Damping device cooling structure for internal combustion engine

Abstract

A disc-shaped damper (5) is attached to the front end of a crankshaft (4) of an internal combustion engine, and is covered by a damper cover (11) having a cup-shaped portion (12). The cup-shaped portion (12) has an air inlet (21) for taking in air into the cup-shaped portion (12) by pumping action accompanying rotation of the damper (5), and an air outlet (22) for discharging heated air. The air inlet (21) and the air outlet (22) are offset from each other in the axial direction of the crankshaft (4), and air flowing in from the air inlet (21) is discharged from the air outlet (22) after at least one revolution. Air flows around the entire circumference of the damper (5), so effective cooling can be performed.

Description

Technical Field

[0001] The present invention relates to a cooling structure that uses external air to cool a disc-shaped shock absorber (torsional shock absorber) mounted at the front end of the crankshaft of an internal combustion engine. Background Technology

[0002] Sometimes, a disc-shaped shock absorber is installed at the front end of the crankshaft of an internal combustion engine. This shock absorber is configured to connect the inner circumferential portion of the crankshaft to an outer circumferential portion with appropriate mass via an elastic material layer (rubber layer). This shock absorber is used to reduce torsional vibrations of the crankshaft and is sometimes configured as a crankshaft pulley around which a belt is wound.

[0003] The rubber layer of this type of shock absorber is prone to deterioration due to heat, so it is preferable to have a certain cooling structure. Patent Document 1 discloses a cooling structure in which vent holes serving as air inlets and vent holes serving as air outlets are formed on the front surface of the cover that covers the timing belt pulley, respectively, at a position 180° apart from each other on the pulley, so that air flows into the cover as the pulley rotates.

[0004] However, in this current cooling configuration, the vent hole serving as the air inlet and the vent hole serving as the air outlet, located along the crankshaft axis, are on the same plane. Air flowing in from the vent hole (air inlet) travels along the front end face of the pulley and swirls 180° before exiting from the vent hole (air outlet). In other words, the airflow merely flows near the end face of the pulley without completely circling it, failing to effectively cool the pulley.

[0005] Patent Document 1: Japanese Utility Model Application Publication No. 59-79526 Summary of the Invention

[0006] Regarding the shock absorber cooling structure of the internal combustion engine involved in this invention, in an internal combustion engine in which a disc-shaped shock absorber is mounted on a rotating shaft protruding from the end face of the internal combustion engine body and a cover is provided to cover the shock absorber, the cover is provided with an air inlet for guiding air into the space inside the cover by the action of a pump accompanying the rotation of the shock absorber and an air outlet for discharging air from the space, the air inlet and the air outlet being offset from each other in the axial direction of the crankshaft.

[0007] By offsetting the air inlet and air outlet axially relative to each other on the crankshaft, the air drawn in from the air inlet flows spirally around the shock absorber through the pumping action accompanying the shock absorber's rotation, and is discharged from the air outlet after at least one revolution. This achieves effective cooling of the shock absorber. Attached Figure Description

[0008] Figure 1This is a side view of the front end of an internal combustion engine having a shock absorber cooling structure according to one embodiment.

[0009] Figure 2 This is a front view of the front end of an internal combustion engine with a shock absorber cover.

[0010] Figure 3 From Figure 2 A bottom view of the main part observed from below.

[0011] Figure 4 It is along Figure 2 A cross-sectional view of line AA in the diagram.

[0012] Figure 5 This is a front view of the front of the internal combustion engine after the shock absorber cover has been removed.

[0013] Figure 6 This is a front view of the front of an internal combustion engine, illustrating the flow of air.

[0014] Figure 7 This refers to the shock absorber of the second embodiment and... Figure 4 Same cross-sectional view. Detailed Implementation

[0015] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Figures 1-5 This describes the structure of the front end portion of an internal combustion engine having the shock absorber cooling structure described in this invention. This embodiment of the internal combustion engine is used, for example, as a power generation internal combustion engine to drive a generator in a series hybrid vehicle. Figure 1 As shown, a metal chain cover 2, made of die-cast aluminum alloy or similar material, is installed on the cylinder block 1 using multiple bolts 3, covering the valve device on the front end face of the cylinder block 1 with a chain chamber (not shown). The front end of the crankshaft 4 passes through the chain cover 2. Figure 5 As shown, a disc-shaped shock absorber 5 is mounted on the front end of the crankshaft 4. In this embodiment, the cylinder block 1 and the chain cover 2 are equivalent to the "internal combustion engine body" in the technical solution.

[0016] The rear end of the crankshaft 4 (not shown) is connected, for example, to a generator (not shown) configured in series with respect to the internal combustion engine. Furthermore, in this specification, based on common usage and regardless of the vehicle's mounting configuration, the side from which the internal combustion engine output is taken, i.e., the generator side, is referred to as the "rear" side of the internal combustion engine, and the opposite side, where the timing chain for the valve mechanism is located, is referred to as the "front" side. In the following description, unless otherwise specified, the terms "front" and "rear" refer to the front / rear of the internal combustion engine.

[0017] In one embodiment, the internal combustion engine is mounted in the vehicle in a so-called "lateral" configuration, meaning that the crankshaft 4 is orthogonal to the longitudinal direction of the vehicle. Specifically, in one embodiment, the internal combustion engine is mounted with its "front" side located on the right side of the vehicle. Furthermore, the cylinder center axis of the internal combustion engine is approximately along the vertical direction of the vehicle; that is, the internal combustion engine becomes... Figure 2 The posture shown. Therefore, in this specification, unless otherwise specified, the term "below" refers to... Figure 2 The lower side of the middle.

[0018] like Figure 5 As shown, the shock absorber 5 consists of the following components: an inner peripheral component 8, which is fixed to the front end of the crankshaft 4 by a central bolt 7; a cylindrical outer peripheral component 9, which has the required mass for shock absorption; and a cylindrical elastic component, such as a rubber component 10, which is located between the inner peripheral component 8 and the outer peripheral component 9. Figure 4 As shown, the inner peripheral component 8 has a central boss 8a and a cylindrical edge 8b, and a rubber component 10 is firmly bonded to the outer peripheral surface of the edge 8b and the inner peripheral surface of the outer peripheral component 9.

[0019] like Figure 5 As shown, when viewed from the front, the shock absorber 5 (in other words, the crankshaft 4) rotates clockwise. The shock absorber 5 suppresses the torsional vibration of the crankshaft 4.

[0020] Here, in a preferred embodiment, such as Figure 4 As shown, the rear end 9a of the outer peripheral surface of the outer peripheral component 9 is formed as a conical surface whose diameter increases as it moves further back.

[0021] A shock absorber cover 11, which covers the shock absorber 5, is installed on the front surface of the chain cover 2. This shock absorber cover 11 also serves as a soundproof cover to shield the timing chain and other sounds from inside the internal combustion engine, and is made of a synthetic resin material with excellent cushioning properties. In one embodiment, the chain cover 2 is installed in a so-called co-fastening manner by bolts 3 used to fix the chain cover 2 to the cylinder block 1.

[0022] The shock absorber cover 11 has: a cup-shaped portion, namely a cup body portion 12, having an inner diameter corresponding to the diameter of the shock absorber 5; and a flat portion 13, which overlaps with the outer surface of the chain cover 2 around the cup body portion 12. Furthermore, the cup body portion 12 has: a cylindrical peripheral wall portion 14, which covers the peripheral surface of the shock absorber 5; and a flat end wall portion 15, which covers the front end surface of the shock absorber 5. Here, the cup body portion 12 is formed as a frustum-shaped cone with a relatively small diameter on the end wall portion 15 side; therefore, the inner peripheral surface 14a of the peripheral wall portion 14, opposite to the peripheral surface of the shock absorber 5, is formed as an inclined conical surface with a relatively small diameter on the end wall portion 15 side.

[0023] Furthermore, the peripheral wall portion 14 of the cup body portion 12, which is formed as part of the shock absorber cover 11, is not strictly continuous at 360°, but is formed in a shape with the lower surface side (shown as 12a) open. That is, as Figure 2 As shown, when viewed from the front, the cup body 12 is shaped like a horseshoe, and the lower surface side 12a does not have a peripheral wall 14.

[0024] Compared to the structure of the lower surface 12a of the cup body portion 12, a fuel tank portion 31 protruding in a frame-like manner towards the front of the internal combustion engine is formed at the lower end of the chain cover 2. This fuel tank portion 31 forms an oil reservoir within the space (not shown) on its inner side (cylinder block 1 side), which becomes part of the chain chamber. It has: a bottom wall 31a protruding forward from the plate-like portion of the chain cover 2; two side walls 31b and 31c; and a flat top wall 31d. Furthermore, it has a front wall 31e connecting the front edges of the bottom wall 31a, side walls 31b and 31c, and top wall 31d to each other. In other words, the fuel tank portion 31 is formed as an elongated, box-shaped protrusion.

[0025] Here, the upper surface of the top wall 31d of the fuel tank section 31 is formed as a flat surface parallel to the axial direction of the crankshaft 4, and a shock absorber cover 11 is installed along the upper surface of the top wall 31d. Moreover, the opening surface of the lower surface side 12a of the cup body section 12 is covered by the upper surface of the top wall 31d.

[0026] Furthermore, the front wall 31e of the fuel tank section 31 is formed as a flat surface along a plane orthogonal to the axial direction relative to the crankshaft 4, and the outer surface of the front wall 31e is as follows: Figure 1 When combined with the shock absorber cover 11, the components are arranged in a manner that forms the same plane as the outer surface of the end wall 15 of the shock absorber cover 11.

[0027] Therefore, when the shock absorber cover 11 and the oil tank 31 are combined, the space in the cup body 12 becomes a space that does not open on the lower surface side 12a but surrounds the entire circumference of the shock absorber 5.

[0028] Thus, the shock absorber cover 11 surrounding the shock absorber 5 is provided with: an air inlet 21 for drawing in cooling air from the outside into the space inside the cup body 12 by means of a pump action accompanying the rotation of the shock absorber 5; and an air outlet 22 for discharging warm air from the space inside the cup body 12 to the outside.

[0029] Air inlet 21 is disposed downward at the center of the lower end of the end wall 15 of the cup body 12. Specifically, a forward-protruding bulge 15a is formed at the center of the lower end of the end wall 15 along the vertical direction. The lower end of this bulge 15a extends forward from the top wall 31d of the oil tank section 31, thereby... Figure 4The air inlet 21 is configured to open downwards as shown. Therefore, in terms of the axial position of the crankshaft 4, the air inlet 21 is located further forward than the front end face of the shock absorber 5. Furthermore, as... Figure 4 As shown, the preferred bulge 15a extends upward to the inner circumference of the edge 8b of the shock absorber 5.

[0030] like Figure 1 , Figure 2 As shown, a portion of the peripheral wall 14 of the cup body 12 is cut into a window shape to form an air outlet 22. As a circumferential position centered on the shock absorber 5, the air outlet 22 is located adjacent to the air inlet 21; specifically, it is arranged adjacent to the downstream side of the air inlet 21 in the rotational direction of the shock absorber 5. Furthermore, as an axial position of the crankshaft 4, an opening is formed at the rearmost position of the peripheral wall 14. Figure 4 As shown, the air outlet 22 is located further back than the front end face of the shock absorber 5, opposite to the rear end portion of the outer peripheral side component 9 of the shock absorber 5, and more specifically, opposite to the rear end 9a, which is a conical surface.

[0031] Therefore, as a positional relationship along the axial direction of crankshaft 4, air inlet 21 and air outlet 22 are offset from each other. Air inlet 21 is located relatively forward, and air outlet 22 is located relatively rearward, and the two do not overlap each other in the axial direction of crankshaft 4.

[0032] In this embodiment, the shock absorber 5 rotates at high speed inside the shock absorber housing 11 to obtain a pumping action, drawing air in from the air inlet 21 and discharging the heated air that cools the shock absorber 5 from the air outlet 22. Figure 6 This indicates the airflow within the shock absorber housing 11. Due to the centrifugal force accompanying the high-speed rotation of the shock absorber 5, a low-pressure area is generated near the center of the shock absorber 5, such as... Figure 6 As indicated by arrow F1, air flows into the cup body 12 from the air inlet 21. The air flowing in from the air inlet 21 is forced by the rotation of the damper 5 and circulates along the inner circumferential surface 14a of the peripheral wall 14 of the cup body 12 as indicated by arrow F2. Here, an air outlet 22 is located immediately downstream of the air inlet 21, but the two are offset from each other axially along the crankshaft 4, therefore, according to… Figure 4 It is easy to understand that the air flowing in from the air inlet 21 does not flow directly out to the air outlet 22. Therefore, the air flows in a spiral pattern around the outer periphery of the cup body 12, and after circling at least once, it exits from the air outlet 22 as indicated by arrow F3. That is, the air swirls at least 360° within the cup body 12.

[0033] Conversely, the offset relationship between the air inlet 21 and the air outlet 22 is set based on simulation and the like so that the air flowing in from the air inlet 21 will not immediately flow out from the air outlet 22 at the assumed internal combustion engine rotation speed.

[0034] The cooling air flows around the entire circumference of the shock absorber 5, thus effectively cooling the shock absorber 5. In addition, even when viewed axially from the crankshaft 4, the airflow flows across the shock absorber 5 in a front-to-back direction from the front to the rear of the shock absorber 5, thus effectively cooling the entire shock absorber 5.

[0035] Here, in the above embodiment, the inner peripheral surface 14a of the peripheral wall portion 14 of the cup body portion 12 is formed as a conical surface, so the airflow subjected to centrifugal force is guided rearward due to the inclination of the conical surface. Therefore, the discharge of air from the air outlet 22 at the rear end of the space within the cup body portion 12 is facilitated, resulting in smoother airflow within the cup body portion 12. That is, the peripheral wall portion 14 is formed in a conical shape, guiding the swirling flow axially from the front air inlet 21 towards the rear air outlet 22, thereby promoting flow.

[0036] Furthermore, in the above embodiment, the rear end 9a of the outer peripheral component 9 of the shock absorber 5 is formed as a conical surface opposite to the air outlet 22, which guides the swirling flow coming from the axial direction to the outer peripheral side, thus promoting the discharge of air through the air outlet 22. As a result, the airflow flowing within the cup body 12 becomes smoother.

[0037] In particular, by combining the conical surface of the peripheral wall portion 14 of the cup body portion 12 with the conical surface of the rear end portion 9a on the side of the shock absorber 5, a spiral airflow inside the cup body portion 12 can be formed more reliably.

[0038] Furthermore, when an internal combustion engine is installed in a vehicle, Figure 2 The right side faces the front of the vehicle. Figure 2 The left side faces the rear of the vehicle. Therefore, the air outlet 22 of the cup body 12 opens towards the rear of the vehicle. Thus, the airflow from the air outlet 22 is not obstructed by the wind blowing from the vehicle.

[0039] Furthermore, the air inlet 21 is shaped to be surrounded by the bulge 15a and facing downwards, and the front wall 31e of the fuel tank section 31 is located further downwards than the air inlet 21. Therefore, water droplets and other foreign objects splashing from above and below the vehicle toward the shock absorber cover 11 are less likely to enter the air inlet 21.

[0040] The present invention has been described in detail above with respect to one embodiment, but the present invention is not limited to the above embodiment and various modifications can be made. For example, in the above embodiment, only the rear end 9a of the outer peripheral surface of the shock absorber 5 is partially formed as a conical surface, but the entire outer peripheral surface can also be made as a conical surface.

[0041] In addition, such as Figure 7 As shown in the second embodiment, the outer peripheral surface of the shock absorber 5 can also be formed as a simple cylindrical surface instead of a conical surface.

[0042] Similarly, the peripheral wall 14 of the cup body 12 can be formed as a simple cylindrical shape instead of a conical surface. Even with this cylindrical shape, a spiral airflow can be formed towards the air outlet 22 after circling the air inlet 21 once.

[0043] Alternatively, it can be configured such that the chain guard 2 does not have an oil tank section 31, and the cup section 12 surrounds the entire circumference of the shock absorber 5, including the lower part.

[0044] In addition, the present invention can also be applied to a shock absorber that also serves as a crankshaft pulley for belt winding.

Claims

1. A shock absorber cooling structure for an internal combustion engine, wherein a disc-shaped shock absorber is mounted on a rotating shaft protruding from the end face of the engine body, and a cover is provided to cover the shock absorber, wherein... The aforementioned enclosure is equipped with an air inlet for guiding air into the space inside the enclosure through the action of a pump that accompanies the rotation of the aforementioned shock absorber, and an air outlet for discharging air from the aforementioned space. The aforementioned air inlet and air outlet are offset from each other in the axial direction of the crankshaft. The aforementioned air outlet is arranged adjacent to the circumferential downstream side of the aforementioned air inlet in such a way that the air flowing in from the aforementioned air inlet, which is located in an offset position, is discharged after swirling 360°.

2. A shock absorber cooling structure for an internal combustion engine, wherein a disc-shaped shock absorber is mounted on a rotating shaft protruding from the end face of the engine body, and a cover is provided to cover the shock absorber, wherein... The aforementioned enclosure is equipped with an air inlet for guiding air into the space inside the enclosure through the action of a pump that accompanies the rotation of the aforementioned shock absorber, and an air outlet for discharging air from the aforementioned space. The aforementioned air inlet and air outlet are offset from each other in the axial direction of the crankshaft. The aforementioned cover has a cup-shaped portion that covers the end face and peripheral surface of the aforementioned shock absorber. The inner circumferential surface of the cup-shaped portion is formed as a conical surface that is inclined in the direction of guiding the swirling flow from the air inlet to the air outlet along the crankshaft axis.

3. A shock absorber cooling structure for an internal combustion engine, wherein a disc-shaped shock absorber is mounted on a rotating shaft protruding from the end face of the engine body, and a cover is provided to cover the shock absorber, wherein... The aforementioned enclosure is equipped with an air inlet for guiding air into the space inside the enclosure through the action of a pump that accompanies the rotation of the aforementioned shock absorber, and an air outlet for discharging air from the aforementioned space. The aforementioned air inlet and air outlet are offset from each other in the axial direction of the crankshaft. At least a portion of the outer peripheral surface of the aforementioned shock absorber is provided with a conical surface that is inclined in the direction of guiding the swirling flow from the air inlet to the air outlet along the crankshaft axis.

4. The shock absorber cooling structure for an internal combustion engine according to any one of claims 1 to 3, wherein, Viewed axially from the crankshaft, the air inlet is located relatively separated from the main body of the internal combustion engine, and the air outlet is located relatively close to the main body of the internal combustion engine.

5. The shock absorber cooling structure for an internal combustion engine according to any one of claims 1 to 4, wherein, The lower surface of the aforementioned shock absorber is covered by the aforementioned cover or other internal combustion engine components. The air inlet is positioned downwards on the portion of the cover that covers the end face of the shock absorber.

6. The shock absorber cooling structure for an internal combustion engine according to any one of claims 1 to 5, wherein, The aforementioned internal combustion engine is mounted on the vehicle with the crankshaft axis orthogonal to the vehicle's longitudinal direction. The aforementioned air outlets open towards the rear of the vehicle.

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