Cylinder block

Abstract

To provide a cylinder block which enables easy replacement of a belt driving water pump with an electric water pump.SOLUTION: A horizontally long outlet passage 11 is open on a front surface of a cylinder block 1 and a vertically long outlet passage 7 is connected to a back part of the horizontally long outlet passage 11 through a communication part 29. An electric water pump 17 is disposed at a pump pedestal 10 of the cylinder block 1 through a timing chain cover 8. The horizontally long outlet passage 11 has a straight passage part 11b and an inclined passage part 11c. A suction port 19 of the water pump 17 is arranged concentrically with the inclined passage part 11c. A guide member 30 which guides a coolant to the inclined passage part 11c is attached to the horizontally long outlet passage 11. The communication part 29 is formed by cutting a dummy wall part 31 which existed during casting. The straight passage part 11b is located at a position corresponding to a mechanical water pump and the cylinder block 1 enables use of the electric water pump 17 with a slight design change.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cylinder block having an outlet passage for cooling water. [Background technology]

[0002] Engines (internal combustion engines) are cooled by coolant, which is circulated by a water pump. Many proposals have been made for engine cooling structures from various perspectives.

[0003] As an example, Patent Document 1 discloses that when a cylinder block is provided with a cooling water inlet passage and a cooling water jacket, the two are cast so that they are separated by a film-like portion, and then the film-like portion is removed by drilling to form a flow straightening guide portion at the back of the cooling water inlet passage, and part of the cooling water is directed by the flow straightening guide portion to the exhaust side portion of the cooling water jacket, thereby accurately cooling the exhaust side portion where the temperature is high.

[0004] Furthermore, water pumps come in two types: belt-driven, which are driven by an accessory drive belt, and electric, which are driven by a motor. Patent Document 2 discloses that in an electric water pump, a straightening plate is provided inside the discharge port to control the flow of cooling water. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-206366 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-063900 Summary of the Invention [Problem to be solved by the invention]

[0006] When the water pump is driven by an accessory drive belt, the rotation axis of the impeller is parallel to the crankshaft, so the water pump is placed on the outer surface of the timing chain cover or on the side of the cylinder block.

[0007] On the other hand, if the water pump is electric, its location can be set arbitrarily, but when replacing a mechanical water pump with an electric one, there are cases where design changes should be kept to a minimum and changes to the structure of the cylinder block, etc., should be avoided as much as possible.

[0008] However, because belt-driven water pumps and electric water pumps have different specifications, such as size, there are cases where the design of the cylinder block must be changed. For example, if the outlet passage opening to the cylinder block remains the same as when the belt-driven water pump was used, the water pump's performance will be affected when replaced with an electric water pump. Intake port This can cause misalignment between the outlet passage of the cylinder block and the engine, which can require a design change to accommodate an electric water pump.

[0009] In this case, it would be sufficient to change the position of the outlet passage in the cylinder block, but changing the position of the outlet passage would change its relationship with the cooling water passage formed in the cylinder block, which could lead to problems such as making casting and machining more complicated and increasing the size of the cylinder block.

[0010] The present invention was made against the background of the above circumstances, and aims to minimize the design changes of the cylinder block for engines of different specifications. be. [Means for solving the problem]

[0011] The present invention relates to a cylinder block to which a water pump is fixed directly or via a timing chain cover, and the cylinder block comprises: "The water pump is directly or through the timing chain cover. An outlet passage for sending cooling water to the water pump is opened on the surface where the two parts overlap. A cylinder block, before The outlet passage extends over the entire length from the opening surface to the bottom surface. Direct Road section and The opening surface is in communication with the straight path portion while being misaligned from the straight path portion. a sloped path portion extending to a mid-depth portion of the straight path portion; and an opening surface of the outlet passage is oval or elliptical because the opening surface of the straight path portion and the inclined path portion are misaligned. Furthermore, when viewed from a direction perpendicular to the opening surface, a virtual circle of the opening surface of the inclined road portion partially overlaps with the straight road portion. " The structure is as follows.

[0012] The present invention can be embodied in various ways. For example, claim 2 states: "A guide member is attached to the outlet passage to guide the cooling water from the innermost portion of the straight path portion to the inclined path portion." The following configuration is adopted.

[0013] When the guide means is provided as in claim 2, it is preferable that the guide means is made of synthetic resin and a flange is formed, and the flange is sandwiched between the cylinder block and the timing chain cover, or between the cylinder block and the water pump. [Effects of the Invention]

[0014] In the present invention, the outlet passage of the cylinder block is a straight passage portion. The opening surfaces of the ramp and the gate are not aligned. slope section Niu Water pump suction port but Concentrically overlapping and The cooling water changes direction midway from the deepest part of the straight section, reaches the opening of the inclined section, and flows smoothly to the suction port of the water pump.

[0015] The straight portion of the outlet passage is provided inside the cylinder block and aligned with the flow path, and is positioned to facilitate casting and machining. The suction port can be arranged concentrically with the opening of the inclined section or with the straight section. Therefore, it is possible to ensure smooth flow of cooling water, while also facilitating the casting and machining of the cylinder block and allowing greater freedom in the placement of the water pump.

[0016] As a result, for engines with different specifications, it is possible to reduce costs and stabilize quality across an entire group of engines of multiple models by making only minor changes to the design of the cylinder block.

[0017] When a guide member is provided as in claim 2, From straight section to inclined section In this case, as described above, if a flange is provided on the guide member and the flange is sandwiched between the cylinder block and the timing chain cover or water pump, the flange of the guide member can function as a water seal, eliminating the need for gaskets that were previously used, contributing to reduced costs and assembly work. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of an embodiment. [Figure 2] FIG. 4 is a longitudinal side view of the main part, and a cross-sectional view taken along line II-II in FIG. 3(A). [Figure 3] 3A is a cross-sectional plan view of the main part, and FIG. 3B is a perspective view of a guide member. [Figure 4] 10A to 10C are diagrams illustrating a process of removing a dummy wall portion. [Figure 5] This is an example of a guide member when a belt-driven water pump is used. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, an embodiment of the present invention will be described with reference to the drawings. Hereinafter, the terms "front-rear" and "left-right" will be used to specify directions, with the front-rear direction being the crankshaft axis direction, with the side where the timing chain is located being the front and the side where the transmission is located being the rear. The left-right direction is a direction perpendicular to the crankshaft axis and the cylinder bore axis. The up-down direction is the cylinder bore axis direction, which in this embodiment is the same as the vertical direction. Directions are clearly indicated in Figure 1, etc., just to be clear.

[0020] (1) Overview This embodiment is applied to a cylinder block 1 of a three-cylinder engine for an automobile, and Fig. 1 shows the entire cylinder block 1. The cylinder block 1 has, from front to back, three cylinder bores 2 to 4, numbered first to third, and the group of cylinder bores 2 to 4 is surrounded by a loop-shaped water jacket 5. On both sides of the group of water jackets 5, groups of tapped holes 6 for head bolts are opened.

[0021] Furthermore, a vertically elongated outlet passage 7 that communicates with a downward-opening return water passage provided in a cylinder head (not shown) opens upward in a region of the cylinder block 1 on the intake side across the water jackets 2 to 4 and to the side of the first and second cylinder bores 2, 3. The vertically elongated outlet passage 7 is long from front to back in plan view.

[0022] On the other hand, a pump base 10 is formed on the front surface of the cylinder block 1, on which the pump housing portion 9 (see Figures 2 and 3(A)) of the timing chain cover 8 overlaps, and a horizontally elongated outlet passage 11, which is long in the front-to-rear direction and communicates with the vertically elongated outlet passage 7, opens into the pump base 10. This horizontally elongated outlet passage 11 corresponds to the outlet passage described in the claims. As clearly shown in Figure 1, the opening surface of the horizontally elongated outlet passage 11 is formed in an oval shape long in the left-to-right direction, and a step portion 11a is formed around the entire periphery of the opening edge.

[0023] A wall 12 is formed on the front surface of the cylinder block 1, and the edge of the timing chain cover 8 overlaps with the wall 12. The timing chain cover 8 is fixed mainly to the wall 12 with a group of bolts 12a (see Figure 2). The wall 12 on the exhaust side is continuous with the pump base 10. Needless to say, the timing chain cover 8 also overlaps with the front surface of the cylinder head.

[0024] As shown in Figure 1, an oil separator chamber 13 for collecting oil from blow-by gas opens on the intake side of the cylinder block 1, overlapping the vertically elongated outlet passage 7 in a plan view. The oil separator chamber 13 is generally trapezoidal in a side view, and as shown in Figure 2, a vent hole 14 that communicates with the crankcase opens at its bottom. The oil separator chamber 13 is closed with a lid (not shown), and a PCV hose is connected to a cylindrical port provided in the lid.

[0025] As shown in Fig. 1, a front bearing portion 15, which is overlapped from below by a front crank cap (not shown), is provided at the lower end of the front portion of the cylinder block 1. In Fig. 1, reference numeral 16 denotes a bracket portion to which a starter motor is attached.

[0026] (2) Details of the main parts 2 and 3 show the state in which the water pump 17 is provided. As described above, in this embodiment, the pump housing portion 9 is formed in the timing chain cover 8, and therefore the timing chain cover 8 also constitutes a part of the water pump 17.

[0027] To be precise, the pump housing part 9 of the timing chain cover 8 has a forward opening. A pump chamber (vortex chamber) 18 and a suction port 19 communicating with the pump chamber 18 and the horizontally elongated outlet passage 11 are formed, and an impeller 20 is rotatably disposed in the pump chamber 18.

[0028] The impeller 20 has a main shaft 21 that protrudes forward, and the main shaft 21 is rotatably held via bearings (not shown) in a pump cover 22 that is fixed to the pump housing 9 with bolts. A rotor 23 made of a permanent magnet is fixed to the main shaft 21, and the rotor 23 is surrounded by a group of electromagnets (coils) 24 arranged inside the pump cover 22. Therefore, the water pump 17 of this embodiment is electrically driven. The main shaft 21 is water-sealed by a seal plate 27. As shown in FIG. 3(A), a control unit 22a incorporating a circuit board and the like is provided at the rear of the pump cover 22.

[0029] 1, a horizontally elongated inlet passage 25 into which cooling water discharged from the water pump 17 flows is opened at a portion of the pump base 10 in the cylinder block 1 above the horizontally elongated outlet passage 11, and the innermost portion of the horizontally elongated inlet passage 25 is connected to a vertically elongated inlet passage 26 that continues to the water jacket 5. Therefore, the cooling water flows into the water jacket 5 from the vertically elongated inlet passage 26.

[0030] 2, a relay passage 28 is formed in the timing chain cover 8, connecting the discharge portion of the pump chamber 18 with the vertically elongated inlet passage 26 of the cylinder block 1. The cooling water that reaches the water jacket 5 flows into the water jacket of the cylinder head through a water leg opened in the gasket.

[0031] In the illustrated example, the cooling water flows from the water jacket 5 of the cylinder block 1 to the water jacket of the cylinder head, but a two-system cooling system can also be used in which when the temperature of the cooling water (engine temperature) is low, all (or most) of the cooling water flows into the water jacket of the cylinder head, and when the temperature of the cooling water rises to a predetermined temperature, the cooling water also flows into the water jacket 5 of the cylinder block 1. In this case, the vertical inlet passage 26 and the water jacket 5 can be separated by a wall, and a control valve such as a thermo valve can be installed on the wall.

[0032] As shown in FIG. 2, the vertically elongated outlet passage 7 is deeper at the front side to avoid the oil separator chamber 13, and as can be seen from FIGS. 2 and 3, the inner end portion of the deep portion (bottom portion) of the horizontally elongated outlet passage 11, which is at the top and close to the cylinder bore 2, is connected to the lower end portion 7a of the vertically elongated outlet passage 7 by a communication portion 29.

[0033] 3, the horizontally elongated outlet passage 11 is composed of a straight section 11b extending from the bottom surface where the communication section 29 opens to the opening surface of the pump base 10, and a slanted section 11c extending to the front and rear midpoints of the straight section 11b while opening to the pump base 10. The opening surface of , left and right directions with respect to the straight path portion 11b Misalignment are. Therefore, As described above, the opening surface of the horizontally elongated outlet passage 11 is formed in an oval shape with its left and right sides longer than the other (it may also be an oval shape with its left and right sides longer than the other). The inclined path portion 11c branches off from the straight path portion 11b at a depth position approximately midway between the front and rear, but the branching position can be set arbitrarily.

[0034] To be precise, the straight passage portion 11b is oriented perpendicular to the pump base 10, and the inclined passage portion 11c is inclined with respect to the perpendicular to the pump base 10 in a plan cross-sectional view. Therefore, the horizontally elongated outlet passage 11 is funnel-shaped.

[0035] As shown in Figures 2 and 3(B), the pump housing portion 9 of the timing chain cover 8, which constitutes the water pump 17, has an intake port 19 that communicates with the pump chamber 18, and the intake port 19 is arranged concentrically with the opening surface of the inclined portion 11c of the horizontal outlet passage 11.

[0036] Therefore, a guide member 30 made of synthetic resin is attached to the opening of the horizontally elongated outlet passage 11, and an inclined guide portion 30a that guides the communication portion 29 from the straight path portion 11b to the inclined path portion 11c is formed on the guide member 30. The guide member 30 is formed with a flange 30b that fits into a step portion 11a formed on the opening of the horizontally elongated outlet passage 11, and a wall portion 30c that connects the free end of the inclined guide portion 30a to the flange 30b. 3(B) is a line showing an imaginary circle of the opening surface of the inclined road section 11c, and as is clear from this imaginary line 11d, a part of the opening surface of the inclined road section 11c extends into the straight road section 11b when viewed in the front-rear direction. In other words, a part of the opening surface of the inclined road section 11c overlaps with the straight road section 11b when viewed in the front-rear direction.

[0037] (3) Summary Now, the cylinder block 1 is an aluminum casting, and casting is performed by pouring molten metal into a mold (sand mold), with the cavity of the mold becoming the wall of the cylinder block 1. If the wall has a complex shape, it may be preferable for the cavities of the mold to be interconnected in order to improve the flow of the molten metal.

[0038] On the other hand, the hollow portion of the cylinder block 1 becomes the core in the mold, but if the shape of the core becomes too complicated, it can be time-consuming to manufacture, difficult to manufacture in the first place, or prone to breakage or damage.To address this issue, the core is divided into multiple pieces and butted together, but if the butting is imperfect, problems such as burrs can form, which can easily cause problems in terms of precision and quality.

[0039] These problems can be solved by forming dummy portions in the areas that should be hollow in the cylinder block 1 during casting, and then removing the dummy portions by machining after casting. This improves the flow of molten metal in the mold, simplifies the manufacture of cores (molds), and improves the quality and yield of castings.

[0040] From this perspective, in the cylinder block 1 of this embodiment, as shown in Figure 4, what should become the communicating portion 29 in the cylinder block 1 is formed as a dummy wall portion 31 at the casting stage, and after casting, this is cut away with an end mill 32 (or drill) inserted into the straight path portion 11b from the outside of the pump base 10 to open the communicating portion 29.

[0041] In this case, the shape and position of the vertically elongated outlet passage 7 are restricted by its relationship with the cylinder head and its relationship with the water jacket 5, and accordingly, the position of the dummy wall 31 is set as close as possible to the water jacket 5 as possible, and accordingly, the preferred position of the horizontally elongated outlet passage 11 is also determined.

[0042] In the case where the water pump is a belt-driven type driven by an accessory drive belt, the horizontally elongated outlet passage 11 is formed as a simple straight path, and the suction port 19 is formed as a straight path. Concentrically with the straight path portion 11b Therefore, the dummy wall portion 31 can be removed without any problem by using the end mill 32 by utilizing the horizontally elongated outlet passage 11 having a simple straight structure. However, in the case of the electric water pump 17, due to a problem in the specifications, the suction port 19 may be shifted forward compared to the case of a belt-driven water pump.

[0043] In this regard, it could be said that it would be sufficient to form the horizontally elongated outlet passage 11 as a simple straight passage and shift its position, but doing so would shift the position of the communication portion 29 forward, which would require redesigning the vertically elongated outlet passage 7, which would require design changes to the cylinder head as well, resulting in problems such as a great deal of work and an increase in the size of the cylinder block 1 and cylinder head.In addition, there is a concern that a change in the position of the dummy wall portion 31 could cause casting defects, and it is expected that it would be difficult to shift the horizontally elongated outlet passage 11.

[0044] Therefore, in this embodiment, the horizontally elongated outlet passage 11 is divided into a straight passage portion 11b that is easy to cast and is compatible with a belt-driven water pump, and a slanted passage portion 11c that is compatible with an electric water pump 17. This allows the electric water pump 17 to be applied while maintaining a rational structure of the vertically elongated outlet passage 7 and the dummy wall portion 31.

[0045] In the horizontally elongated outlet passage 11, the flow path of the cooling water is L-shaped, but the straight path section 11b and the inclined path section 11c intersect at an obtuse angle, so the cooling water changes direction smoothly from the straight path section 11a and flows into the suction port 19 (when the suction port 30 is pressurized (pushed) from the communicating section 29, the cooling water flows in a straight line, but since the cooling water is sucked (pulled) toward the suction port 19, the cooling water flow changes direction smoothly with almost no straight line movement).

[0046] Furthermore, providing a guide member 30 that changes the direction of the cooling water flow from the straight path portion 11b to the inclined path portion 11c, as in the embodiment, promotes the smoothness of the cooling water flow, which is particularly suitable for suppressing pressure loss. Also, because the flange 30b of the guide member 30 can function as a sealant, there is no need to separately provide gaskets for water sealing (O-rings, liquid gaskets, etc.), which has the advantage of simplifying the structure.

[0047] In the illustrated example, the step 11a into which the flange 30b of the guide member 30 is fitted is formed on the pump seat 10 of the cylinder block 1, but the step 11a may also be formed on the timing chain cover 8.

[0048] In the illustrated example, an electric water pump 17 is installed, but a belt-driven water pump can also be installed. That is, one type of cylinder block 1 can be used for both the engine of the belt-driven water pump and the engine of the electric water pump 17. In this case, the suction port of the water pump may be connected to either the inclined path portion 11c or the straight path portion 11b. When connected to the straight path portion 11b, as shown in FIG. 5, a partition wall 30d that blocks the inclined path portion 11c can be provided in the guide member 30.

[0049] Although the preferred embodiment of the present invention has been described above, the present invention can be embodied in various other ways. For example, the water pump can be directly attached to the pump base of the cylinder block. The water pump can also be attached to the exhaust side or intake side of the cylinder block. [Industrial Applicability]

[0050] The present invention can be embodied in an engine cylinder block, and is therefore industrially applicable. [Explanation of symbols]

[0051] 1 Cylinder block 2~4 cylinder bores 5 Water Jacket 7 Vertical exit passage 8 Timing chain cover 9 Pump housing 10 Pump base 11 Horizontal exit passage 11a Stepped section 11b Straight section 11c Slope section 17 Water Pump 18 Pump Room 19 Intake port 20 impeller 21 Main shaft (rotating axis) 22 Pump cover 25 Horizontal entrance passage 26 Vertical entrance passage 29 Communication section 30 Guide member 30a Inclined guide section 30b flange 30c wall 31 Dummy wall 32 End mills as an example of cutting tools

Claims

1. A cylinder block in which an outlet passage for supplying cooling water to the water pump opens on a surface on which the water pump directly overlaps or on which a timing chain cover overlaps, the outlet passage has a straight path portion extending over the entire length from the opening surface to the bottom surface, and a slanted path portion that is integrally connected to the straight path portion and reaches a mid-depth portion of the straight path portion with its opening surface offset from the straight path portion, and the opening surface of the outlet passage is oval or elliptical because the opening surface of the straight path portion and the slanted path portion are offset from each other; When viewed from a direction perpendicular to the opening surface, a virtual circle of the opening surface of the inclined path portion partially overlaps with the straight path portion. Cylinder block.

2. A guide member is attached to the outlet passage to guide the cooling water from the deepest part of the straight path portion to the inclined path portion.

2. The cylinder block according to claim 1.

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