JP2005106270A - Split type connecting rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a split type connecting rod capable of suppressing turning of a bearing metal with a simple structure and securely avoiding problems such as seizure. <P>SOLUTION: The split type connecting rod 200 holds a crank pin through the bearing metal 213 having locking claws 213c, 213d. A bearing locking groove 201h locks at least one locking claw 213d when the bearing metal 213 forwardly rotates in the circumferential direction of a crank pin hole 101d. A bearing locking groove 201i locks at least one locking claw 213c when the bearing metal 213 rotates in the reverse direction. The bearing locking grooves 201h, 201i are positioned in a deviated state from each other in the circumferential direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a split-type connecting rod, and more particularly to a split-type connecting rod in which a bearing is disposed in a crankpin hole.

  The split connecting rod is configured to split the large end into a rod part and a cap part with a split surface including the axis of the crankpin hole, and to connect the rod part and the cap part with a connecting bolt. In general, a bearing metal is disposed on the inner peripheral surface of the crank pin hole.

The bearing metal is divided into a rod side portion and a cap side portion at the dividing surface, and when such a divided type bearing metal is disposed within the inner peripheral surface of the crankpin hole, the bearing metal is provided on the inner peripheral surface. Generally, the locking groove is formed to extend in the circumferential direction, and the locking claw protruding from the back surface (outer peripheral surface) of the bearing metal is locked to the bearing locking groove to position the bearing metal. (For example, see Patent Document 1).
JP-A-6-74237

  However, in the case of the conventional split type connecting rod, there is a problem that the bearing metal easily rotates in the circumferential direction due to an external force, and a reliable lubricating structure is required to prevent seizure due to this. In particular, in the case of a motorcycle engine that tends to be used at high speed rotation, for example, there is a problem that the amount of deformation at the large end is large and the amount of rotation of the bearing metal is likely to increase accordingly.

  In order to solve the above problems, the embodiment of the present invention provides a split connecting rod that can suppress the rotation of the bearing metal with a simple structure and can reliably avoid problems such as seizure.

  The split type connecting rod of the present invention is a split type connecting rod that grips a crank pin via a bearing having a protrusion. When the bearing rotates forward in the circumferential direction of the crank pin hole, the first protrusion of the bearing is provided. A first locking groove for locking, and a second locking groove for locking the second protrusion of the bearing when the bearing rotates in the reverse direction, the first locking groove and the first The two locking grooves adopt a configuration in which they are offset from each other in the circumferential direction.

  According to this configuration, the first locking groove for locking the first protrusion of the bearing (for example, bearing metal) and the second locking groove for locking the second protrusion of the bearing are mutually circumferential. For example, when a bearing in which the first protrusion and the second protrusion are arranged substantially in parallel in the crankpin hole axial direction is inserted into the crankpin hole, The movable range of each protrusion can be minimized, and therefore the rotation of the bearing can be suppressed with a simple structure, and problems such as seizure can be reliably avoided.

  In the split connecting rod of the present invention, in the above configuration, the first locking groove and the second locking groove have the rod portion and the cap when the large end portion is broken and divided into the rod portion and the cap portion. The first locking groove is displaced on the rod part side, and the second locking groove is displaced on the cap part side. .

  According to this configuration, the first locking groove and the second locking groove straddle both the rod portion and the cap portion, the first locking groove is displaced to the rod portion side, and the second locking groove is the cap portion. For example, when the bearing is a split-type bearing metal and the bearing has first and second protrusions at one circumferential end on the back surface, the first locking groove is on the cap portion side. The first protrusion can be locked at the end, and the second locking groove can lock the second protrusion at the rod side end, and the movement of each protrusion toward the rod and the cap Both movement to the side can be prevented.

  The engine of this invention takes the structure which has said division | segmentation type | mold connecting rod.

  According to this structure, the effect similar to said split type connecting rod is realizable in an engine.

  The vehicle of this invention takes the structure which has said division | segmentation type | mold connecting rod.

  According to this structure, the effect similar to said split type connecting rod is realizable in a vehicle.

  As described above, according to the present invention, the rotation of the bearing metal can be suppressed with a simple structure, and problems such as seizure can be reliably avoided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The split connecting rods of the present invention described in all the embodiments below can be used in an engine for a vehicle such as a motorcycle.

(Embodiment 1)
1-4 is a figure for demonstrating the split type connecting rod which concerns on Embodiment 1 of this invention. 1 is a front view of a split-type connecting rod, FIG. 2 is a cross-sectional view of the large-end portion of the split-type connecting rod, FIGS. 3A and 3B are enlarged views of a fracture starting groove at the large end, and FIG. It is a figure which shows a method.

  In these figures, reference numeral 100 indicates the split type connecting rod of the present embodiment, preferably a nutless type connecting rod formed by forging, casting or sintering or other suitable process. The split connecting rod 100 has a small end portion 101c having a piston pin hole 101b on one end side of a rod body 101a, and a large end portion 101e having a crank pin hole 101d on the other end side.

  The large end portion 101e has a shoulder portion 101f extending from the connecting portion with the rod main body 101a to the left and right outer sides, and a crankpin hole 101d is formed at a central portion between both shoulder portions 101f. Each shoulder portion 101f of the large end portion 101e is formed with a bolt hole 101g extending close to the upper surface from the lower surface of the large end portion 101e.

  In the large end portion 101e, the rod portion 102 and the cap portion 103 are preferably integrated and define a single unified structure that is formed in advance. The split type connecting rod 100 including the large end 101e is subjected to surface hardening treatment such as carburizing and tempering. The large end 101e is broken and divided into a rod portion 102 and a cap portion 103 along a planned fracture surface (straight line A in the figure). As shown in FIG. 4, the rod part 102 and the cap part 103 can be divided by placing the split type connecting rod 100 on the base 110 and moving in the diametrical direction into the crank pin hole 101d of the large end part 101e. This is done by inserting a simple slider 111 and driving a wedge 112 between the sliders 111.

  The broken and divided rod portion 102 and cap portion 103 are coupled by fastening bolts 104 screwed into the respective bolt holes 101g in a state in which the broken divided surfaces are brought into contact with each other and aligned.

  A surface hardened layer having a predetermined carburization depth is formed on the outer peripheral surface portion of the split connecting rod 100 by the surface hardening treatment. In addition to carburizing and tempering, nitriding, thermal spraying, vapor deposition, induction hardening, or other suitable treatments can be used for the surface hardening treatment.

  A pair of fracture starting grooves 105 extending in the axial direction of the crankpin hole 101d is formed on the inner peripheral surface of the crankpin hole 101d. Each break starting groove 105 is formed by cutting, wire cutting (wire cut electric discharge machining), machining using a laser, or other appropriate processing, and is formed by the rod portion 102 of the large end 101e. And the cap portion 103 are formed along a line of intersection between the planned fracture surface (indicated as a straight line A in the drawing) and the inner peripheral surface. That is, for example, when the fracture starting groove 105 is formed by wire cutting, a conductive wire is arranged in the vicinity of a predetermined position on the inner peripheral surface of the crankpin hole 101d, and a pulse is generated between the conductive wire and the inner peripheral surface of the crankpin hole 101d. A high voltage is applied. As a result, a corona discharge is caused between the conductive wire and the inner peripheral surface of the crankpin hole 101d, and a part of the inner peripheral surface of the crankpin hole 101d is scraped off by this discharge to form a fracture starting groove 105.

  A trough 106 is formed between the inner peripheral surface of the crank pin hole 101d and the fracture starting groove 105. The trough portion 106 is formed by chamfering the upper and lower corner portions formed by the fracture starting groove 105 and the inner peripheral surface of the crank pin hole 101d. Preferably, the valley 106 has an opening width wider than that of the fracture starting groove 105. The valley 106 is preferably formed at the same time when the split connecting rod 100 is formed by forging, casting, sintering, or other suitable processing, as in the break starting groove 105, by machining such as wire cutting. It has been done.

  As shown in FIGS. 2, 3A and 3B, the inclined portion 106a constituting the valley portion 106 is preferably a straight line A passing from the axis a of the crankpin hole 101d to the bottom portion 105a of the bottom surface 105c of the fracture starting groove 105. It is formed by notching linearly so that the angle β formed with the (scheduled fracture surface) is preferably about 45 degrees. As a result, the interior angle of the valley 106 is about 90 degrees. Further, the upper and lower inner surfaces 105b, 105b of the breaking start groove 105 are formed so that the angle α formed with the straight line A is approximately 0 degrees, that is, substantially parallel to the straight line A.

  Furthermore, the trough 106 preferably has an opening width L4 that is larger than the opening width L3 of the fracture starting groove 105. As a result, the inclined portion 106a constituting the valley portion 106 functions as a chamfer when a bearing metal (not shown) divided into two in the crank pin hole 101d is inserted in the bolt hole 101g direction.

  Here, the function of the inclined portion 106a as a chamfered portion will be described. When the corner portion is not chamfered, the bearing metal comes into contact with the corner portion when the bearing metal is attached to the crank pin hole. The surface of the bearing metal is subjected to metal plating such as Sn (tin) plating as a corrosion-resistant layer. When this plating layer comes into contact with a sharp corner portion formed by fracture division, a part of the plating layer is scraped off into particles, and these particles adhere to the fracture division surface. The adhering particles obstruct high-precision recombination of the split connecting rod. On the other hand, when chamfering is performed on the corner portion, that is, when the valley portion 106 is formed, a part of the plating layer is difficult to be scraped off, which is an obstructive factor for high-precision recombination of the split connecting rod. Generation of particles can be suppressed.

  The ratio of the groove depth L2 of the breaking start groove 105 to the shortest distance L1 from the base point of the breaking starting groove 105 (that is, the boundary point 107 between the inner surface 105b and the inclined portion 106a) to the edge of the bolt hole 101g is preferably It is set to about 70% or more.

  As described above, according to the present embodiment, the pair of fracture starting grooves 105 extending in the axial direction is formed on the inner peripheral surface of the crankpin hole 101d, and the inner peripheral surfaces of the respective fracture starting grooves 105 and the crankpin hole 101d. The inclined portion 106a is formed at the upper and lower corner portions. The trough 106 preferably has an opening width L4 that is wider than the opening width L3 of the breaking start groove 105. In other words, the angle β formed with the straight line A of the valley portion 106 is preferably larger than the angle α formed with the fracture starting groove 105. As a result, the ratio of the groove depth L2 of the fracture starting groove 105 to the shortest distance L1 from the base point of the fracture starting groove 105 to the edge of the bolt hole 101g with the inner peripheral surface of the crankpin hole 101d as a base point can be increased. In addition, a hardened layer can be reliably formed by the surface hardening process up to the bottom 105a of the break starting groove 105. As a result, the stress intensity factor at the bottom 105a of the break starting groove 105 can be increased, and the occurrence of peeling or chipping during break splitting can be prevented, and problems such as damage or seizure due to chipping during engine operation can be prevented.

(Embodiment 2)
FIG. 5A, FIG. 5B, FIG. 6 and FIG. 7 are diagrams for explaining a split connecting rod according to Embodiment 2 of the present invention. 5A is a front view of the split type connecting rod of the present embodiment, FIG. 5B is a VV sectional view of the split type connecting rod shown in FIG. 5A, and FIG. 6 is a VI-VI cross sectional view of the split type connecting rod shown in FIG. 7 is a sectional view taken along the line VII-VII of the split connecting rod shown in FIG. 5B. The split connecting rod described in the present embodiment preferably has the same basic configuration as that of the split connecting rod 100 described in the first embodiment, and is the same or corresponding to each other in both embodiments. The same reference numerals are assigned to the constituent elements, and the detailed description thereof is omitted.

  In the split connecting rod 200 of the present embodiment, a substantially ring-shaped bearing metal 213 is disposed on the inner peripheral surface of the crankpin hole 101d. The bearing metal 213 is divided into a rod-side bearing metal portion 213a and a cap-side bearing metal portion 213b along a dividing line whose fracture surface (straight line A) intersects the crank pin hole 101d, that is, along the fracture starting groove 105. ing. That is, the rod-side bearing metal portion 213a and the cap-side bearing metal portion 213b are preferably substantially semicircular.

  Further, bearing locking grooves 201h and 201i are formed in the one dividing line side of the inner peripheral surface of the crankpin hole 101d, and bearing locking grooves 201h'201i 'are formed in the other dividing line side. As shown in FIG. 6, the bearing locking grooves 201h, 201h ′, 201i, and 201i ′ are preferably cut to a predetermined depth while rotating a groove cutting cutter T arranged to be inscribed in the crank pin hole 101d. It is formed by. The bearing locking grooves 201h, 201h ', 201i, 201i' preferably have an arc shape when viewed in the axial direction of the crankpin hole 101d (see FIGS. 6 and 7).

  The bearing locking grooves 201h, 201h ′, 201i, and 201i ′ extend in the circumferential direction across the dividing line and across the dividing line when viewed in a direction substantially perpendicular to the axis of the crank pin hole 101d. (See FIG. 5B). More specifically, the bearing locking grooves 201h and 201h 'are displaced toward the rod portion 102, and the bearing locking grooves 201i and 201i' are displaced toward the cap portion 103. In other words, out of the bearing locking grooves 201h and 201i arranged substantially in parallel in the axial direction of the crankpin hole 101d, the bearing locking groove 201h is formed to be deviated and arranged on the rod portion 102 side. The locking groove 201i is formed so as to be displaced on the cap portion 103 side. On the other hand, of the bearing locking grooves 201h ′ and 201i ′ arranged in parallel in the axial direction of the crankpin hole 101d, the bearing locking groove 201h ′ is formed to be offset from the rod portion 102 side. The locking groove 201i ′ is formed so as to be displaced from the cap portion 103 side.

  Further, as shown in FIG. 6, two locking claws 213c and 213c ′ are preferably provided on the back surface of both end portions 213a ′ of the substantially semicircular rod-side bearing metal portion 213a. Locking claws 213d and 213d ′ are preferably provided in a protruding manner on the back surface of both end portions 213b ′ of the circular cap side bearing metal portion 213b. The locking claw 213c is formed by bearing locking grooves 201h and 201i formed on the split type connecting rod 200 side, and the locking claw 213c ′ is formed by bearing locking grooves 201h ′ and 201i ′ formed on the divided type connecting rod 200 side. It is locked. Further, the locking claw 213d is formed by bearing locking grooves 201h and 201i formed on the split connecting rod 200 side, and the locking claw 213d ′ is formed by bearing locking grooves 201h ′ and 201i ′ formed on the split connecting rod 200 side. , Respectively.

  More specifically, since the bearing locking grooves 201h, 201h ′, 201i, 201i ′ are offset in the circumferential direction across the dividing line, the locking claws 213c, 213c ′ of the rod side bearing metal portion 213a are The bearing locking grooves 201i and 201i ′ displaced toward the cap portion 103 are locked at the ends of the rod portion 102. The locking claws 213d and 213d 'of the cap-side bearing metal portion 213b are locked at the end portions on the cap portion 103 side of the bearing locking grooves 201h and 201h' displaced to the rod portion 102 side.

  Next, functions and effects of the embodiment of the present invention will be described.

  According to the bearing structure of the present embodiment, the locking claws 213c and 213c ′ of the rod side bearing metal portion 213a are locked at the ends of the bearing locking grooves 201i and 201i ′, and the cap side bearing metal portion 213b is engaged. Since the pawls 213d and 213d ′ are locked at the ends of the bearing locking grooves 201h and 201h ′, the rod-side bearing metal portion 213a and the cap-side bearing metal portion 213b can be prevented from moving in the circumferential direction.

  Here, since the bearing locking grooves 201h, 201h ′, 201i, and 201i ′ are displaced in the circumferential direction, the diameter of the groove cutting cutter T, that is, the diameter of the bearing locking grooves 201h, 201h ′, 201i, and 201i ′ is reduced. Without this, the locking claws 213c, 213c ′, 213d, and 213d ′ can be locked at the ends of the bearing locking grooves 201h, 201h ′, 201i, and 201i ′. Further, it is possible to avoid the problem of stress concentration caused by reducing the diameter of the bearing locking grooves 201h, 201h ', 201i, 201i'. That is, when the necessary depth is secured while reducing the diameter of the groove cutting cutter T, that is, the bearing locking grooves 201h, 201h ′, 201i, 201i ′, the shape of the inner surface of the crank pin hole 101d in the bearing locking groove portion. The change is sudden and the problem of stress concentration is likely to occur. On the other hand, when the diameter of the bearing locking grooves 201h, 201h ′, 201i, 201i ′ is simply increased, the locking claws 213c, 213c ′, 213d, 213d ′ are formed in the bearing locking grooves 201h, 201h ′, 201i, 201i ′. However, in this embodiment, the locking claws 213c, 213c ′, 213d, and 213d ′ are connected to the bearing locking grooves 201h and 201h ′. , 201i, and 201i ′, the problem can be prevented.

  In the present embodiment, the bearing locking grooves are preferably formed in both dividing line portions. However, if the bearing locking grooves in various embodiments of the present invention are formed in any one of the dividing line portions. good. That is, in this embodiment, as shown in FIGS. 6 and 7, the locking claws 213 c and 213 c ′ protrude from both end portions 213 a ′ of the rod side bearing metal portion 213 a, and the cap side bearing metal portion It is assumed that the locking claws 213d and 213d ′ are projected from both ends 213b ′ of 213b. However, a rod-side bearing metal part 213a in which a locking claw (for example, a locking claw 213c) protrudes from only one of both ends 213a ′ and a locking claw (rod-side bearing metal part) only at one of both ends 213b ′. When only the locking claw 213c protrudes at 213a, a cap-side bearing metal part 213b provided with a locking claw 213d) may be used. FIG. 8 is a perspective view of an example of the cap-side bearing metal part 213b in which one locking claw 213d projects from one end of the both end parts 213b '. FIG. 9 is a perspective view of the split connecting rod 200 with the cap-side bearing metal part 213b attached. As shown in FIG. 9, the locking claw 213d of the cap side bearing metal portion 213b is locked by a bearing locking groove 201h that is recessed in the inner peripheral surface of the crankpin hole 101d. When such a cap-side bearing metal portion 213b is actually used, one locking claw 213c protrudes from one of the two end portions 213a ′ so as to be locked by the bearing locking groove 201i. The rod side bearing metal part 213a is also attached together. Therefore, the rod-side bearing metal part 213a and the cap-side bearing metal part 213b can be prevented from rotating in the circumferential direction. As described above, the same effect as that of the split connecting rod 200 described in the present embodiment can be realized without providing the bearing locking grooves 201h ′ and 201i ′.

  In the above case, the features of the split connecting rod 100 described in the first embodiment may be introduced into the split connecting rod 200 of the present embodiment. More specifically, at a position where the bearing locking grooves 201h ′ and 201i ′ are not recessed, that is, at a position on the planned fracture surface facing the bearing locking grooves 201h and 201i on the inner peripheral surface of the crank pin hole 101d. Alternatively, the valley 106 described in Embodiment 1 may be formed.

  According to the present invention, the split type connecting rod of the present invention has an effect that the rotation of the bearing metal can be suppressed with a simple structure, and problems such as seizure can be surely avoided. It is useful as a split type connecting rod.

The front view of the split type connecting rod which concerns on Embodiment 1 of this invention Sectional drawing of the big end part of the split type connecting rod of Embodiment 1 of this invention The figure for demonstrating the angle of the inclination part of the trough part in the fracture | rupture starting groove | channel of the said large end part The figure for demonstrating the opening width of the trough part in the fracture | rupture origin groove | channel of the said big end part The figure which shows the fracture | rupture division | segmentation method of the said big end part Front view of split type connecting rod according to Embodiment 2 of the present invention VV sectional view of the split connecting rod shown in FIG. 5A VI-VI sectional view of the split connecting rod shown in FIG. 5B VII-VII sectional view of the split type connecting rod shown in FIG. 5B The perspective view of an example of the cap side bearing metal part by which the latching claw protruded only in one of the two ends. The perspective view of the split type connecting rod of the state which attached the cap side bearing metal part shown in FIG.

Explanation of symbols

100, 200 Split type connecting rod 101a Rod body 101b Piston pin hole 101c Small end part 101d Crank pin hole 101e Large end part 101f Shoulder part 101g Bolt hole 102 Rod part 103 Cap part 104 Fastening bolt 105 Breaking origin groove 105a Bottom part 105b Inner face 105c Bottom face 106 Valley portion 106a Inclined portion 107 Boundary point 201h, 201h ′, 201i, 201i ′ Bearing locking groove 213 Bearing metal 213a Rod side bearing metal portion 213a ′, 213b ′ End portion 213b Cap side bearing metal portion 213c, 213c ′, 213d 213d 'locking claw

Claims (4)

In the split type connecting rod that grips the crankpin via the bearing having the protrusion,
A first locking groove for locking the first protrusion of the bearing when the bearing rotates forward in the circumferential direction of the crankpin hole;
A second locking groove for locking the second protrusion of the bearing when the bearing rotates in reverse.
The split connecting rod, wherein the first locking groove and the second locking groove are offset from each other in the circumferential direction.   The first locking groove and the second locking groove are disposed so as to straddle both the rod portion and the cap portion when the large end portion is broken and divided into the rod portion and the cap portion. 2. The split connecting rod according to claim 1, wherein the first locking groove is displaced on the rod portion side, and the second locking groove is displaced on the cap portion side.   An engine comprising the split connecting rod according to claim 1.   A vehicle comprising the split type connecting rod according to claim 1.

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