Tensioner lever structure

Abstract

To provide a tensioner lever structure for enabling the rigidity to be secured even when there is no space on the back side of a slide surface while enabling weight saving.SOLUTION: A tensioner lever structure (TS) is provided. The tensioner lever structure (TS) includes a tensioner lever (10) which slides having a slide surface (10a) where a chain (CH) slides. The tensioner lever (10) has a wall part (11) erected from the slide surface (10a) in a height direction of the chain (CH). The wall part (11) has a high wall portion (11b) higher than a height (h) of the chain (CH), and a low wall portion (11a) lower than the height (h) of the chain (CH).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tensioner lever structure. [Background technology]

[0002] Conventionally, tensioner levers that press against a cam chain to apply an appropriate tension to the cam chain have been known (see, for example, Patent Document 1). In such tensioner levers, ensuring rigidity is sometimes important for purposes such as suppressing chain flutter and reducing noise. In the technology disclosed in Patent Document 1, the rigidity of the tensioner lever is ensured by providing an extended wall portion on the tensioner lever. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-186776 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described conventional technology, a wall portion is provided on the opposite side of the sliding surface on which the cam chain slides (i.e., the back side of the sliding surface). However, there are cases where it is difficult to provide a wall portion on the back side of the sliding surface due to factors such as the configuration of the engine.

[0005] Furthermore, in recent years, there has been a growing emphasis on ensuring that more people have access to affordable, reliable, sustainable, and advanced energy. From the perspective of contributing to energy efficiency, it is necessary not only to ensure the rigidity of the tensioner lever, but also to reduce its weight.

[0006] Therefore, an object of the present invention is to provide a tensioner lever structure that can ensure rigidity even when there is no space behind the sliding surface, and that can also be made lighter, thereby contributing to energy efficiency. [Means for solving the problem]

[0007] As a means for solving the above problem, a first aspect of the present invention is a tensioner lever structure (TS) comprising a tensioner lever (10) that oscillates and has a sliding surface (10a) on which a chain (CH) slides, wherein the tensioner lever (10) has a wall portion (11) that stands upright from the sliding surface (10a) in the height direction of the chain (CH), and the wall portion (11) has a high wall portion (11b) that is higher than the height (h) of the chain (CH) and a low wall portion (11a) that is lower than the height (h) of the chain (CH).

[0008] According to this configuration, a wall portion is provided on the chain side of the tensioner lever (sliding surface) to improve the rigidity of the tensioner lever. This ensures the rigidity of the tensioner lever even when there is no space to provide a wall portion behind the tensioner lever (sliding surface). Furthermore, by having a low wall portion and not making the entire wall portion a high wall portion, the weight of the tensioner lever can be reduced. Therefore, it is possible to provide a tensioner lever structure that ensures rigidity even when there is no space behind the tensioner lever and also allows for weight reduction. This in turn contributes to energy efficiency.

[0009] A second aspect of the present invention is characterized in that, in the first aspect, the tensioner lever (10) further has a pressure-receiving portion (12) that is pressed by a tensioner lifter (50), and the pressure-receiving portion (12) and the high wall portion (11b) are aligned in the pressing direction in which the tensioner lifter (50) presses the pressure-receiving portion (12).

[0010] This configuration improves the rigidity of the portion of the tensioner lever that is pressed by the tensioner lifter.

[0011] A third aspect of the present invention is characterized in that, in the second aspect, the tensioner further includes a pivot shaft (20) that pivotally supports the tensioner lever (10), and a boundary portion (11c) located at the boundary between the high wall portion (11b) and the low wall portion (11a) is located between the pivot shaft (20) and the pressure-receiving portion (12).

[0012] With this configuration, the low wall portion is located on the pivot shaft side and the high wall portion is located on the pressure-receiving portion side. This allows the high wall portion to be provided in areas where rigidity is required, while the low wall portion is used in areas where rigidity is not required, thereby more reliably ensuring the rigidity of the tensioner lever as a whole and reducing its weight.

[0013] A fourth aspect of the present invention is characterized in that, in the third aspect, the boundary portion (11c) has an inclined portion (11d) whose height gradually increases from the low wall portion (11a) to the high wall portion (11b).

[0014] This configuration makes it possible to avoid a sudden change in rigidity at the boundary between the low wall portion and the high wall portion.

[0015] A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the height (H) of the high wall portion (11b) is 1.2 to 1.8 times the height (h) of the chain (CH).

[0016] This configuration makes it possible to more effectively achieve both rigidity and weight reduction.

[0017] A sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the tensioner lever (10) has a back wall portion (13) extending on the opposite side of the chain (CH) as viewed from the sliding surface (10a), the back wall portion (13) has a high-wall-side back wall portion (13b) aligned with the high wall portion (11b) in the height direction, and a low-wall-side back wall portion (13a) aligned with the low wall portion (11a) in the height direction, and a lightening portion (14) is formed in the low-wall-side back wall portion 13a.

[0018] With this configuration, the weight of the tensioner lever can be further reduced by the lightening portion. Furthermore, by providing the lightening portion on the bottom wall side, it becomes easier to ensure the necessary rigidity of the tensioner lever. In other words, it is possible to more effectively achieve both ensuring rigidity and reducing weight. [Effects of the Invention]

[0019] According to the above aspects of the present invention, it is possible to provide a tensioner lever structure that can ensure rigidity even when there is no space behind the sliding surface and that can also be made lighter, thereby contributing to improved energy efficiency. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a right side view of a motorcycle according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view showing an engine of the motorcycle. [Figure 3] FIG. 2 is an enlarged view showing the tensioner lever structure according to the embodiment of the present invention. [Figure 4] FIG. 4 is a view showing the tensioner lever of FIG. 3. [Figure 5] 5 is a view of the tensioner lever of FIG. 4 as seen from the arrow V. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, directions such as front, rear, left, and right are the same as directions in the vehicle described below unless otherwise specified. In addition, an arrow FR indicating the front of the vehicle and an arrow UP indicating the top of the vehicle are shown in appropriate places in the drawings used in the following description.

[0022] <Entire vehicle> 1 is a right side view of a motorcycle 100, which is an example of a saddle-ride type vehicle. The motorcycle 100 of this embodiment is equipped with a front wheel 2 which is a steered wheel, a rear wheel 3 which is a drive wheel, a front fork 4 which supports the front wheel 2, a swing arm (not shown) which supports the rear wheel 3, a body frame 5 which supports the front fork 4 and the swing arm, and an engine (internal combustion engine, prime mover) 1 supported by the body frame 5.

[0023] A pair of front forks 4 are provided on the left and right. The front forks 4 are linked to a steering handle (bar handle) 6 extending in the left-right direction (vehicle width direction) via, for example, a steering system (not shown). A seat 7 on which a rider of the motorcycle 100 sits is provided behind the steering handle 6.

[0024] 2 is an enlarged view showing a schematic configuration of the engine 1 according to this embodiment. A crankshaft 31 having a rotation axis (crank axis) C1 aligned in the left-right direction is disposed within a crankcase 30 of the engine 1. A cylinder 40 is erected on the crankcase 30 and faces diagonally upward and forward.

[0025] A piston (not shown) is provided in the cylinder 40. Reciprocating motion of the piston is converted into rotational motion of the crankshaft 31 via, for example, a connecting rod (not shown). A first camshaft 41 and a second camshaft 42 having rotation axes parallel to the crank axis C1 are disposed in a cylinder head 40a attached to the top of the cylinder 40. The first camshaft 41 is located on the front side of the top of the cylinder 40. The second camshaft 42 is located on the rear side of the top of the cylinder 40. A cylinder head cover 40b may be attached to the top of the cylinder head 40a.

[0026] A cam chain chamber 43 is provided, for example, on a side of the cylinder 40, to house a cam chain (chain) CH that links the crankshaft 31 with the camshafts 41 and 42. The cam chain CH is an endless component. The cam chain CH is wound around the cam drive sprocket 31a of the crankshaft 31, the cam driven sprocket 41a of the first camshaft 41, and the cam driven sprocket 42a of the second camshaft 42. Note that arrow F1 in the figure indicates the rotation direction of the cam drive sprocket 31a (crankshaft 31) when the engine is running. Similarly, arrows F2 and F3 indicate the rotation directions of the cam driven sprockets 41a and 42a (camshafts 41 and 42), respectively.

[0027] The portion of the cam chain CH located in front of the cylinder 40 is pulled in and tensioned by the cam drive sprocket 31a, i.e., the tight side. On the other hand, the portion of the cam chain CH located behind the cylinder 40 is fed out and slackened by the cam drive sprocket 31a, i.e., the slack side. Note that the portion of the cam chain CH located above the cylinder 40 (the portion spanning the cam driven sprockets 41a, 42a) may also be considered part of the tension side of the cam chain CH. The cam chain CH winds around the outer peripheries of the sprockets 31a, 41a, 42a along a plane perpendicular to the left-right direction.

[0028] A chain guide 44 is provided in the front portion of the cam chain chamber 43. The chain guide 44 makes sliding contact with the tension side of the cam chain CH from outside (the front side) of the winding area of ​​the cam chain CH, and guides the cam chain CH in the traveling direction. Note that a similar chain guide may be provided in the upper portion of the cam chain chamber 43, making sliding contact with the tension side of the cam chain CH from outside (the upper side) of the winding area of ​​the cam chain CH, and guiding the cam chain CH in the traveling direction.

[0029] Meanwhile, a tensioner lever structure TS equipped with a tensioner lever 10 is provided at the rear of the cam chain chamber 43. The tensioner lever 10 slides against the slack side of the cam chain CH from the outside (rear side) of the winding area of ​​the cam chain CH, guiding the cam chain CH in the direction of travel. The tensioner lever 10 also applies an appropriate tension to the slack side of the cam chain CH to remove slack from the cam chain CH. The tensioner lever structure TS will be described in detail below.

[0030] <Tensioner lever structure> Figure 3 is an enlarged view showing the tensioner lever structure TS of this embodiment. As shown in Figures 2 and 3, the tensioner lever structure TS of this embodiment includes a tensioner lever 10, a pivot shaft 20 connected to a member 21 and extending in the left-right direction, and a tensioner lifter 50. The tensioner lever 10 extends along the longitudinal direction (travel direction) of the cam chain CH. The pivot shaft 20 supports one end of the tensioner lever 10 (the lower end in the example of Figure 2). This allows the pivot shaft 20 to support the tensioner lever 10 so that it can swing. The tensioner lifter 50 has a plunger 51 that presses the tensioner lever 10 toward the cam chain CH.

[0031] The tensioner lever 10 is made of, for example, a resin material. The tensioner lever 10 has a sliding surface (sliding contact surface) 10a along which the cam chain CH slides (comes into sliding contact). The sliding surface 10a is pressed against the cam chain CH by the pressing force exerted by the tensioner lifter 50 (plunger 51). The sliding surface 10a extends along the longitudinal direction of the cam chain CH. In the illustrated example, the sliding surface 10a is gently curved so as to be convex toward the inside of the winding area of ​​the cam chain CH when viewed from the left and right (as viewed from the side of the engine). The tensioner lever 10 may be made of a material having elasticity, such as steel, or a hybrid material of metal and resin.

[0032] Hereinafter, the direction along the sliding surface 10a (i.e., the longitudinal direction or traveling direction of the cam chain CH) will be referred to as the sliding direction. The height direction of the cam chain CH sliding on the sliding surface 10a will be simply referred to as the height direction. The height direction is also the direction perpendicular to the sliding surface 10a (i.e., the direction of the intersection of the sliding surface 10a). Hereinafter, the dimension in the height direction will be simply referred to as the height. Furthermore, the sliding surface 10a side of the tensioner lever 10 will be referred to as the "front side of the tensioner lever 10 (sliding surface 10a)" or the "chain side of the tensioner lever 10 (sliding surface 10a)," and the opposite side will be referred to as the "back side of the tensioner lever 10 (sliding surface 10a)."

[0033] Figures 4 and 5 are views showing the tensioner lever 10 extracted from Figure 3. As shown in Figures 3 and 4, the tensioner lever 10 in this embodiment has a wall portion 11, a pressure-receiving portion 12, and a back wall portion 13.

[0034] The wall portion 11 stands upright from the sliding surface 10a in the height direction of the cam chain CH. In other words, the wall portion 11 is provided on the chain side of the tensioner lever 10 (sliding surface 10a). The wall portion 11 extends in the sliding direction. The wall portion 11 is a portion for increasing the rigidity of the tensioner lever 10. As shown in FIG. 5, the tensioner lever 10 in this embodiment has two wall portions 11. The two wall portions 11 stand upright from both side edges of the sliding surface 10a. The cam chain CH slides between the two wall portions 11 on the sliding surface 10a.

[0035] 3 and 4, the wall portion 11 has a high wall portion 11b that is higher than the height h of the cam chain CH, a low wall portion 11a that is lower than the height h of the cam chain CH, and a boundary portion 11c. The height H of the high wall portion 11b is preferably, for example, 1.2 to 1.8 times the height h of the cam chain CH.

[0036] The boundary portion 11c is located at the boundary between the low wall portion 11a and the high wall portion 11b. The low wall portion 11a, boundary portion 11c, and high wall portion 11b are arranged in this order in the sliding direction. In the illustrated example, the boundary portion 11c has an inclined portion 11d whose height gradually increases from the low wall portion 11a to the high wall portion 11b. In other words, the height of the wall portion 11 changes smoothly from the low wall portion 11a to the high wall portion 11b. The tip surface of the inclined portion 11d in the height direction is inclined with respect to the intersecting direction of the sliding surface 10a. In other words, the boundary portion 11c in the illustrated example is not perpendicular to the sliding surface 10a.

[0037] The pressure-receiving portion 12 is a portion that is pressed by the tensioner lifter 50 (plunger 51). The pressure-receiving portion 12 and the high wall portion 11b are aligned in the pressing direction in which the tensioner lifter 50 (plunger 51) presses the pressure-receiving portion 12. In other words, the high wall portion 11b of the wall portion 11 is located on the axis C2 of the plunger 51.

[0038] The aforementioned boundary portion 11c is located between the pivot shaft 20 and the pressure-receiving portion 12 (tensioner lifter 50) in the sliding direction. That is, in the sliding direction, the low wall portion 11a is located on the pivot shaft 20 side, and the high wall portion 11b is located on the pressure-receiving portion 12 side. More specifically, in the illustrated example, the boundary portion 11c is located near a midpoint M in the sliding direction between the pivot shaft 20 and the pressure-receiving portion 12. The term "midpoint M" refers to a point that is equidistant d from both the pivot shaft 20 and the pressure-receiving portion 12.

[0039] The back wall portion 13 extends on the opposite side of the cam chain CH from the sliding surface 10a. In other words, the back wall portion 13 is provided on the back side of the tensioner lever 10 (sliding surface 10a). The back wall portion 13 extends in the sliding direction. As shown in FIGS. 3 and 4, the back wall portion 13 has a high-wall-side back wall portion 13b aligned with the high wall portion 11b in the height direction, and a low-wall-side back wall portion 13a aligned with the low wall portion 11a in the height direction. The maximum height of the high wall portion 11b (the maximum value of the height of the high wall portion 11b) is greater than the maximum height of the low wall portion 11a (the maximum value of the height of the low wall portion 11a).

[0040] The low-side rear wall portion 13a is formed with a plurality of lightening holes (lightening portions) 14. In the illustrated example, the high-side rear wall portion 13b is also formed with a plurality of lightening holes 14. The total area of ​​the lightening holes 14 formed in the low-side rear wall portion 13a may be larger than the total area of ​​the lightening holes 14 formed in the high-side back wall portion 13b.

[0041] Next, the operation of the tensioner lever structure TS configured as above will be described.

[0042] In conventional technology, in order to ensure the rigidity of the tensioner lever, a wall portion is provided on the side opposite the cam chain as viewed from the sliding surface on which the cam chain slides (i.e., the back side of the sliding surface). However, there are cases where it is difficult to provide a wall portion on the back side of the sliding surface due to factors such as the engine configuration. Furthermore, from the perspective of contributing to energy efficiency, it is necessary not only to ensure the rigidity of the tensioner lever but also to achieve a lightweight tensioner lever.

[0043] To address this issue, the tensioner lever structure TS of this embodiment is provided with a wall portion 11 on the chain side of the tensioner lever 10 (sliding surface 10a) to improve the rigidity of the tensioner lever 10. This ensures the rigidity of the tensioner lever 10 even if there is no space to provide the wall portion 11 on the back side of the tensioner lever 10 (sliding surface 10a). Also, by having the wall portion 11 with the low wall portion 11a and not making the entire wall portion 11 the high wall portion 11b, the weight of the tensioner lever 10 can be reduced.

[0044] As described above, the tensioner lever structure TS in the above embodiment is a tensioner lever structure comprising a tensioner lever 10 that swings and has a sliding surface 10a along which a chain (cam chain CH) slides, and the tensioner lever 10 has a wall portion 11 that stands upright from the sliding surface 10a in the height direction of the cam chain CH, and the wall portion 11 has a high wall portion 11b that is higher than the height h of the cam chain CH and a low wall portion 11a that is lower than the height h of the cam chain CH.

[0045] This configuration makes it possible to provide a tensioner lever structure TS that can ensure rigidity even when there is no space behind the tensioner lever 10 and also allows for weight reduction, which in turn contributes to energy efficiency.

[0046] In the above-mentioned tensioner lever structure TS, the tensioner lever 10 further has a pressure-receiving portion 12 that is pressed by a tensioner lifter 50, and is characterized in that the pressure-receiving portion 12 and the high wall portion 11b are aligned in the pressing direction in which the tensioner lifter 50 presses the pressure-receiving portion 12.

[0047] This configuration can improve the rigidity of the portion of the tensioner lever 10 that is pressed by the tensioner lifter 50 (that is, the periphery of the pressure-receiving portion 12).

[0048] The tensioner lever structure TS further includes a pivot shaft 20 that supports the tensioner lever 10 so that the tensioner lever 10 can swing, and a boundary portion 11c located at the boundary between the high wall portion 11b and the low wall portion 11a is located between the pivot shaft 20 and the pressure-receiving portion 12.

[0049] As a result of careful consideration, the inventors of the present application have found that the area of ​​the tensioner lever 10 that requires particular rigidity is the area around the pressure receiving portion 12, and that there is no need to increase the rigidity excessively around the pivot shaft 20. With the above configuration, the low wall portion 11a is located on the pivot shaft 20 side, and the high wall portion 11b is located on the pressure receiving portion 12 side. By providing the high wall portion 11b in the area that requires rigidity and using the low wall portion 11a in the area that does not require rigidity, it is possible to more reliably ensure the rigidity of the tensioner lever 10 as a whole and reduce its weight.

[0050] In the tensioner lever structure TS, the boundary portion 11c is characterized by having an inclined portion 11d whose height gradually increases from the low wall portion 11a toward the high wall portion 11b.

[0051] This configuration makes it possible to avoid a sudden change in rigidity at the boundary between the low wall portion 11a and the high wall portion 11b.

[0052] In the above tensioner lever structure TS, the height H of the high wall portion 11b is 1.2 to 1.8 times the height h of the cam chain CH.

[0053] This configuration makes it possible to more effectively achieve both ensuring rigidity and reducing weight.

[0054] In the above-mentioned tensioner lever structure TS, the tensioner lever 10 has a back wall portion 13 extending on the opposite side of the cam chain CH when viewed from the sliding surface 10a, and the back wall portion 13 has a high-wall side back wall portion 13b aligned with the high-wall portion 11b in the height direction, and a low-wall side back wall portion 13a aligned with the low-wall portion 11a in the height direction, and a lightening portion (lightening hole 14) is formed in the low-wall side back wall portion 13a.

[0055] According to this configuration, the weight of the tensioner lever 10 can be further reduced by the weight reduction holes 14. Furthermore, by providing the weight reduction holes 14 on the bottom wall portion 11a side (i.e., the pivot shaft 20 side), it becomes easier to ensure the necessary rigidity of the tensioner lever 10. In other words, it is possible to more effectively achieve both ensuring rigidity and reducing the weight.

[0056] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0057] For example, the tensioner lever structure of this embodiment may be applied to saddle-ride type vehicles other than motorcycles.

[0058] The saddle-ride type vehicle includes all vehicles on which a driver straddles the body, including not only motorcycles (including motorized bicycles and scooter-type vehicles), but also three-wheeled vehicles (including vehicles with one front wheel and two rear wheels, as well as vehicles with two front wheels and one rear wheel) or four-wheeled vehicles (such as four-wheeled buggies). It may also be applied to vehicles that include an electric motor as a prime mover. It may also be applied to vehicles other than saddle-ride type vehicles (such as passenger cars, buses, and trucks).

[0059] The configurations in the above-described embodiments are merely examples of the present invention, and various modifications are possible without departing from the spirit of the present invention, such as replacing components of the embodiments with well-known components. Furthermore, the above-described embodiments and modifications may be combined as appropriate. [Explanation of symbols]

[0060] TS tensioner lever structure CH cam chain (chain) 10 Tensioner lever 10a Sliding surface 11 Wall 11a Low wall section 11b High wall section 11c Boundary 11d Slope 12 Pressure receiving part 13 Back wall 13a Lower wall back wall 13b High wall side rear wall 14 Lightening hole (lightening part) 20 pivot axis 50 Tensioner lifter

Claims

1. a tensioner lever having a sliding surface on which the chain slides, which swings to slide against the slack side of the cam chain from outside the winding area of ​​the cam chain, and which guides the advancing direction of the cam chain; a pivot shaft that supports the tensioner lever so that the tensioner lever can swing and is provided in a crankcase, The tensioner lever has wall portions erected in the height direction of the chain from both side edges of the sliding surface, and a pressure-receiving portion pressed by a tensioner lifter provided on a side surface of the cylinder, The wall portion has a high wall portion that is 1.2 to 1.8 times higher than the height of the chain, a low wall portion that is lower than the height of the chain, and an inclined portion that is located at the boundary between the high wall portion and the low wall portion and whose height gradually increases from the low wall portion toward the high wall portion, the low wall portion, the inclined portion, and the high wall portion are arranged in this order from one end of the tensioner lever in the sliding direction of the cam chain, and the high wall portion extends to the other end of the tensioner lever, the inclined portion is located near a midpoint equidistant from the pivot shaft and the pressure-receiving portion, A tensioner lever structure, characterized in that the low wall portion is located on the pivot shaft side and the high wall portion is located on the pressure receiving portion side with respect to the intermediate point.

2. 2. The tensioner lever structure according to claim 1, wherein the pressure receiving portion and the high wall portion are aligned in a pressing direction in which the tensioner lifter presses the pressure receiving portion.

3. the tensioner lever has a back wall portion extending on the opposite side of the chain from the sliding surface, The rear wall portion has a high-wall-side rear wall portion aligned with the high wall portion in the height direction and a low-wall-side rear wall portion aligned with the low wall portion in the height direction, 3. The tensioner lever structure according to claim 1, wherein a lightening portion is formed in the lower wall side rear wall portion.

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