JP2009138616A - Camshaft support structure for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize good rotation support performance and good durability of a camshaft in a support structure of the camshaft for an engine using a rolling bearing and an inner race. <P>SOLUTION: This structure includes cam parts 111-114 opening intake and exhaust valves of a plurality of cylinders arranged in a row, and journal parts 121-124 provided for each cylinder, and is rotatably supported by each journal part via the inner race including the rolling bearing and a joint 51. The structure is provided with positioning means 15, 52 positioning the joint 51 of the inner race 40 at a section avoiding a phase at which valve repulsion force gets the maximum when the valves open in the cylinder and the adjacent cylinder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a camshaft support structure for an engine, and more particularly to a structure for camshaft support using a rolling bearing, and belongs to the technical field of a valve mechanism in an engine for an automobile or the like.

  An overhead camshaft of an engine having a plurality of cylinders arranged in a row has a cam portion that opens an intake valve or an exhaust valve of each cylinder and a journal portion provided between the cam portions, It is rotatably supported by being sandwiched between a semicircular bearing surface provided on the upper surface of the cylinder head and a semicircular bearing surface provided on the bearing cap. However, in recent years, in order to reduce the rotational resistance of the camshaft, for example, as described in Patent Document 1, a rolling bearing is sometimes used for the bearing portion.

  This rolling bearing is usually a structure in which a large number of rollers are held in an annular holder divided into two parts or provided with a dividing part at one place, and these rollers roll on the outer peripheral surface of the journal part of the camshaft. However, an inner race may be attached to the outer peripheral surface of the journal portion in order to improve the rotational support performance and durability performance at that time. In particular, when the roller is made of steel and the camshaft is made of cast iron, the necessity becomes high.

JP 2006-183837 A

  By the way, the inner race is provided with a dividing portion at one place, and the dividing portion is opened to be attached to the journal portion of the camshaft. In this case, the following problems may occur.

  That is, as shown in FIG. 13, when the inner race 1 is attached to the journal portion 2a of the camshaft 2, the dividing portion generates a small gap 1a, and a roller of the rolling bearing 3 is formed on the joint 1a. 3a passes through, but in this case, the maximum lift portion where the valve reaction force from the tappet 4 side when the valve opening 1a is opened, that is, the cam 2b most strongly presses the tappet 4. When the roller 3a is located at the opposite side of 180 °, the roller 3a passes through the mating port 1a while receiving a large load.

  Therefore, when the roller 3a passes, a minute rattling or an impact occurs, and the rotation support performance of the rolling bearing 3 with respect to the cam shaft 2 is deteriorated, or the inner race 1 and the roller 3a are damaged, so that the durability thereof is increased. It is considered that there are problems such as lowering the performance.

  Accordingly, an object of the present invention is to realize a good rotational support performance for the cam shaft and a good durability of the inner race and the rolling bearing in the cam shaft supporting structure using the rolling bearing and the inner race.

  In order to solve the above problems, the present invention is configured as follows.

  First, the invention according to claim 1 includes a cam portion that opens intake and exhaust valves of a plurality of cylinders arranged in a row, and a journal portion provided for each cylinder, and each journal portion includes a rolling bearing and an inner race. In the camshaft support structure that is rotatably supported via the inner race, the inner race has an abutment that is divided at one place, and the position of the abutment is determined when the cylinder and the adjacent cylinder are opened. Positioning means is provided for positioning at a portion that avoids the phase where the valve reaction force of the valve is the largest.

  According to a second aspect of the present invention, in the camshaft support structure according to the first aspect, the abutment is a mountain shape that is symmetrically inclined toward the both sides from the center in the width direction of the inner race. It is said that it is said.

  According to a third aspect of the present invention, in the camshaft support structure according to the first or second aspect, the inner race positioning means is inserted into a hole provided in a journal portion of the camshaft. It is comprised by the pin-shaped part, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the camshaft support structure according to the third aspect, the hole provided in the journal portion is an oil passage provided in the camshaft in the axial direction. The oil passage is a radial oil passage communicating with the surface, and the pin-like portion inserted into the oil passage forms an orifice for narrowing the opening of the oil passage.

  The invention according to claim 5 is the camshaft support structure according to any one of claims 1 to 4, wherein the camshaft is made of cast iron, and the rollers of the inner race and the rolling bearing are steel. It is made of.

  With the above configuration, according to each invention of the present application, the following effects can be obtained.

  According to the first aspect of the present invention, when the inner race is mounted on the journal portion provided on the camshaft for each cylinder, the positioning means for the journal portion of the inner race is provided. The phase relationship between each cam of the cam shaft and the joint of each inner race is fixed.

  In this case, the abutment is a portion that avoids the phase of the camshaft where the valve reaction force at the time of valve opening is greatest in the cylinder in which the inner race is mounted and the adjacent cylinder, specifically the cylinder and the adjacent Since the maximum lift of the cam of the cylinder to be fixed is fixed at a portion that is opposite to the 180 ° opposite side, when the cylinder and the adjacent cylinder are opened, there is an abutment at a portion where the valve reaction force in the inner race becomes the largest. It will not exist.

  Therefore, the occurrence of minute rattling and impact due to the roller of the rolling bearing passing over the joint of the inner race while receiving a large load is avoided, and the durability of the inner race and the rolling bearing is prevented from being lowered. At the same time, good rotation support performance for the cam shaft of the rolling bearing is maintained.

  In particular, according to the present invention, not only the phase relationship with the cam of the cylinder but also the phase relationship with the cam of the adjacent cylinder is considered when setting the position of the inner race junction for each cylinder. Further, the influence of the valve reaction force generated in the adjacent cylinder at the time of valve opening being transmitted to the cylinder is avoided, and the above effect is achieved more reliably.

  According to the invention described in claim 2, since the joint is formed in a mountain shape that is symmetrically inclined from the center in the width direction of the inner race toward both sides, the joint is formed in the inner race. As in the case of being provided linearly in the width direction, the roller gradually passes over the joint without falling into the joint. In addition, since the slope is a symmetrical mountain shape, the roller is not tilted in the tilt direction of the abutment as in the case of tilting in one direction.

  Therefore, the roller of the rolling bearing smoothly passes over the inner race joint, so that better rotation support performance with respect to the cam shaft can be obtained.

  According to the invention described in claim 3, since the positioning means of the inner race is constituted by a pin-like portion inserted into a hole provided in the journal portion of the cam shaft, the positioning of the inner race can be performed. It will be done easily. In that case, the pin-shaped portion may be provided integrally with the inner race, or may be used separately.

  According to the fourth aspect of the present invention, as the inner race positioning hole provided in the journal portion, a radial oil passage provided in the camshaft in the axial direction communicates with the outer peripheral surface of the journal portion. Since the oil passage is used and the pin-like portion inserted into the hole forms an orifice for narrowing the opening of the oil passage, the means for supplying the lubricating oil and the positioning means for the inner race are combined. As a result, the complication of the configuration of the journal part is suppressed.

  Further, according to the invention described in claim 5, when the camshaft is made of cast iron and the roller of the rolling bearing is made of steel, the roller also rolls on the inner race made of steel. Therefore, compared with the case where the steel roller rolls on the outer peripheral surface of the cast iron journal portion, the rotation support performance and durability performance of the rolling bearing are improved.

  Embodiments of the present invention will be described below.

First, the configuration of the camshaft 10 according to the first embodiment will be described with reference to FIG. 1. This camshaft 10 is an intake or exhaust camshaft of an in-line four-cylinder engine, and is first to first from the front end side. 4 cylinder # 1 to # 4 for the cam with ₄ 11 1 to 11 (hereinafter, first to fourth that _cam) is provided in pairs, between the pair of cams for each cylinder, first to fourth The journal portions 12 _{1 to} 12 ₄ are used.

  Further, a sprocket mounting flange 13 is provided at an end portion on the first cylinder # 1 side, and a sprocket (not shown) around which a chain mounted between the crankshaft and the crankshaft is wound is attached to the flange 13. It is like that. A front journal 14 is provided behind the flange 13.

Here, the firing order of this engine is a # 1 → # 3 → # 4 → # 2, the first to fourth cam ₁₁ 1 to 11 _4, 90 ° in this order in the direction opposite to the rotational direction X The phase is shifted one by one.

Next, referring to FIGS. 2 and 3, the structure of the bearing 20 that supports the camshaft 10 will be described by taking the first cylinder # 1 as an example. The bearing 20 is an upper open semicircle provided on the upper surface of the cylinder head 21. Bearing surface 21a, and a lower-opening semicircular bearing surface 23a provided on a bearing cap 23 attached to the upper surface of the cylinder head 21 using bolts 22 and 22, and these bearings surface 21a, between 23a, the journal portion 12 ₁ of the cam shaft 10, an outer race 30, 30 of the two-split type from the outside, is rotatably clamped via a rolling bearing 40 and the inner race 50.

The inner race 50, as shown in FIG. 4, in a shape to divide the circular ring at one place, being adapted to wind on the outer circumferential surface of the journal portion 12 ₁ is opened the segmented portion, in a state in which winding has, An abutment 51 is formed with the divided ends facing each other with a small gap. In this case, the abutment 51 has a mountain shape that is axisymmetrically inclined from the center toward both sides with the center line in the width direction of the inner race 50 as the axis of symmetry.

Further, as shown in FIG. 2, a pin-like portion 52 that protrudes inward is provided in the vicinity of one end portion that forms the abutment 51, and the pin-like portion 52 is a journal portion 12 of the camshaft 10. by being inserted into radial bores 15 provided in the _1, is restricted from moving in the axial direction and the rotational direction of the inner race 50 of the on the journal portion 12 _1, in particular by restricting the movement of the rotation direction, the The phase of the abutment 51 with respect to the cam shaft 10 is positioned at a predetermined phase.

  The radial hole 15 of the camshaft 10 constitutes an oil passage that communicates with the outer peripheral surface of the journal portion in the axially extending lubricating oil passage 16 provided in the camshaft 10. The pin-shaped portion 52 of the inner race 50 is provided with a through hole 53 that communicates the inside and outside of the inner race 50, and the through hole 53 is an orifice provided in the opening of the oil passage (hole) 15. Is configured.

  On the other hand, as shown in FIG. 5, the rolling bearing 40 has a configuration in which a plurality of rollers 42... 42 that are long in the axial direction are arranged in parallel in an annular holder 41 and held rotatably. In the case of this form, the holder 41 is divided at one place, and the divided portion 41a is opened, and the holder 41 is attached to the outer side of the inner race 50 wound around the outer peripheral surface of the journal portion 121. A split type rolling bearing in which the holder 41 is divided into two parts may be used.

  In this embodiment, a plurality of claws 41b... 41b projecting inward are provided on both sides of the holder 41, and as shown in FIG. 3, the inner claws 41b and 41b are disposed between the inner claws 41b and 41b. By holding the race 50 from both sides in the width direction, the movement of the rolling bearing 40 in the axial direction is restricted.

  The configuration of the bearing 20 described above is the same for the second to fourth cylinders # 2 to # 4 except for the phase of the mating port 51 in the inner race 50 with respect to the camshaft 10.

  In this embodiment, the camshaft 10 is cast iron, and the outer race 30, the roller 42 of the rolling bearing 40 and the inner race 50 are formed of steel.

  Next, referring to FIG. 6, the phase of the joint 51 in the inner race 50 with respect to the cam shaft 10 will be described.

First, the first cylinder # 1, as shown in FIG. (1), by insertion of the pin-shaped portion 52 in the radial direction of the hole 15 of the journal portion 12 _1, the position of the abutment 51 of the inner race 50, a portion a corresponding to the 180 ° opposite side of the phase of the maximum lift of the cam 11 ₁ of the first cylinder # 1, the 180 ° opposite side of the maximum lift of the cam 11 of the _second cylinder # 2 adjacent phase It is positioned in a range alpha ₁ that avoids the site B corresponding to.

In the second cylinder # 2, as shown in FIG. (2), the position of the abutment 51 of the inner race 50, the maximum lift portion of the second cylinder # 2 of cam 11 ₂ a 180 ° opposite a portion B corresponding to the phase, a portion a corresponding to the first cylinder # 1 of the 180 ° opposite to the phase of the maximum lift of the cam 11 ₁ adjacent to the one, the third cylinder # 3 of a cam adjacent to the other It is positioned in a range alpha ₂ that avoids the site C corresponding to 11 ₃ of the 180 ° opposite to the phase of the maximum lift portions.

Further, in the third cylinder # 3, as shown in FIG. 3, the position of the abutment 51 of the inner race 50, the maximum lift of the cam 11 ₃ of the third cylinder # 3 of 180 ° opposite a part C corresponding to the phase, the portion B corresponding to the second cylinder # of 180 ° opposite to the maximum lift of the cam 11 ₂ 2 phase adjacent one, the fourth cylinder # 4 of a cam adjacent to the other It is positioned in a range alpha ₃ that avoids the site D corresponding to 180 ° opposite the phase of the maximum lift of 11 _4.

Then, in the fourth cylinder # 4, as shown in FIG. 4, the position of the abutment 51 of the inner race 50, the maximum lift of the fourth cylinder # 4 of the cam 11 ₄ 180 ° opposite a portion D corresponding to the phase, and is positioned in a range alpha ₄ to avoid the site C corresponding to 180 ° opposite the phase of the maximum lift of the cam 11 ₃ of the third cylinder # 3 adjacent.

According to the setting of the position of the abutment 51 as described above, in any of the cylinders, when the greatest valve reactive force to the rolling bearing 40 to the cam 11 ₁ to 11 ₄ is opened the intake valve or the exhaust valve site of action, i.e., abutment 51 of the inner race 50 is not present in the site A~D corresponding to 180 ° opposite the phase of the maximum lift of each cam ₁₁ 1 to 11 _4.

  Therefore, it is avoided that the roller 42 of the rolling bearing 40 receives a large load when passing over the mating joint 51 of the inner race 50, and the roller 42 becomes minute by passing over the mating joint 51 while receiving a large load. The occurrence of rattling or impact is prevented.

  In this case, the position of the abutment 51 in each of the cylinders # 1 to # 4 is not only the portion where the valve reaction force becomes the largest when the cylinder is opened, but the valve reaction force is the largest when the adjacent cylinder is opened. Therefore, the influence of the valve reaction force generated when the valve is opened in the adjacent cylinder is transmitted to the cylinder is also avoided. Therefore, the above-described problem due to the roller 42 passing over the abutment 51 while receiving a load is more effectively prevented.

  Further, since the joint 51 has a mountain shape that is symmetrically inclined from the center in the width direction of the inner race 50 toward both sides, the joint 51 is provided linearly in the width direction of the inner race 50. The roller 42 gradually passes over the joint 51 without falling into the joint 51 as in the case where it is formed. Further, since the inclination is left-right symmetric, the roller 42 is not inclined in the inclination direction of the abutment 51 as in the case where the inclination is in one direction. Therefore, the roller 42 of the rolling bearing 40 passes smoothly over the mating port 51 of the inner race 50, and better rotation support performance for the cam shaft 10 is obtained.

Further, according to this embodiment, the lubricating oil passage 16 provided in the camshaft 10 in the axial direction is used as the inner race positioning hole 15 provided in each of the journal portions 12 _{1 to} 12 _4. A radial oil passage communicating with the oil passage is used, and the pin-like portion 52 of the inner race 50 inserted into the hole 15 constitutes an orifice for narrowing the opening of the oil passage (hole) 15. oil passage 16 for supplying oil will be also used as positioning means for the inner race 50, complication of the configuration of the journal portion 12 ₁ to 12 ₄ can be suppressed.

  Further, in this embodiment, the camshaft 10 is made of cast iron, and the roller 42 of the rolling bearing 40 is made of steel, but the inner race 50 and the outer race 30 on which the roller 42 rolls directly are made of steel. Therefore, the roller 42 rolls well, and the rotation support performance and durability performance of the rolling bearing 40 are improved.

  Next, a second embodiment in which the present invention is applied to a camshaft of an in-line 6-cylinder engine will be described.

As shown in FIG. 7, in the camshaft 110 according to this embodiment, the maximum lift portion of the cam of each cylinder is arranged at a position that divides the entire circumference into six equal parts. The ignition order of this engine is # 1. → # 5 → # 3 → # 6 → # 2 → # a 4, first to sixth cam ₁₁₁ 1-111 ₆ is 60 ° out of phase in this order is shifted in the opposite direction of the rotational direction X Yes.

Other configurations, for example, rolling bearings 140 and configuration of the inner race 150, and the radial journal portion ₁₁₂ 1-112 _6-pin shaped portion 152 and the pin-shaped portion 152 for positioning the inner race 150 is inserted The configuration of the holes 115 and the like is the same as that in the first embodiment.

  In the second embodiment, the phase of the joint 151 in the inner race 150 with respect to the cam shaft 110 is set as shown in FIG.

First, the first cylinder # 1, as shown in FIG. (1), the position of the abutment 151 of the inner race 150, the 180 ° opposite side of the first cylinder # maximum lift of the cam 111 ₁ of 1 'and, site B corresponding to the 180 ° opposite side of the maximum lift of the cam 111 of the _second cylinder # 2 adjacent phase' site a corresponding to the phase is positioned in a range beta ₁ avoiding the.

In the second cylinder # 2, as shown in FIG. (2), the position of the abutment 151 of the inner race 150, the maximum lift portion of the second cylinder # 2 of the cam 111 _{and second} 180 ° opposite site B corresponding to the phase and 'a, part a corresponding to the 180 ° opposite side of the phase of the maximum lift of the cam 111 of the _first cylinder # 1 which is adjacent to one', the third cylinder # 3 adjacent to the other is positioned in a range beta ₂ that avoids the site C 'corresponding to of 180 ° opposite to the maximum lift of the cam 111 ₃ phase.

Further, in the third cylinder # 3, as shown in FIG. 3, the position of the abutment 151 of the inner race 150, the maximum lift of the cam 111 ₃ of the third cylinder # 3 of 180 ° opposite site C corresponding to the phase and 'a, part B corresponding to the 180 ° opposite side of the phase of the maximum lift of the cam 111 of the _second cylinder # 2 adjacent to one', the fourth cylinder # 4 adjacent to the other It is positioned in a range beta ₃ that avoids the site D 'corresponding to the 180 ° opposite to the phase of the maximum lift portion of the cam 111 _4.

Further, in the fourth cylinder # 4, as shown in FIG. 4, the position of the abutment 151 of the inner race 150, the maximum lift of the fourth cylinder # 4 of the cam 111 ₄ 180 ° opposite site D corresponding to the phase and 'a, part C corresponding to the third cylinder # of 180 ° opposite to the maximum lift of the third cam 111 ₃ phase adjacent to one', fifth cylinder # 5 adjacent to the other It is positioned in a range beta ₄ to avoid the site E 'corresponding to the 180 ° opposite to the phase of the maximum lift portion of the cam 111 _5.

Further, in the fifth cylinder # 5, as shown in FIG. 5, the position of the abutment 151 of the inner race 150, the maximum lift of the cam 111 ₅ of fifth cylinder # 5 of the 180 ° opposite side site E corresponding to the phase and 'a, part D corresponding to the fourth cylinder # of 180 ° opposite to the maximum lift of the fourth cam 111 ₄ phase adjacent to one', sixth cylinder adjacent to the other # 6 It is positioned in a range beta ₅ avoiding a site F 'corresponding to of 180 ° opposite to the maximum lift portion of the cam 111 ₆ phase.

Then, in the sixth cylinder # 6, as shown in FIG. 6, the position of the abutment 151 of the inner race 150, the maximum lift of the cam 111 ₆ sixth cylinder # 6 of 180 ° opposite 'and, site E corresponding to 180 ° opposite the phase of the maximum lift of the cam 111 ₅ of the fifth cylinder # 5 adjacent' site F corresponding to the phase is positioned in a range beta ₆ avoiding the.

Therefore, also in this embodiment, in each cylinder, the cams 111 _{1 to} 111 ₆ that exert the largest valve reaction force on the rolling bearing 140 when the cams 111 ₁ to 11 ₁₆ open the intake valves or the exhaust valves. In other words, the joint 151 of the inner race 150 does not exist in the portions A ′ to E ′ corresponding to the phase on the opposite side of 180 ° of the maximum lift portion, and the roller 142 of the rolling bearing 140 is connected to the joint 151 of the inner race 150. Problems caused by receiving a large load when passing over are prevented.

  In addition, the phase of the abutment in each cylinder # 1 to # 6 is not only the portion where the valve reaction force becomes the largest when the cylinder opens, but also the phase where the valve reaction force becomes the largest when the adjacent cylinder opens. Since the corresponding part is also set to avoid, the above problem can be prevented more effectively.

  In the first and second embodiments, as a means for positioning the inner races 50, 150 on the journal portions of the camshafts 10, 110, the pin-shaped portion 52 that protrudes inwardly to the inner races 50, 150 is provided. 152 is inserted into the radial holes 15 and 115 provided in the journal portion. However, as shown in FIG. 9, a hole 252 is opened in the vicinity of the mating hole 251 in the inner race 250. The pin member 260 may be press-fitted across the hole 252 and the radial hole 215 provided in the journal portion of the cam shaft 210.

  Also in this case, when the through hole 261 is provided in the pin member 260 and the hole 215 is an oil passage for supplying lubricating oil from the lubricating oil passage 216 inside the camshaft to the outer peripheral surface of the journal portion, the through hole 261 is provided. Can be configured as an orifice.

  By the way, with respect to the front journal portion 14 shown in FIG. 1, a load is always applied from the crankshaft through the chain, so that the load is evenly applied to the entire circumference of the journal portion 14. Therefore, when the inner race having the abutment as described above is used, the roller of the rolling bearing passes over the abutment while receiving a load.

  Therefore, the camshaft 310 shown in FIG. 10 is configured such that the sprocket mounting flange 311 at the front end is separated from the camshaft 310 and is fixed to the front end of the camshaft 310 by a bolt 313 together with the sprocket 312. Yes.

  According to this configuration, before fixing the flange 311 to the camshaft 310, the front journal portion 314 can be fitted with the unseparated inner race 350 having no joint, and the roller of the rolling bearing 340 can be fitted. It is possible to avoid the situation of passing over the abutment while receiving a load. Further, according to this configuration, it is possible to use an integral type as the rolling bearing 340, and better rotation support performance can be obtained.

  11 and 12 show a configuration example of the front journal portion of the crankshaft in relation to the present invention. In the configuration example shown in FIG. 11, a double sprocket is provided at the front end portion of the crankshaft 410. 420 is fitted and fixed, and a front journal part 411 is provided at the rear thereof, and a rolling bearing 430 attached to the journal part 411 is inserted into a bearing hole 441 provided in the cylinder block 440 via an outer race 450. It is mated. In this configuration example, a flange portion 412 is provided immediately in front of the journal portion 411 so as to prevent the rolling bearing 430 attached to the journal portion 411 from coming off in the axial direction.

  In the case of this configuration example, since the rolling bearing 430 cannot be fitted to the journal portion 411 from the front of the crankshaft 410, a two-split type is used as the bearing 430.

  Also in the configuration example shown in FIG. 12, a double sprocket 520 is fitted and fixed to the front end portion of the crankshaft 510, and a front journal portion 511 is provided behind the sprocket 520 and attached to the journal portion 511. The thus-rolled bearing 530 is fitted into a bearing hole 541 provided in the cylinder block 540 via an outer race 550.

  In this configuration example, a flange portion 521 is provided at the rear end portion of the dual sprocket 520, and the flange portion 521 prevents the rolling bearing 530 fitted to the journal portion 511 from coming off. Yes.

  According to this configuration example, since the rolling bearing 530 can be fitted to the journal portion 511 before the sprocket 520 is fitted, a non-split type can be used as the rolling bearing 530.

  As described above, according to the present invention, as a cam shaft support structure, a structure having good rotation support performance and excellent durability performance for the cam shaft is realized. In the industrial field, it may be suitably used.

1 is an overall perspective view of a cam shaft according to an embodiment of the present invention. It is sectional drawing of the bearing part of a cam shaft. It is sectional drawing of the same bearing cut | disconnected by the YY line | wire of FIG. It is a perspective view of an inner race. It is a perspective view of a rolling bearing. It is explanatory drawing of the phase of the inner race entrance in the journal part of each cylinder. It is sectional drawing of the cam shaft which concerns on 2nd Embodiment. It is explanatory drawing of the phase of the inner race entrance in the journal part of each cylinder of the embodiment. It is sectional drawing of the other example of the positioning means of an inner race. It is sectional drawing of the other example of the front journal part of a cam shaft. It is sectional drawing of the front journal part of a crankshaft. It is sectional drawing of the other example of the front journal part of a crankshaft. It is explanatory drawing of the conventional problem.

Explanation of symbols

10,110 camshaft 11 ₁ to 11 _{4, 111} 1 to 111 ₆ the cam 12 ₁ to 12 _{4, 112} 1 to 112 ₆ the journal portion 15, 115 holes 40, 140 rolling 42,142 rollers 50, 150 inner race 51, 151 Abutment 52, 152 Pin-shaped part

Claims (5)

A cam shaft having a cam portion that opens intake and exhaust valves of a plurality of cylinders arranged in a row and a journal portion provided for each cylinder, and is rotatably supported by each journal portion via a rolling bearing and an inner race In the support structure of
The inner race has a joint that is divided at one place,
A camshaft support for an engine, characterized in that positioning means is provided for positioning the position of the abutment at a portion that avoids a phase where the valve reaction force during valve opening becomes maximum in the cylinder and the adjacent cylinder. Construction. The camshaft support structure according to claim 1,
The camshaft support structure for an engine, wherein the abutment has a mountain shape that is symmetrically inclined from the center in the width direction of the inner race toward both sides. In the camshaft support structure according to claim 1 or 2,
The inner race positioning means is constituted by a pin-like portion inserted into a hole provided in a journal portion of the cam shaft. In the camshaft support structure according to claim 3,
The hole provided in the journal portion is a radial oil passage that communicates an oil passage provided in the axial direction in the camshaft with the outer peripheral surface of the journal portion,
A cam shaft support structure for an engine, wherein the pin-like portion inserted into the oil passage constitutes an orifice for narrowing the opening of the oil passage. In the camshaft support structure according to any one of claims 1 to 4,
A camshaft support structure for an engine, wherein the camshaft is made of cast iron, and the inner race and the roller of the rolling bearing are made of steel.

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