JP4690977B2 - Variable stroke characteristics engine - Google Patents

Description

  In the present invention, a piston and a crankshaft are connected to a control shaft via a variable stroke link mechanism, and the stroke variable link mechanism is operated by an actuator that drives the control shaft, thereby changing the moving stroke of the piston. The present invention relates to an improvement of a variable stroke characteristic engine.

Conventionally, an upper link having one end connected to the piston pin of the piston, a lower link connected to the other end of the upper link and connected to the crank pin of the crankshaft, and one end connected to the lower link, the other 2. Description of the Related Art A variable stroke characteristic engine having a stroke variable link mechanism having a control link whose end is swingably connected to an engine body, and which makes a moving stroke of a piston variable by driving the control link with an actuator is known ( Patent Documents 1 and 2).
JP 2006-177192 A JP-A-9-228858

  By the way, in such an engine, if an actuator that drives the variable stroke link mechanism is provided outside the crankcase that is the engine body, the actuator will protrude greatly outside the engine body, including other auxiliary equipment. Not only does the bulk of the engine increase, but the actuator may interfere with other auxiliary devices, so the degree of freedom of the arrangement of the actuator is reduced. Especially when this engine is used for a vehicle, There is a problem that the tendency is further increased.

  In order to solve such a problem, if the actuator is provided in the engine body, for example, in the crank chamber, the crankcase will protrude greatly outward, leading to an increase in size and cost of the engine body. There is another problem.

  The present invention has been made in view of such a situation, and in particular, to provide a novel variable stroke characteristic engine that enables the housing constituting the main part of the actuator to be greatly reduced in size and solves the above problems. With the goal.

In order to achieve the above object, according to the first aspect of the present invention, a piston and a crankshaft are connected to a control shaft via a variable stroke link mechanism, and the variable stroke link mechanism is controlled by an actuator that drives the control shaft. In a variable stroke characteristic engine that operates and makes the moving stroke of the piston variable,
At least a portion of the housing of the actuator, the fixed to the engine body is characterized in that formed in the bearing member for rotatably supporting the crankshaft.

The engine body includes a cylinder block, including a crankcase (upper block and lower block) for rotatably supporting the crankshaft is coupled integrally with the cylinder block having a cylinder in which the piston is slidably provided.

To achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the bearing member is fixed to a cylinder block constituting the engine body and rotatably supports the crankshaft. It is a bearing cap.

In order to achieve the above object, according to a third aspect of the present invention, in the first or second aspect of the present invention, at least a part of the housing of the actuator is cast into the bearing member. Yes.

In order to achieve the above object, according to a fourth aspect of the present invention, there is provided the actuator according to any one of the first to third aspects, wherein the housing of the actuator is a plurality of bearing members that support the crankshaft. The bearing member is provided on the bearing member avoiding the bearing members at both ends thereof.

To achieve the above object, the invention of claim 5, wherein, in one of the claim 4, the housing of the actuator, as characterized in that it is provided in the center of the bearing member of the engine body in-line four-cylinder engine Yes.

In order to achieve the above object, according to a sixth aspect of the present invention, the actuator housing according to any one of the first to fifth aspects, wherein the actuator housing is fixed to the upper block of the cylinder block. It is characterized by being formed separately from the block.

According to the first aspect of the present invention, at least a part of the housing of the actuator that operates the variable stroke link mechanism is a part of the engine body, that is, a bearing that is fixed to the engine body and rotatably supports the crankshaft. Since it is formed of a member, it is possible to reduce the size of the housing and the number of parts, thereby suppressing an increase in size even though the engine is a variable stroke characteristic type . The at least a portion of the housing of the actuator by forming in the bearing member, it is possible to close the actuator clan click axis, becomes possible to further reduce the size of the engine.

According to the invention of claim 2, wherein a bearing member provided with housing, since it is bearing cap for rotatably supporting the crankshaft, it is easy molding of the housing improves the supporting rigidity of the crankshaft .

According to the third aspect of the present invention, since the housing is cast into the bearing member, the rigidity of the housing can be further increased.

According to the fourth aspect of the present invention, the housing is provided on the bearing member that avoids the bearing members at both ends of the plurality of bearing members, which contributes to further downsizing of the engine.

According to the fifth aspect of the present invention, since the housing is provided in the center bearing member of the engine body of the in-line four-cylinder engine, it contributes to further improvement in the rigidity of the center bearing member to which the largest load is applied. it can.

According to the sixth aspect of the present invention, since the housing is formed separately from the lower block fixed to the upper block, the housing can be freely processed and can be selected as a single product. The degree can be increased, and the assembly to the lower block can be performed compactly and easily.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention shown in the accompanying drawings.

  In this embodiment, the variable stroke characteristic engine of the present invention is used for an automobile.

  1 is a schematic overall perspective view of a variable stroke characteristic engine, FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1, FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 is a sectional view taken along line 4-4 in FIG. 1 (low compression ratio state), FIG. 5 is a sectional view taken along line 5-5 in FIG. 2, and FIG. 6 is a sectional view taken along line 6-6 in FIG. 7 is an enlarged vertical view taken along line 7-7 in FIG. 5, FIG. 8 is a sectional view taken along line 8-8 in FIG. 3, and FIG. 9 is a perspective view taken along arrow 9 in FIG. FIG. 10 is an exploded perspective view of the actuator, and FIG. 11 is a hydraulic circuit diagram of the control system of the actuator.

  1 to 4, a variable stroke characteristic engine E according to the present invention is for an automobile and is placed horizontally in an engine room of an automobile (not shown) (the crankshaft 30 is arranged laterally with respect to the traveling direction of the automobile). ). When the engine E is mounted on a vehicle, as shown in FIG. 2, the cylinder E is slightly tilted backward, that is, its cylinder axis LL is slightly tilted backward with respect to the vertical line.

  The variable stroke characteristic engine E is an in-line four-cylinder OHC type four-cycle engine. The engine body 1 includes a cylinder block 2 in which four cylinders 5 are provided in parallel in the lateral direction, and the cylinder block. The cylinder head 3 is integrally coupled to the two deck surfaces via the gasket 6, the upper block 40 (upper crankcase) is integrally formed at the lower portion of the cylinder block 2, and is integrally coupled to the lower surface thereof. The lower block 41 (lower crankcase) is provided, and the crankcase 4 is formed by the upper block 40 and the lower block 41. A head cover 9 is integrally crowned on the upper surface of the cylinder head 3 via a sealing material 8, and an oil pan 10 is integrally coupled to the lower surface of the lower block 41 (lower crankcase). .

  Pistons 11 are slidably fitted to the four cylinders 5 of the cylinder block 2, and four combustion chambers 12 are provided on the lower surface of the cylinder head 3 facing the top surfaces of the pistons 11. An intake port 14 and an exhaust port 15 communicating with those combustion chambers 12 are formed. An intake valve 16 is provided in the intake port 14 and an exhaust valve 17 is provided in the exhaust port 15 so as to be opened and closed. On the cylinder head 3, a valve operating mechanism 18 for opening and closing the intake valve 16 and the exhaust valve 17 is provided. The valve mechanism 18 swings on an intake side cam shaft 20 and an exhaust side cam shaft 21 that are rotatably supported by the cylinder head 3, and on an intake side and exhaust side rocker shafts 22, 23 provided on the cylinder head 3. The intake side and exhaust side camshafts 20 and 21 and the intake side and exhaust side rocker arms 24 and 25 connected to the intake valve 16 and the exhaust valve 17 so as to be pivotally supported are provided. According to the rotation of the shafts 20 and 21, the intake side and exhaust side rocker arms 24 and 25 are swung against the valve closing force of the valve springs 26 and 27, and the intake valve 16 and the exhaust valve 17 are moved at a predetermined timing. Can open and close.

  As shown in FIG. 2, the intake-side and exhaust-side camshafts 20, 21 are interlocked with a crankshaft 30 described later via a conventionally known timing transmission mechanism 28, and according to the rotation of the crankshaft 30, It is driven at half the rotational speed. The valve mechanism 28 is covered with a head cover 9 that is integrally crowned on the cylinder head 3. The cylinder head 3 is provided with a cylindrical plug insertion cylinder 31 corresponding to the four cylinders, and a spark plug 32 is inserted into the plug insertion cylinder 31.

  The plurality of intake ports 14 corresponding to the four cylinders 5 are opened toward the front surface of the engine body 1, that is, the front side of the vehicle, and an intake manifold 34 of the intake system IN is connected thereto. Since the intake system IN has a conventionally known structure, a detailed description thereof will be omitted.

  A plurality of exhaust ports 15 corresponding to the four cylinders 5 are opened toward the rear surface of the engine body 1, that is, toward the rear side of the vehicle, and an exhaust manifold 35 of the exhaust system EX is connected thereto. Since the exhaust system EX has a conventionally known structure, a detailed description thereof is omitted.

  As shown in FIGS. 3 and 4, the crankcase 4 including the upper block 40 (upper crankcase) at the lower part of the cylinder block 2 and the lower block 41 (lower crankcase) is more forward than the cylinder 5 part of the cylinder block 2. It projects to the (vehicle front) side, and in the crank chamber CC of the projecting portion 36, a stroke variable link mechanism LV (described later) that makes the moving stroke of the piston 11 variable, and a hydraulic actuator AC ( Provided below).

  As shown in FIGS. 2, 3 and 5, 6, a lower block 41 is fixed to the lower surface of the upper block 40 formed integrally with the lower portion of the cylinder block 2 with a plurality of connecting bolts 42, and serves as a bearing cap. The bearing member 54 is fixed with a bearing cap tightening bolt 57.

  The journal shaft 30J of the crankshaft 30 is rotatably supported by a plurality of journal bearing portions 43 formed on the mating surfaces of the upper block 40 and the lower block 41 (see FIG. 8).

  As shown in FIG. 5, the lower block 41 is cast and molded in a closed cross-sectional structure having a square shape in plan view. End bearing members 50 and 51 are provided at the left and right ends thereof, and an intermediate portion thereof is provided at In the center of the left and right intermediate bearing members 52 and 53, a central bearing member 54 (a housing HU described later is integrally formed) is provided as a bearing cap. The journal shaft 30J of the crankshaft 30 is supported.

  As shown in FIGS. 5, 6, and 9, the central bearing member, that is, the bearing cap 54 is cast and formed separately from the lower block 41, and the lower block 41 is formed by a plurality of bearing cap tightening bolts and bolts 56. The bearing cap 54 is also firmly fixed to the lower surface of the upper block 40 by other bearing cap tightening bolts 57. One side portion of the central bearing member, that is, the bearing portion 54A of the crankshaft 30 of the bearing cap 54 that is biased to one side (the front of the engine body 1) is an enlarging portion 58 that has an enlarged vertical width and is thick. This enormous portion 58 is provided with a housing HU for a hydraulic actuator AC, which will be described in detail later.

  Here, the housing HU may be cast and formed in the enormous portion 58 of the bearing cap 54.

  Next, returning to FIGS. 3 and 4, the structure of the variable stroke link mechanism LV that makes the moving stroke of the piston 11 variable will be described. A crank that is rotatably supported on the mating surface of the upper block 40 and the lower block 41. An intermediate portion of a triangular lower link 60 is pivotally connected to the plurality of crank pins 30P of the shaft 30 so as to be swingable. One end (upper end) of the lower link 60 is pivotally connected to the lower end (large end) of an upper link (connecting rod) 61 pivotally connected to the piston pin 13 of the piston 11 via a first connecting pin 62. The upper end of the control link 63 is pivotally connected to the other end (lower end) of each lower link 60 via the second connecting pin 64. The control link 63 extends downward, and an eccentric pin 65P of a control shaft 65 (detailed later) is pivotally connected to the lower end of the control link 63. The control shaft 65 is driven within a predetermined angle range (about 90 degrees) by a hydraulic actuator AC (described in detail later), and the control link 63 is driven to swing by the displacement of the eccentric pin 65P. Specifically, the control shaft 65 rotates between a first position shown in FIG. 3 (the eccentric pin 65P is a lower position) and a second position shown in FIG. 4 (the eccentric pin 65P is a left position). Is possible. In the first position shown in FIG. 3, the eccentric pin 65P of the control shaft 65 is positioned below, so that the control link 63 is pulled down and the lower link 60 swings clockwise around the crank pin 30P of the crankshaft 30. As a result, the upper link 61 is pushed up, and the position of the piston 11 becomes higher than the cylinder 5, and the engine E enters a high compression ratio state. On the other hand, in the second position shown in FIG. 4, the eccentric pin 65P of the control shaft 65 is located to the left (higher than the first position), so that the control link 63 is pushed up to lower link 60. Swings counterclockwise around the crankpin 30P of the crankshaft 30, the upper link 61 is pushed down, and the position of the piston 11 is lowered to a high position relative to the cylinder 5, and the engine E is in a low compression ratio state. As described above, by the rotation control of the control shaft 65, the control link 63 swings, the motion constraint condition of the lower link 60 changes, and the stroke characteristics including the top dead center position of the piston 11 change. It becomes possible to arbitrarily control the compression ratio of the engine E.

  Thus, the upper link 60, the first connecting pin 62, the lower link 60, the second connecting pin 64, and the control link 63 constitute a variable stroke link mechanism LV according to the present invention.

  As shown in FIGS. 6, 7, 9, and 10, the control shaft 65 that is connected to the control link 63 and operates the stroke variable link mechanism LV includes a plurality of journal shafts 65 </ b> J and eccentric pins 65 </ b> P, like the crankshaft 30. Are alternately connected via the arms A to form a crank shape, and a cylindrical vane shaft 66 is integrally provided between the eccentric pins 65P in the center in the axial direction. The control shaft 65 is biased to one side of the lower block 41 (the front side of the engine body 1), and the journal shaft 65J is a bearing that is fixed to the lower block 41 and a plurality of connecting bolts 68 on the lower surface thereof. It is rotatably supported between the block 70. The bearing block 70 includes a vertical frame 71 that extends in the axial direction of the control shaft 65, a plurality of bearing walls 72 that stand up together with the vertical frame 71, and a central housing receiving portion 73. A bearing between the mating surfaces of the upper surfaces of the plurality of bearing walls 72 and the lower surfaces of the bearing walls 50a, 51a, 52a, 53a extended from the bearing members 50, 51, 52, 53 of the lower block 40 is provided. The journal shaft 65J of the control shaft 65 is rotatably supported by the portion.

  As will be described later, the lower portion of the housing HU provided on the central bearing member 54 is fixedly supported by a plurality of bolts 74 on the central housing receiving portion 73 formed in the bearing block 70 (see FIG. 6).

  As shown in FIGS. 6 and 7, the hydraulic actuator AC that drives the control shaft 65 is provided in the crank chamber CC of the engine body 1, and the housing HU that accommodates and supports the hydraulic drive unit includes the central bearing member. 54 (fixed integrally with the upper block 40 and the lower block 41) is provided in the enlarging portion 58 on one side. The housing HU is formed with a short cylindrical vane chamber 80 whose both end faces are open, and a vane shaft 66 at the center of the control shaft 65 is passed through and accommodated in the vane chamber 80. The housing HU is rotatably supported by left and right vane bearings 81 and 82 which are other housings fixed with a plurality of bolts 83 on both sides of the housing HU, and the open side surface of the vane chamber 80 is closed by the left and right vane bearings 81 and 82. A pair of fan-shaped vane oil chambers 86 are formed between the inner peripheral surface of the vane chamber 20 and the vane shaft 66 with a phase difference of about 180 °, and the vane shafts are formed in the vane oil chambers 86. A pair of vanes 87 projecting integrally from the outer peripheral surface of the central portion of 66 is accommodated, and each vane 87 is oil-tightly divided into two control oil chambers in a fan-shaped vane oil chamber 86. By supplying and discharging hydraulic oil from a hydraulic circuit, which will be described later, to and from the two control oil chambers, the vane shaft 66, that is, the control shaft 65 can be reciprocated within a predetermined angle range.

  As described above, the housing HC of the hydraulic actuator AC that drives the control shaft 65 is compact using the central bearing member of the lower block 41 (formed separately from the lower block 41 and fixed thereto). In addition, the number of parts can be reduced, the volume occupied by the housing HC in the crank chamber CC can be reduced, and the bulk of the crankcase can be prevented from increasing.

  As shown in FIGS. 5, 7, and 9, the upper surface of the housing HU formed on the central bearing member 54 is flat and spreads in a dovetail shape from the bearing portion 54 </ b> A of the crankshaft 30 toward the end on the housing HU side. As shown in FIG. 7, the width D1 of the mounting surface 90 in the direction of the control shaft 65 is wider than the width D2 of the housing HU. A valve unit 92 of the hydraulic control circuit of the actuator AC is fixedly supported by a plurality of bolts 91, and this valve unit 92 penetrates the wall surface of the cylinder block 2 and is exposed on the upper surface thereof (FIG. 1). reference). As a result, the valve unit 92 can be firmly fixed on the mounting surface of the housing HU. The valve unit 92 is on the mounting wall surface of the cylinder block 2 and is open on all four sides. The switching operation and maintenance of the type vane actuator AC are facilitated.

  Next, a hydraulic circuit of a hydraulic actuator AC that drives and controls the stroke variable link mechanism LV will be described with reference to FIG.

  As described above, the two control oil chambers that divide the inside of the pair of fan-shaped vane oil chambers 86 formed by the vane shaft 66 of the control shaft 65 and the housing HU by the vanes 87 are connected to the oil tank T via the hydraulic circuit. An oil pump P driven by a motor M, a check valve C, an accumulator A, and an electromagnetic switching valve V are connected to the hydraulic circuit. An oil tank T, a motor M, an oil pump P, a check valve C, and an accumulator A constitute a hydraulic pressure supply device S, which is provided at an appropriate position of the engine body 1, and an electromagnetic switching valve V is provided inside the valve unit 92 described above. Is provided. The hydraulic pressure supply device S and the electromagnetic switching valve V are connected by two pipes P1 and P2, and the electromagnetic switching valve V and the hydraulic actuator AC are connected by two pipes P3 and P4. Therefore, in FIG. 11, the vane 87 is pushed by the hydraulic pressure generated by the oil pump P that switches the electromagnetic switching valve V to the left, and the control shaft 65 rotates counterclockwise. Conversely, the electromagnetic switching valve V is moved to the right. The phase of the eccentric pin 65P of the control shaft 65 changes when the vane 87 is pushed by the hydraulic pressure generated by the oil pump P to be switched and the control shaft 65 rotates clockwise. The control link 63 of the stroke variable link mechanism LV is pivotally connected to the eccentric pin 65P of the control shaft 65 so that the control pin 65 is driven (about 90 °), and the eccentric pin 65P of the control shaft 65 is driven. As described above, the stroke variable link mechanism LV is operated by the phase change.

  By the way, according to this embodiment, the housing HU of the hydraulic actuator AC that operates the variable stroke link mechanism LV is provided on the central bearing member 54 as a bearing cap of the crankshaft 30 that is a part of the engine body 1. Therefore, compared with a conventional housing provided separately from the engine main body, the number of parts can be reduced and the housing can be formed compactly. Even if the housing HC is provided in the crank chamber CC, the crank chamber CC Thus, the increase in size of the engine E can be suppressed without increasing the bulk. In particular, by providing a housing HU of the hydraulic actuator AC on the central bearing member 54 that is a bearing cap of the crankshaft 30, the actuator AC can be disposed close to the crankshaft 30, and the engine E can be further reduced in size. And the support rigidity of the crankshaft 30 can be increased.

  Further, the portion of the central bearing member 54 as the bearing cap excluding the housing HU is formed of aluminum alloy, and the housing HU of the actuator AC forming the vane chamber 80 is formed of iron as a material having higher rigidity. When the housing HU is cast into the bearing cap 54, the rigidity and weight reduction of the housing HU can be achieved in a balanced manner. In this case, the rigidity is higher than when all of the bearing cap 54 is made of an aluminum alloy, and the weight can be reduced as compared with the case where all of the bearing cap is made of iron.

  Furthermore, the housing HU of the actuator AC is provided in the central bearing member 54 that avoids the bearing members 50 and 51 at both ends of the plurality of bearing members 50 to 54 that support the crankshaft 30. This contributes to further downsizing of the engine.

  Furthermore, since the housing HU of the actuator AC is provided in the central bearing member 54 of the engine body 1 of the in-line four-cylinder engine E, it can contribute to further improvement in the rigidity of the central bearing member 54 where the largest load is applied. .

Furthermore, since the housing HU of the actuator AC is formed separately from the lower block 41 fixed to the upper block 40 of the cylinder block 2, the housing HU can be freely selected in addition to the freedom of selection of the material. As a result, the degree of freedom in processing increases, and the assembly to the lower block 41 can be performed compactly and easily.
As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above embodiment, the case where the present invention is a variable compression ratio engine that changes the top dead position of the piston by changing the phase of the eccentric pin of the control shaft has been described. For example, the position and stroke at each stroke can be applied to the intake, compression, explosion, and exhaust of the piston by controlling the rotation of the control shaft at half the speed of the crankshaft by the actuator. The present invention can also be applied to a device whose length can be changed. Moreover, although the case where the vane type hydraulic actuator is used as the actuator has been described in the above embodiment, other actuators such as an electric actuator may be used instead. Further, in the above embodiment, the bearing cap provided with the housing is formed separately from the lower block, but the bearing cap provided with the housing may be formed integrally with the lower block.

Schematic overall perspective view of engine with variable stroke characteristics 2 arrow view of FIG. Sectional view along line 3-3 in FIG. 1 (high compression ratio state) Sectional view along line 4-4 in FIG. 1 (low compression ratio state) Sectional view along line 5-5 in FIG. Cross-sectional view along line 6-6 in FIG. Enlarged vertical view along line 7-7 in FIG. Sectional view along line 8-8 in FIG. 9 perspective view of FIG. Exploded perspective view of actuator Hydraulic circuit diagram of actuator control system

1 .... Engine body 2 .... Cylinder block 11 ... Piston 30 ... Crankshaft 40 ... Upper block 41・ ・ ・ ・ ・ ・ ・ Lower block 50 ・ ・ ・ ・ ・ ・ ・ Bearing member (end bearing member)
51 ····· Bearing member (end bearing member)
52 ····· Bearing member (intermediate bearing member)
53 ···· Bearing member (intermediate bearing member)
54 .. ・ Bearing member (central bearing member)
65 ... Control axis AC ... Actuator (hydraulic actuator)
LV .... Stroke variable link mechanism HU ... Housing

Claims (6)

A piston (11) and a crankshaft (30) are connected to a control shaft (65) via a stroke variable link mechanism (LV), and the stroke variable link is driven by an actuator (AC) that drives the control shaft (65). In the variable stroke characteristic engine that operates the mechanism (LV) to change the moving stroke of the piston (11),
At least a portion of the housing (HU) of the actuator (AC), wherein the formed in the engine body fixed to the crank shaft (1) bearing member for rotatably supporting the (30) (54) , stroke characteristic variable engine. It said bearing member (54) is fixed to the cylinder block (2) forming the engine body (1), characterized in that it is a bearing cap for supporting the crank shaft (30) rotatably, claim 1 stroke characteristic variable engine according. The variable stroke characteristic engine according to claim 1 or 2 , wherein at least a part of the housing (HU) of the actuator (AC) is cast in the bearing member (54). The housing (HU) of the actuator (AC) is a bearing member (a bearing member (50, 51) that avoids the bearing members (50, 51) at both ends of the plurality of bearing members (50-54) that support the crankshaft (30). 54) The variable stroke characteristic engine according to any one of claims 1 to 3 , wherein the engine is provided in (54). The variable stroke characteristic engine according to claim 4 , wherein the housing (HU) of the actuator (AC) is provided on a bearing member (54) in the center of the engine body (1) of the in-line four-cylinder engine. The housing (HU) of the actuator (AC) is formed separately from the lower block (41) fixed to the upper block (40) of the cylinder block (2). The stroke characteristic variable engine according to any one of 1 to 5 .

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