembly oil storage arc segment DE and the chain link The distance from the center is on the same line.

Preferably, the radius of curvature R2 of the AB segment of the engaging working circular arc of the pin hole is greater than or equal to the radius of curvature R1 of the circular arc of the pin shaft inserted into the hole.

Preferably: the curvature radius R3 of the assembly oil storage arc DE section of the pin hole is greater than the curvature radius R2 of the meshing working arc AB section, so the relationship between R1, R2 and R3 is R3>R2≥R1, which can satisfy the The shaft can be easily inserted into the pin hole.

A new type of silent chain assembly method is characterized by the following steps:

S1. First assemble the working chain plate, the pin shaft and the guide plate connecting the working chain plate into a chain;

S2. Pre-tensioning is required, the pre-tensioning force is 60%-90% of the breaking load of the chain, and the pre-tensioning holding time is 0-120 seconds;

S3. After pre-pulling, the arc on one side of the pin shaft is closely attached to the side of the meshing arc AB section of the working chain plate, and the assembly oil storage arc DE and the arc on the other side of the pin shaft are formed. a gap.

Preferably: the size of the gap between the assembly oil storage arc DE and the arc on the other side of the pin shaft is 1% to 5% of the chain pitch, and the gap is filled with lubricating oil, which lays the foundation for the formation of the dynamic pressure oil film To meet the prerequisites, the pin shaft is always wrapped in the oil film and in contact with the pin hole of the working chain plate, increasing the oil storage space is conducive to improving the lubrication of the chain system, and the existence of the dynamic pressure oil film ensures that the silent chain is reduced during high-speed movement. Noise, and prolong the life of the silent chain system and engine.

The present invention has beneficial effects as follows:

The working chain plate can reduce the fitting gap between the working chain plate and the pin shaft, increase the hinge contact area, effectively reduce the hinge contact stress, and obtain the best wear resistance without reducing the strength of the chain plate. Design and assemble the oil storage arc DE section, which increases the oil storage space and improves the production efficiency of the silent chain, that is, the pin shaft can be easily inserted into the pin hole of the working chain plate, which fundamentally reduces the occurrence of incisions and holes in the manufacturing process. Risks such as tight joints, etc., the present invention can effectively improve the service life of the chain drive system.

Description of drawings

FIG. 1 is a view of a common conventional silent chain described in the background art when a chain plate and a pin are matched.

Fig. 2 is the front view of a kind of working chain plate in the present invention;

Fig. 3 is the schematic diagram of the present invention when the loose pin is inserted into the working chain plate;

Fig. 4 is a partial enlarged view in Fig. 3;

Fig. 5 is the matching view of the pre-stretched chain plate and the pin shaft in the present invention;

Figure 6 is an enlarged view of the pin hole in Figure 5;

Fig. 7 is the front view of the mute chain in the present invention;

Fig. 8 is the top view of the mute chain in the present invention;

Fig. 9 is a partial enlarged schematic view of the oil storage space in Fig. 8;

Figure 10 is the relationship between the pin hole fitting clearance and the hinge contact stress in the present invention;

Fig. 11 The comparative test results of the wear performance of the new silent chain in the present invention and the traditional silent chain.

Reference numerals: 1, silent chain; 2, working chain plate; 3, pin shaft; 4, guide plate; 21, pin hole; 22, tooth; 23, tooth top; 22a, inner surface; 22b, outer surface; 31, oil storage space.

Detailed ways

The preferred embodiments of the present invention will be further described in detail with reference to the accompanying drawings.

As shown in Figure 2-11, a new type of silent chain is composed of a plurality of working chain plates 2, pins 3 connecting the working chain plates 2, and a guide plate 4. The pin shafts 3 are inserted into the working chain plates 2, and are connected with the working chain plates 2. The guide plate 4 is in an interference fit, and there is a lateral gap between the working chain plate 2 and the guide plate 4 . Meet the requirements of installation coordination and meshing transmission. The working chain plate 2 is composed of a pair of pin holes 21, a pair of teeth 22 and a tooth top 23, the teeth are suspended downward in a triangle from the pin holes 21, and the teeth are formed by an inner side surface 22a and an outer side surface 22b, The pin hole 21 is composed of multiple arcs to form an irregular circular structure, and the pin shaft 3 is inserted into the circular pin hole 21 . The pin hole 21 is composed of a certain length of meshing working arc AB, transition arc BC, transition arc CD, transition arc EF, transition arc FA and assembly oil storage arc DE.

The arc curvature centers O1 and O1' of the pin shaft 3 are the pitch centers of the chain, and the center of curvature O2 of the meshing working arc AB section of the pin hole 21, the curvature center O3 of the assembly oil storage arc section DE and the chain pitch the centers are on the same line. The curvature radius R2 of the engaging working circular arc AB section of the pin hole 21 is close to or equal to the circular curvature radius R1 of the pin shaft 3 inserted into the hole. The curvature radius R3 of the assembly oil storage arc DE section of the pin hole 21 is greater than the curvature radius R2 of the meshing working arc AB section, so the relationship between R1, R2 and R3 is R3>R2≥R1, R2=R1+N , N=0～0.04, the pin shaft 3 can be easily inserted into the pin hole 21. This design can increase the contact area of the hinge and reduce the contact stress. When the tight edge tension of the chain is maintained at 2000N, when the matching gap between R1 and R2 changes, the hinge contact stress will change accordingly. When R2 is closer to R1 , the smaller the clearance fit between the two, the larger the contact area of the hinge, and the lower the contact stress, which is beneficial to fundamentally reduce the wear elongation of the silent chain, and greatly improve the wear resistance of the silent chain. Extend engine life.

In the present invention, the working chain plate 2 can increase the hinge contact area and effectively reduce the hinge contact stress by reducing the matching gap between the working chain plate 2 and the pin shaft 3 without reducing the strength of the chain plate, so as to obtain the best resistance. grinding performance. The oil storage arc DE section is designed and assembled to increase the oil storage space and improve the production efficiency of the silent chain, that is, the pin shaft 3 can be easily inserted into the pin hole 21 of the working chain plate 2, which fundamentally reduces the occurrence of manufacturing process. Risks such as cut holes and tight joints, the present invention can effectively improve the service life of the chain drive system.

A new type of silent chain assembly method, comprising the following steps:

S1. First assemble the working chain plate, the pin shaft and the guide plate connecting the working chain plate into a chain;

S2. Pre-tensioning is required, the pre-tensioning force is 60% of the breaking load of the chain, and the pre-tensioning holding time is 70 seconds;

S3. After pre-pulling, the arc on one side of the pin shaft is closely attached to the side of the meshing arc AB section of the working chain plate, and the assembly oil storage arc DE and the arc on the other side of the pin shaft are formed. For a gap, the gap between the assembly oil storage arc DE and the arc on the other side of the pin shaft is 1% to 5% of the chain pitch, the gap is represented by △2, and the oil storage space where this gap is located can be used In order to store enough lubricating oil, it lays a prerequisite for the formation of dynamic pressure oil film. The timing chain system of automobile engine belongs to a typical high-speed transmission, which requires continuous pressure oil injection lubrication. Small clearance flows, the pin shaft slides relatively in the pin hole of the working chain plate, in the present invention, the pin shaft is always wrapped in the oil film in contact with the pin hole of the working chain plate, increasing the oil storage space is conducive to improving the chain The lubrication of the system and the existence of the dynamic pressure oil film ensure that the silent chain reduces noise in high-speed motion, and prolongs the life of the silent chain system and engine.

In the present invention, the relationship between the Δ2 value and the P value needs to satisfy the following relationship: Δ2=(1%～5%)*P, for example, P=8mm, R1=1.66mm, R2=1.68mm; R3=1.85mm , after the chain plate and the pin are closely matched, the remaining gap △2=0.32mm, and the corresponding oil storage space area is 1.6mm ² . Referring to Fig. 1 of the prior art, the remaining gap Δ1 after the working chain plate is matched with the pin shaft is 0.06 mm, corresponding to an oil storage space area of 0.21 mm ² . Obviously, the oil storage space multiplied by the thickness of the chain plate is the oil storage space, and the oil storage capacity in the present invention is more than 7 times larger than that of the traditional silent chain.

As shown in Figure 7, Figure 8 and Figure 9, the position and flow direction of the lubricating oil in the silent chain can be seen. With the formation conditions of the dynamic pressure oil film, the lubricating oil can flow into the lateral gap between the guide plate and the working chain plate. Pin hole, the lateral clearance is represented by △H, the oil is stored in the gap between the pin shaft and the pin hole, and the △H value can be designed to be 0.4~0.8mm according to the needs of the manufacturing process. In this embodiment, the △H value is 0.5, K1 The lateral width of the end is 0.32mm, and the lateral width of the smallest end of K2 is 0.04mm. The pin shaft of the silent chain is driven by the load to drive the working chain plate to slide relatively, and the lubricating oil is squeezed, and continuously flows in from the large section K1 end of the wedge-shaped hole and flows out from the small section K2 end, which satisfies the formation conditions of the dynamic pressure oil film and is conducive to hinge friction. It can improve the lubrication effect, reduce friction loss, and finally improve the service life of the entire chain drive system.

Embodiment two,

In the present invention, the working chain plates shown in Fig. 3 are alternately inserted into the pins and assembled to form a new type of silent chain as shown in Fig. 7 and Fig. 8. Tension, after the pre-tension is maintained for 100 seconds, the chain is installed on the 19-tooth and 38-tooth matching sprockets, running at 6500 rpm, providing continuous pressure oil injection lubrication during the test, and the tension of the chain is tight during the test Always receive a load of 1000N, after running for a certain period of time, regularly measure the wear elongation (%) index of the chain. The mute chain of the same background technology is assembled by using the chain plate and the pin shaft as shown in Figure 1, and the same number of sections is assembled by the same method, and the comparison test is carried out on the same test bench.

As shown in the comparison test in FIG. 11 , a1, a2 and a3 are respectively a mute chain in the embodiment of the present invention, and b1 and b2 are a traditional mute chain for comparison. Among them, a1, a2 and a3 are three kinds of chains with clearance fit designed in the embodiment of the present invention, which are abbreviated as a1 chains: R2=R1+0.03, a2 chains: R2=R1+0.02. a3 chain: R2=R1+0.01. The R1 is the radius of curvature of the arc of the pin; R2 is the radius of curvature of the AB segment of the meshing working arc; and R3 is the radius of curvature of the DE segment of the assembly oil storage arc according to the embodiment of the present invention.

Among them, b1 and b2 are two traditional mute chains with different clearance fits implemented in comparison, b1 chain: R2'= R1'+0.03, b2 chain: R2'=R1'+0.02. The R1' is the arc curvature radius of the pin shaft; R2' is the arc curvature radius of the pin hole of the working chain plate. The test results show that, compared with the traditional silent chain, the present invention has a smaller wear elongation rate after running at a high speed for a certain period of time under the same fitting clearance condition. Similarly, in the case of reduced fit clearance, the smaller the wear elongation, the more wear-resistant the chain is. The comparative test results show that the invention can significantly improve the wear resistance of the silent chain.

Embodiment three,

The third embodiment is roughly the same as the first embodiment, the difference is that the pre-tensioning force is 90% of the chain breaking load, and the pre-tensioning holding time is 120 seconds.

The above embodiments are only used to illustrate the inventive concept of the present invention, but not to limit the protection of the rights of the present invention. Any non-substantial changes to the present invention by using this concept should fall within the protection scope of the present invention.

Claims (8)

1. The utility model provides a novel silence chain comprises the round pin axle and the baffle of work link joint, connection work link joint, its characterized in that: the pin shaft is inserted into the working chain plate and is in interference fit with the guide plate, and a lateral clearance is reserved between the working chain plate and the guide plate.

2. A novel silent chain as claimed in claim 1, wherein: the working chain plate consists of a pair of pin holes, a pair of teeth and a tooth top, the pin holes are of irregular circular structures formed by multiple sections of circular arcs, and the pin shafts are inserted into the circular pin holes.

3. A novel silent chain as claimed in claim 2, wherein: the pin hole is composed of an engaged working arc AB section, a transition arc BC section, a transition arc CD section, a transition arc EF section, a transition arc FA section and an assembly oil storage arc DE section which are of a certain length.

4. A novel silent chain as claimed in claim 3, wherein: the arc curvature centers O1 and O1' of the pin shaft are the pitch centers of the chain, and the curvature center O2 of the meshing working arc AB section and the curvature center O3 of the assembly oil storage arc DE section of the pin hole are on the same straight line with the pitch center of the chain.

5. A novel silent chain, according to claim 3 or 4, characterized in that: the radius of curvature R2 of the engagement working arc AB section of the pin hole is greater than or equal to the radius of curvature R1 of the arc of the pin inserted into the hole.

6. A novel silent chain as claimed in claim 5, wherein: the curvature radius R3 of the DE section of the oil storage arc for assembling the pin hole is larger than the curvature radius R2 of the AB section of the engaged working arc.

7. A novel silent chain assembling method is characterized by comprising the following steps:

s1, assembling the working chain plate 2, the pin shaft 3 connected with the working chain plate and the guide plate 4 into a chain;

s2, pre-tensioning is needed, the pre-tensioning force is 60% -90% of the broken load of the chain, and the pre-tensioning holding time is 0-120 seconds;

s3, after pre-tensioning, the arc at one side of the pin shaft 3 is tightly attached to the side of the engaging working arc AB section of the working chain plate 2, and a gap is formed between the assembling oil storage arc DE and the arc at the other side of the pin shaft.

8. The novel silent chain assembly method of claim 7, wherein: the size of a gap between the assembling oil storage arc DE and the arc on the other side of the pin shaft is 1% -5% of the chain pitch, and lubricating oil is filled in the gap.

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