JP2008223915A - Bearing device and engine equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device capable of preventing the occurrence of noise from a bearing and suppressing fretting wear, and an engine equipped with the bearing device. <P>SOLUTION: This bearing device is equipped with the bearing 46 having a plurality of rolling elements 46c interposed between an inner ring 46a and an outer ring 46b, a rotary shaft (crankshaft) 23 fitted to the inner ring 46a of the bearing 46, a case member (unit case) 43 fitted to the outer ring 46b of the bearing 46, and an oil supplying mechanism (lubricating oil supplying device) 60 for supplying lubricating oil to an inner ring fitting part A of the crankshaft 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing device that includes a rotating shaft that fits into an inner ring of a bearing, and a case member that fits to an outer ring of the bearing, and an engine that includes the bearing device.

For example, in a single cylinder engine, a crankcase may be divided into left and right in the direction of the crankshaft around the cylinder axis, and the crankshaft may be supported by the left and right case portions with a bearing interposed therebetween.

This type of bearing generally has a structure in which a large number of rolling elements such as balls and rollers are interposed between an inner ring and an outer ring. A structure is adopted in which the left and right case portions are fitted to the outer ring of the bearing, the crank journal portion of the crankshaft is fitted to the left and right inner rings, and lubricating oil is supplied to the rolling elements of the bearing. (For example, refer to Patent Document 1).
Japanese Patent No. 3139219

  By the way, in the case where the crankshaft is supported by the left and right case portions via bearings, fretting wear (tapping and wear) is likely to occur in the crank journal portion of the crankshaft, and the progress of the wear increases. Has a problem that abnormal noise occurs.

  Such fretting wear is considered to be caused by the following reasons. In the case of the structure in which the crankcase is divided into the left and right case portions, there is a limit to the accuracy of the left and right case fitting portions of the left and right case portions, so that the shaft core is slightly shifted. In this case, if the left and right bearings are press-fitted into the left and right case portions and the crankshaft with a high degree of fitting, noise due to squeezing or the like tends to occur from the bearings. In order to avoid the generation of such noise, the deviation of the shaft core is absorbed by reducing the degree of fitting of any one of the bearings. Specifically, one of the left and right bearings is firmly press-fitted to the crankshaft by an interference fit, and the other bearing is supported by an interference fit or an intermediate fit with a smaller degree of fitting than the one bearing.

  There may be a slight gap between the inner ring and the crankshaft of the bearing that is fixedly fitted in this way or the intermediate fit due to its dimensional tolerance, and this gap may cause fretting wear. Conceivable.

  The present invention has been made in view of the above-described conventional situation, and it is an object of the present invention to provide a bearing device capable of suppressing fretting wear while preventing noise from being generated from the bearing, and an engine including the bearing device. It is said.

  The present invention provides a bearing device including a bearing in which a large number of rolling elements are interposed between an inner ring and an outer ring, a rotating shaft that is fitted to the inner ring of the bearing, and a case member that is fitted to the outer ring of the bearing. An oil supply mechanism that supplies lubricating oil to at least one of an inner ring fitting portion between the inner ring and the rotating shaft or an outer ring fitting portion between the outer ring and the case member is provided.

  According to the bearing device of the present invention, since the lubricating oil is supplied to at least one of the inner ring fitting portion of the rotating shaft or the outer ring fitting portion of the case member, the lubricating oil is slightly in the inner ring or the outer ring fitting portion. Therefore, it is possible to suppress the occurrence of fretting wear on the rotating shaft due to the force perpendicular to the rotating shaft. As a result, the degree of fitting of the bearing with the rotating shaft or the case member can be reduced, noise can be prevented from being generated from the bearing, and assembly can be easily performed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIGS. 1 to 9 are views for explaining a bearing device and an engine equipped with the bearing device according to an embodiment of the present invention. In the present embodiment, an engine bearing device mounted on a motorcycle will be described as an example. In the description of the present embodiment, the terms front and rear and left and right mean front and rear and left and right when viewed in a seated state.

  In the figure, reference numeral 1 denotes an off-road type motorcycle. The motorcycle 1 swings up and down by a body frame 2, a front fork 4 supported by a head pipe 3 disposed at the front end of the body frame 2 so as to be steerable left and right, and a rear end of the body frame 2. And a rear arm 5 that is movably supported.

  A front wheel 6 is pivotally supported at the lower end of the front fork 4, and a steering handle 7 is fixed to the upper end. A rear wheel 8 is pivotally supported at the rear end portion of the rear arm 5, and a rear cushion 9 is interposed between the rear arm 5 and the vehicle body frame 2. A fuel tank 10 and a saddle type seat 11 are mounted on the vehicle body frame 2.

  The vehicle body frame 2 includes a cradle-shaped main frame 2c composed of a down tube 2a and an upper tube 2b, and a seat rail 2d extending obliquely upward rearward from the rear end portion of the main frame 2c.

  An engine 15 is mounted in the cradle of the main frame 2c, and the engine 15 is suspended and supported by the main frame 2c.

  The engine 15 is a water-cooled four-cycle single-cylinder engine, and a cylinder block 17, a cylinder head 18, and a head cover 19 are sequentially stacked on an upper joint surface of a crankcase (case member) 16, and these are stacked by a plurality of bolts 20. It has a combined structure.

  A transmission case (case member) 22 is integrally formed on the rear side of the crankcase 16, and an oil reservoir 16 a is formed at the bottom of the crankcase 16.

  A crankshaft (rotary shaft) 23 is accommodated in the crankcase 16 in the vehicle width direction. Crank pins 25 are attached to the left and right crank arms 23a, 23a of the crankshaft 23. A large end 24 a of a connecting rod 24 is connected to the crank pin 25 with a bearing 28 interposed therebetween, and a small end 24 b of the connecting rod 24 is slidably inserted into the cylinder bore of the cylinder block 17. Connected to a piston (not shown).

  In the cam chamber 26 formed by the cylinder head 18 and the head cover 19, intake and exhaust cam shafts 27 and 27 are arranged in parallel with the crankshaft 23. (Shown) is driven to open and close.

  A transmission 30 is accommodated in the transmission case 22. The transmission 30 includes a main shaft (transmission shaft) 32 to which an input gear group 31 is attached, a drive shaft (transmission shaft) 34 to which an output gear group 33 meshing with the input gear group 31 is attached, and the main shaft. And a clutch mechanism 35 attached to the right end portion of the shaft 32. The main shaft 32 and the drive shaft 34 are arranged in parallel with the crankshaft 23.

  A left end 34c of the drive shaft 34 protrudes outward from the transmission case 22, and a drive sprocket 36 attached to the left end 34c is connected to the rear wheel sprocket 38 of the rear wheel 8 via a chain 37. Has been.

  The clutch mechanism 35 has a structure in which a plurality of clutch plates 35 c are interposed between an outer drum 35 a rotatably attached to the main shaft 32 and an inner drum 35 b splined to the main shaft 32. A large reduction gear 40 fixed to the outer drum 35 a is rotatably mounted on the main shaft 32, and a small reduction gear 29 key-fitted to the crankshaft 23 is attached to the reduction large gear 40. Meshed.

  The clutch mechanism 35 connects or blocks transmission of engine power from the crankshaft 23 to the main shaft 32 by advancing and retracting a bush rod 39 inserted into the axis of the main shaft 32.

  The engine 15 includes a lubricating oil supply device 60 that supplies the lubricating oil in the oil reservoir 16a of the crankcase 16 to each portion to be lubricated.

  As shown mainly in FIG. 9, the lubricating oil supply device 60 includes a strainer 61 that opens to the oil reservoir 16 a, an oil supply pump 62 that is connected to the strainer 61, and lubricating oil that is sucked by the oil supply pump 62. An oil cleaner 63 for filtering, a crankshaft path 64 that guides lubricating oil from the oil cleaner 63 to the crankshaft 23, a transmission path 65 that leads to the transmission 30, and a camshaft path 66 that leads to the intake and exhaust camshafts 27. Have.

  The oil pump 62 is disposed in the transmission case 22 and rotates a pump gear 62a through an intermediate gear 68 by a pump drive gear 67 mounted on the main shaft 32 so as to rotate together with the large reduction gear 40. Driven (see FIGS. 3 and 5).

  The oil cleaner 63 is detachably disposed in the clutch cover 70 mounted on the right side wall of the crankcase 16 and the transmission case 22 (see FIG. 4).

  The crankshaft path 64 includes a piston cooling path 64a that ejects lubricating oil from the oil cleaner 63 toward the back surface of the piston, and a crankshaft passage 23d formed in the shaft core of the crankshaft 23 to a shaft hole of the crankpin 25. And a crank pin path 64b for supplying the bearing 28 through 25a.

  The transmission path 65 includes a transmission path 65a connected to the piston cooling path 64a, and a plurality of branch paths from the main shaft path 32a formed in the axial center of the main shaft 32 with lubricating oil from the transmission path 65a. A main shaft path 65b that supplies the input gear 31a supported by the main shaft 32 via the main shaft 32b and a part of the lubricating oil from the transmission pipe 69 that is branched and connected to the transmission path 65a are input gear group 31, The mission shower path 65c ejected to the meshing portion of the output gear group 33 and the remaining portion of the lubricating oil from the transmission pipe 69 are driven through a plurality of branch paths 34b from a drive path 34a formed in the axis of the drive shaft 34. And a drive shaft path 65d that supplies each output gear 33a supported by the shaft 24.

  The camshaft path 66 supplies lubricating oil from the camshaft path 66a connected to the transmission path 65a to the intake and exhaust camshafts 27 and 27 via the hydraulic tensioner 66b. Thus, the lubricating oil supplied to each lubricated portion is returned to the oil reservoir 16a.

  The crankshaft 23, the main shaft 32, and the drive shaft 34 are supported by the crankcase 16 and the transmission case 22 through a bearing device 41, and have the following structure in detail.

  The crankcase 16 and the transmission case 22 are divided into left and right unit cases 43 and 44 in the crankshaft direction around the cylinder axis a.

  The crankshaft 23 is rotatably supported by left and right bearings 45 and 46 by annular boss portions 43a and 44a formed in the left and right unit cases 43 and 44, respectively.

  The left and right bearings 45, 46 have a structure in which a large number of spherical rolling elements 45c, 46c are interposed between inner rings 45a, 46a and outer rings 45b, 46b, respectively.

  The left and right inner rings 45a and 46a are fitted with crank journal portions 23b and 23b formed on the outer sides in the axial direction of the left and right crank arms 23a of the crankshaft 23, and the left and right outer rings. The boss portions 43a, 44a of the left and right unit cases 43, 44 are fitted to 45b, 46b with fitting members 52, 52 interposed therebetween.

  Here, the degree of fitting of the right bearing 46 to the crankshaft 23 is smaller than the degree of fitting of the left bearing 45 to the crankshaft 23. The degree of fitting of the left bearing 45 to the crankshaft 23 is equivalent to the degree of fitting of the left and right bearings 45, 46 to the unit cases 43, 44.

  Specifically, the outer rings 45b and 46b of the left and right bearings 45 and 46 are firmly press-fitted into the left and right boss portions 43a and 44a by an interference fit.

  The inner ring 45a of the left bearing 45 is firmly pressed into the left crank journal portion 23b of the crankshaft 23 by an interference fit.

  The inner ring 46a of the right bearing 46 is fitted and supported on the right crank journal portion 23b of the crankshaft 23 by a stop fit or an intermediate fit.

  The main shaft 32 and the drive shaft 34 are connected to the left and right bearings 47, 49 and 48, 50 by left and right annular bosses 43b, 43c and 44b, 44c formed in the left and right unit cases 43 and 44, respectively. It is supported so that it can rotate freely. The bearings 47 to 50 have the same structure as the bearings 45 and 46.

  The main shaft 32 is fitted to the inner rings 47a and 48a of the left and right bearings 47 and 48, and the left and right boss portions 43b and 44b are fitted to the left and right outer rings 47b and 48b. . The degree of fitting of the right bearing 48 to the main shaft 32 is smaller than the degree of fitting of the left bearing 47 to the main shaft 32.

  The drive shaft 34 is fitted to the inner rings 49a and 50a of the left and right bearings 49 and 50, and the left and right boss portions 43c and 44c are fitted to the left and right outer rings 49b and 50b. . The degree of fitting of the left bearing 49 to the drive shaft 34 is smaller than the degree of fitting of the right bearing 50 to the drive shaft 34.

  The bearing device 41 includes an oil supply mechanism (lubricating oil supply device) 60 that supplies lubricating oil to the inner ring fitting portions A, B, and C of the bearings 46, 48, and 49 on the side with a small fitting degree.

  The oil supply mechanism 60 includes a first oil supply passage 23e that supplies the lubricating oil sucked by the oil supply pump 62 and filtered by the oil cleaner 63 to the inner ring fitting portion A of the bearing 46 of the crankshaft 23, and the above-described oil supply mechanism 23e. The second oil supply passage 32e is supplied to the inner ring fitting portion B of the bearing 48 of the main shaft 32, and the third oil supply passage 34e is supplied to the inner ring fitting portion C of the bearing 49 of the drive shaft 34.

  The first oil supply passage 23e branches from the crankshaft passage 23d in a direction perpendicular to the axis, and is formed in the right crank journal portion 23b of the crankshaft 23 so as to communicate with the inner ring fitting portion A. More specifically, the first oil supply passage 23e communicates with an annular groove 23f formed on the outer peripheral surface of the right crank journal portion 23b constituting one surface of the inner ring fitting portion A. The annular groove 23f is located at the axial center of the inner ring 46a of the bearing 46, and has a cross-sectional R shape with a groove depth t of about 0.5 mm and an expansion angle θ of about 120 to 130 °.

  As a result, a portion of the lubricating oil pumped into the crankshaft passage 23d by the oil supply pump 62 is fitted into the inner ring fitting portion A through the annular groove 23f from the first oil supply passage 23e by the centrifugal force of the crankshaft 23. Supplied to the mating surface.

  The second oil supply passage 32e branches from the main shaft passage 32a in a direction perpendicular to the axis, and is formed in the main shaft 23 so as to communicate with the inner ring fitting portion B. The third oil supply passage 34e is formed on the drive shaft. The drive shaft 34 is formed so as to branch from the passage 34a in a direction perpendicular to the axis and communicate with the inner ring fitting portion C. The basic structure is the same as that of the first oil supply passage 23e.

  A part of the lubricating oil pressure-fed into the main shaft passage 32 a of the main shaft 32 by the oil pump 62 is applied from the second oil supply passage 32 e to the fitting surface of the inner ring fitting portion B by the centrifugal force of the main shaft 32. Part of the lubricating oil supplied and pumped into the drive shaft passage 34a of the drive shaft 34 is supplied from the third oil supply passage 34e to the fitting surface of the inner ring fitting portion C by the centrifugal force of the drive shaft.

  According to the present embodiment, since the lubricating oil is supplied to the inner ring fitting portion A in which the bearing 46 of the crankshaft 23 is fitted, the lubricating oil is formed between the crank journal portion 23b of the crankshaft 23 and the inner ring 46a. A damping function is exhibited by entering a slight gap, so that fretting wear due to impact force in the direction perpendicular to the axis acting on the crankshaft 23 can be suppressed, and generation of abnormal noise due to wear can be prevented.

  Since the lubricating oil is supplied to the inner ring fitting portion A of the bearing 46 of the crankshaft 23 in this way, the fitting degree of the bearing 46 to the crankshaft 23 can be made smaller than the fitting degree of the left bearing 45, and the left , Noise can be prevented when the right bearing is firmly press-fitted, and the assembly can be improved.

  In the present embodiment, the oil supply mechanism that supplies the inner ring fitting portion A is configured by the oil supply pump 62 and the first oil supply passage 23e formed in the crankshaft 23, so that the existing lubrication provided in the engine 15 is provided. The oil supply device 60 can be used as it is, and it is only necessary to add diametrical hole machining and grooving to the crankshaft 23, thereby suppressing an increase in cost.

  In the present embodiment, since the annular groove 23f communicating with the first oil supply passage 23e is formed on the outer peripheral surface of the crankshaft 23, the lubricating oil can be supplied over the entire fitting surface of the inner ring fitting portion A. The damping function can be exhibited more reliably.

  In the present embodiment, since the lubricating oil is supplied to the inner ring fitting portions B and C of the main shaft 32 and the drive shaft 34, the main force generated by the reaction force generated when the input gear group 31 and the output gear group 33 are engaged with each other. Fretting wear of the shaft 32 and the drive shaft 34 can be suppressed, and substantially the same effect as in the above embodiment can be obtained.

  In the above embodiment, the case where the lubricating oil is supplied to the inner ring fitting portion has been described. However, the lubricating oil may be supplied to the outer ring fitting portion.

  Also, the case where the crankshaft of the engine, the main shaft of the transmission, and the drive shaft are supported by the left and right unit cases via bearings has been described as an example, but the scope of application of the bearing device of the present invention is limited to this is not. For example, it can also be applied to an intermediate shaft to which the rotation of the crankshaft is transmitted, or a pump shaft. Any of them can be applied.

  Furthermore, in the above embodiment, the engine bearing device mounted on the motorcycle has been described as an example, but the present invention can also be applied to an engine mounted on an automobile or the like.

1 is a side view of a motorcycle on which an engine including a bearing device according to an embodiment of the present invention is mounted. It is a side view of the engine. It is a side view of the oil pump of the engine. It is sectional drawing of the bearing apparatus of the said engine. It is sectional drawing of the bearing apparatus of the said engine. It is sectional drawing of the crankshaft of the said engine. It is a side view of the said crankshaft. FIG. 8 is a cross-sectional view (a cross-sectional view taken along line VIII-VIII in FIG. 6) showing an oil supply passage to the inner ring fitting portion of the crankshaft. It is a schematic block diagram of the lubricating oil path | route of the said engine.

Explanation of symbols

15 Engine 16 Crankcase (case member)
22 Transmission case (case member)
23 Crankshaft (Rotating shaft)
23e Oil supply passage 23f Annular groove 32 Main shaft (transmission shaft)
32e Oil supply passage 34 Drive shaft (transmission shaft)
34e Oil supply passage 41 Bearing device 43, 44 Unit case (case member)
45-50 Bearing 46a Inner ring 46b Outer ring 46c Rolling element 60 Lubricating oil supply device (oil supply mechanism)
62 Oil supply pumps A to C Inner ring fitting part a Cylinder axis

Claims (7)

A bearing device comprising a bearing in which a large number of rolling elements are interposed between an inner ring and an outer ring, a rotating shaft fitted to the inner ring of the bearing, and a case member fitted to the outer ring,
A bearing device comprising an oil supply mechanism that supplies lubricating oil to at least one of an inner ring fitting portion between the inner ring and the rotating shaft or an outer ring fitting portion between the outer ring and the case member. 2. The bearing device according to claim 1, wherein the oil supply mechanism is formed in an oil supply pump and the rotary shaft or the case member, and communicates the oil supply pump with the inner ring fitting portion or the outer ring fitting portion. And a bearing device. 3. The bearing device according to claim 2, wherein the oil supply passage includes an annular groove formed in a portion constituting the inner ring fitting portion of the rotating shaft or a portion constituting the outer ring fitting portion of the case member. A bearing device characterized by that. An engine comprising the bearing device according to any one of claims 1 to 3, wherein the rotary shaft and the case member are a crankshaft and a crankcase, respectively, and the oil supply mechanism supplies lubricating oil to the inner ring and the crank. An engine configured to be supplied to an inner ring fitting portion with a shaft. 5. The engine according to claim 4, wherein the engine is a single-cylinder engine, and both axial side portions sandwiching the connecting rod connecting portion of the crankshaft are supported by the crankcase via a left bearing and a right bearing. The case is divided into a left case and a right case at the portion between the left bearing and the right bearing. The oil supply mechanism fits lubricating oil into the inner ring of either the left or right bearing of the crankshaft. An engine characterized by being configured to be supplied to a part. 6. The engine according to claim 5, wherein the degree of fitting between the crankshaft and the left bearing and the degree of fitting between the crankshaft and the right bearing have different values, and the oil supply mechanism supplies the lubricating oil to the degree of fitting. An engine that is configured to be supplied to an inner ring fitting portion on a loose side of the engine. An engine including the bearing device according to any one of claims 1 to 3, wherein the rotation shaft and the case member are a transmission shaft and a transmission case, respectively, and the oil supply mechanism is configured to supply lubricating oil to the inner ring and the An engine configured to be supplied to an inner ring fitting portion with a transmission shaft.

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