Internal combustion engine

Abstract

To set a nominal diameter of a bolt for fastening a mounting bracket in accordance with a position.SOLUTION: First and fourth bracket fixation bolts 31a, 31d fix one end part in an internal combustion engine body width direction of an internal combustion engine side mounting bracket 6. Third and sixth bracket fixation bolts 31c, 31f fix the other end part of the internal combustion engine side mounting bracket 6. A fifth bracket fixation bolt 31e fixes a central portion in the internal combustion engine body width direction in a lower edge part of the internal combustion engine side mounting bracket 6. A second bracket fixation bolt 31b fixes a central portion in the internal combustion engine body width direction in an upper edge part of the internal combustion engine side mounting bracket 6. A nominal diameter of the second bracket fixation bolt 31b is set smaller than that of each of the first to fourth and sixth bracket fixation bolts 31a, 31b, 31c, 31d, 31f.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an internal combustion engine mounted on a vehicle.

Background Art

[0002] For example, Patent Document 1 discloses a chain case in which a support bracket portion is integrally formed to fix a chain cover portion and an engine mount, which is a component for suspending the engine from the vehicle body.

[0003] In the chain case of Patent Document 1, the positions of the bolts for fixing the support bracket portion to the cylinder head and the cylinder block are determined so that the support bracket portion can be securely and easily fixed to the cylinder head and the cylinder block with a small number of bolts.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the chain case in Patent Document 1, although the positions of the bolts for fixing the support bracket portion to the cylinder head and the cylinder block have been considered, the thickness of the bolts for fixing the support bracket portion to the cylinder head and the cylinder block has not been considered.

[0006] That is, when fixing the support bracket portion with bolts, there is room for further improvement in terms of selecting the thickness (nominal diameter) of the bolts according to the positions of the bolts to be fixed.

Means for Solving the Problems

[0007] The internal combustion engine has a first bolt that fixes one end of a mount bracket for attaching the internal combustion engine body to the vehicle to the end face on one end side of the internal combustion engine body, a second bolt that fixes the other end of the mount bracket to the end face on one end side in the cylinder row direction of the internal combustion engine body, and a third bolt that fixes the central portion in the width direction of the mount bracket with respect to the internal combustion engine body to the end face on one end side in the cylinder row direction of the internal combustion engine body. The nominal diameter of the third bolt is formed to be smaller than the nominal diameters of the first bolt and the second bolt.

Advantages of the Invention

[0008] Since the nominal diameter of the third bolt is smaller, the dimensions of the boss portion through which the third bolt passes can be reduced, and overall, an increase in the size of the internal combustion engine body can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each figure, the X-axis is the axis along the front-rear direction of the internal combustion engine 1 (the axis parallel to the central axis of the crankshaft 19 of the internal combustion engine 1), the Y-axis is the axis along the left-right direction (the width direction of the internal combustion engine) of the internal combustion engine 1, and the Z-axis is the axis along the up-down direction of the internal combustion engine 1 (the axis parallel to the cylinder axis L1 of the internal combustion engine 1). That is, the X-axis is the axis along the cylinder bank direction of the internal combustion engine 1 or the internal combustion engine body 8 (described later). Also, the Y-axis is the axis along the width direction of the internal combustion engine body 8.

[0011] FIG. 1 is an explanatory diagram schematically showing the schematic configuration of the internal combustion engine 1 to which the present invention is applied.

[0012] The internal combustion engine 1 is, for example, an in-line multi-cylinder internal combustion engine, and includes a cylinder head 2, a cylinder block 3 attached to the lower part of the cylinder head 2, a cam bracket 4 attached to the upper part of the cylinder head 2, a front cover 5 covering the front surface of the internal combustion engine body 8, and an engine-side mount bracket 6 as a metal mount bracket located on the front surface of the front cover 5.

[0013] Note that the reference numeral 7 in FIG. 1 is a vehicle-body-side mount bracket fixed to the vehicle body side. The cylinder head 2, the cylinder block 3, and the cam bracket 4 constitute the internal combustion engine body 8. Therefore, the front cover 5 covers the end surface 8a on one end side in the cylinder bank direction of the internal combustion engine body 8.

[0014] The cylinder head 2 is a casting made of a metal material such as an aluminum alloy, and an intake port (not shown) for supplying intake air to the combustion chamber (not shown) and an exhaust port (not shown) for discharging exhaust from the combustion chamber (not shown) are formed.

[0015] The cylinder block 3 is a casting made of a metal material such as an aluminum alloy, and a number of cylinders 43 (see FIGS. 5 and 6) corresponding to the number of cylinders are formed.

[0016] The cam bracket 4 is made of a metal material such as an aluminum alloy, and rotatably supports a camshaft (not shown) together with the cylinder head 2.

[0017] The front cover 5 is made of a synthetic resin material such as polyamide, and is liquid-tightly attached to the internal combustion engine body 8 so as to cover the front surface of the internal combustion engine body 8. More specifically, the front cover 5 is attached to the front surface of the cylinder block 3, the front surface of the cylinder head 2, the front surface of the cam bracket 4, etc. by fixing bolts 10, 11, etc. (see FIGS. 4 to 6). In other words, the front cover 5 is attached to the internal combustion engine body 8 so as to cover the end surfaces of one end side of the cylinder block 3 and the cylinder head 2 in the crankshaft axis direction, that is, the end surface 8a of one end side in the cylinder row direction of the internal combustion engine body 8.

[0018] The front cover 5 has a shallow dish shape and forms a space between it and the front surface of the internal combustion engine body 8, which is the end surface 8a of one end side in the cylinder row direction of the internal combustion engine body 8. In this space, a cranksprocket (not shown) fixed to the crankshaft 19 (see FIG. 4) and a camssprocket (not shown) fixed to the front end of a camshaft (not shown) are accommodated. A timing chain 41 (see FIGS. 5 and 6) for transmitting rotational power is wound around these cranksprocket and camssprocket. That is, the space formed between the front cover 5 and the internal combustion engine body 8 is an environment having the timing chain 41 that performs oil lubrication. The timing chain 41 is a chain that transmits the rotational force of the crankshaft 19. The space formed between the front cover 5 and the internal combustion engine body 8 is liquid-tight with respect to the outside because the space between the front cover 5 and the internal combustion engine body 8 is liquid-tightly sealed via sealing materials 25, 26, etc. (see FIG. 3).

[0019] As shown in FIGS. 2 and 3, the front cover 5 is formed with a boss portion through-hole 13, a crankshaft through-hole 14, a first bolt through-hole 15, a second bolt through-hole 16, and a gauge insertion port 50. FIG. 2 is a front view of the front cover 5. FIG. 3 is a rear view of the front cover 5.

[0020] The boss portion through-hole 13 is for the bolt boss portion 32 (see FIGS. 4 and 5) of the internal combustion engine side mount bracket 6 to pass through, and is formed at two locations in the central portion of the front cover 5 in the width direction of the internal combustion engine body 8. The outer peripheral edge of the boss portion through-hole 13 is an annular (cylindrical) through-hole peripheral portion 17. The through-hole peripheral portion 17 is pressed against and contacts the end face 8a on one end side in the cylinder row direction of the internal combustion engine body 8 on the back side of the front cover 5, and supports the central portion of the front cover 5 on the internal combustion engine body 8. The space between the through-hole peripheral portion 17 and the internal combustion engine body 8 is sealed liquid-tightly by a through-hole sealing material 26. That is, the periphery of the through-hole peripheral portion 17 is sealed by the through-hole sealing material 26 over the entire circumference.

[0021] As shown in FIG. 4, the second bolt boss portion 32b passes through the boss portion through-hole 13a. A through-hole peripheral portion 17a is formed around the boss portion through-hole 13a. The through-hole peripheral portion 17a is pressed against the cylinder head 2 on the back side of the front cover 5. Above the through-hole peripheral portion 17a in the vertical direction (direction along the Z axis) of the front cover 5, a front cover boss portion 21a is adjacent.

[0022] The boss portion through-hole 13b is located below the boss portion through-hole 13a in the vertical direction (direction along the Z axis) of the front cover 5, and as shown in FIG. 4, the fifth bolt boss portion 32e passes through it. A through-hole peripheral portion 17b is formed around the boss portion through-hole 13b. The through-hole peripheral portion 17b is pressed against the cylinder block 3 on the back side of the front cover 5. Below the through-hole peripheral portion 17b in the vertical direction (direction along the Z axis) of the front cover 5, a front cover boss portion 21b is adjacent.

[0023] The crankshaft through-hole 14 is for the crankshaft 19 to pass through, and its periphery is sealed in a liquid-tight manner.

[0024] The first bolt through-hole 15 is for the first fixing bolt 10 that fixes the front cover 5 to the internal combustion engine body 8 to pass through, and a plurality (a large number) of them are formed on the outer peripheral edge of the front cover 5. The outer peripheral edge of the front cover 5 is sealed in a liquid-tight manner over the entire circumference by an annular outer peripheral edge sealing material 25. The outer peripheral edge sealing material 25 is located on the inner peripheral side of the first bolt through-hole 15.

[0025] The second bolt through-hole 16 is for the second fixing bolt 11 (see FIGS. 4 and 6) that fixes the portion other than the outer peripheral edge of the front cover 5 to the internal combustion engine body 8 to pass through, and a plurality (for example, two places) of them are formed on the front cover 5. The second bolt through-hole 16 is formed in the front cover boss portion 21.

[0026] The front cover boss portion 21 is formed at a position that does not overlap with the internal combustion engine side mount bracket 6 when viewed in the crankshaft axial direction. That is, the second fixing bolt 11 corresponding to the boss portion fixing bolt is arranged at a position that does not overlap with the internal combustion engine side mount bracket 6 when viewed in the crankshaft axial direction, and the internal combustion engine side mount bracket 6 is fixed to the end face 8a of the internal combustion engine body 8 at this position.

[0027] The front cover boss portion 21 is fixed on the back side of the front cover 5 with its front end face pressed against the end face 8a on one end side in the cylinder row direction of the internal combustion engine body 8.

[0028] Specifically, the front cover boss portion 21a is fixed on the back side of the front cover 5 with its front end face pressed against the cylinder head 2. The front cover boss portion 21b is fixed on the back side of the front cover 5 with its front end face pressed against the cylinder block 3. A second bolt through-hole 16a is formed in the front cover boss portion 21a. A second bolt through-hole 16b is formed in the front cover boss portion 21b.

[0029] Note that between the front cover boss portion 21 and the internal combustion engine main body 8, it is liquid-tightly sealed by a through-hole sealing material 26 that seals the periphery of the through-hole 17. That is, the front cover boss portion 21a and the adjacent through-hole peripheral portion 17a are liquid-tightly sealed from the internal combustion engine main body 8 by the through-hole sealing material 26a. The front cover boss portion 21b and the adjacent through-hole peripheral portion 17b are liquid-tightly sealed from the internal combustion engine main body 8 by the through-hole sealing material 26b.

[0030] Also, the mating surface (first mating surface) between the through-hole peripheral portion 17 and the end face 8a of the internal combustion engine main body 8, and the mating surface (second mating surface) between the front cover boss portion 21 and the end face 8a of the internal combustion engine main body 8 are formed to be located on the same plane.

[0031] That is, the mating surface between the through-hole peripheral portion 17a and the end face 8a of the internal combustion engine main body 8, and the mating surface between the front cover boss portion 21a and the end face 8a of the internal combustion engine main body 8 are formed to be located on the same plane. Also, the mating surface between the through-hole peripheral portion 17b and the end face 8a of the internal combustion engine main body 8, and the mating surface between the front cover boss portion 21b and the end face 8a of the internal combustion engine main body 8 are formed to be located on the same plane. Further, these four mating surfaces may be formed to be located on the same plane.

[0032] The gauge insertion port 50 is a hole formed through the upper part of the front cover 5 into which an oil level gauge (not shown) is inserted.

[0033] Figure 4 is a front view of the internal combustion engine 1 to which the internal combustion engine side mount bracket 6 is attached.

[0034] The internal combustion engine side mount bracket 6 is attached to the end face 8a on one end side in the cylinder row direction of the internal combustion engine main body 8 without contacting the front cover 5. The internal combustion engine side mount bracket 6 is a casting made of a metal material such as an aluminum alloy, and is a member for attaching the internal combustion engine main body 8 (internal combustion engine 1) to the vehicle.

[0035] The internal combustion engine side mount bracket 6 is attached to the end faces on one end side of the cylinder head 2 and the cylinder block 3 by six bracket fixing bolts 31, namely the first bracket fixing bolt 31a to the sixth bracket fixing bolt 31f. The bracket fixing bolts 31 penetrate through the bolt boss portions 32 of the internal combustion engine side mount bracket 6.

[0036] The internal combustion engine side mount bracket 6 is formed such that the length along the width direction of the internal combustion engine body 8 is longer than that of the front cover 5. The internal combustion engine side mount bracket 6 overlaps with a part of the outer surface of the front cover 5 with a predetermined gap in the cylinder row direction of the internal combustion engine body 8 and is attached to the internal combustion engine body 8. That is, the internal combustion engine side mount bracket 6 is attached to the internal combustion engine body 8 so as not to contact the front cover 5.

[0037] As shown in FIG. 4, the internal combustion engine side mount bracket 6 straddles the outside of the front cover 5 in the width direction of the front cover 5 (the direction along the Y axis) and is fixed to the internal combustion engine body 8 on both sides of the front cover 5. That is, the internal combustion engine side mount bracket 6 is attached to the internal combustion engine body 8 outside the outer peripheral edge of the front cover 5.

[0038] For the internal combustion engine side mount bracket 6, the upper edge portion in the vertical direction along the cylinder axis L1 of the internal combustion engine 1 is fixed to the internal combustion engine body 8 by the first bracket fixing bolt 31a to the third bracket fixing bolt 31c. For the internal combustion engine side mount bracket 6, the lower edge portion in the vertical direction along the cylinder axis L1 of the internal combustion engine 1 is fixed to the internal combustion engine body 8 by the fourth bracket fixing bolt 31d to the sixth bracket fixing bolt 31f.

[0039] Specifically, at the upper edge portion of the engine side mount bracket 6, both end portions in the width direction of the engine body 8 are fixed to the engine body 8 by the first bracket fixing bolt 31a and the third bracket fixing bolt 31c outside the front cover 5. Also, at the upper edge portion of the engine side mount bracket 6, the central portion in the width direction of the engine body 8 is fixed to the engine body 8 by the second bracket fixing bolt 31b that penetrates the front cover 5.

[0040] At the lower edge portion of the engine side mount bracket 6, both end portions in the width direction of the engine body 8 are fixed to the engine body 8 by the fourth bracket fixing bolt 31d and the sixth bracket fixing bolt 31f outside the front cover 5. Also, at the lower edge portion of the engine side mount bracket 6, the central portion in the width direction of the engine body 8 is fixed to the engine body 8 by the fifth bracket fixing bolt 31e that penetrates the front cover 5.

[0041] The first bracket fixing bolt 31a penetrates the first bolt boss portion 32a of the engine side mount bracket 6. The first bolt boss portion 32a is formed on one end side of the engine side mount bracket 6 in the width direction of the engine body 8.

[0042] The second bracket fixing bolt 31b penetrates the second bolt boss portion 32b of the engine side mount bracket 6. The second bolt boss portion 32b is formed at the central portion of the engine side mount bracket 6 in the width direction of the engine body 8.

[0043] The second bolt boss portion 32b penetrates the boss portion through hole 13a so that the outer peripheral surface does not contact the inner peripheral surface of the boss portion through hole 13a of the front cover 5. The tip portion on the back side of the front cover 5 of the second bolt boss portion 32b is pressed against the cylinder head 2.

[0044] The third bracket fixing bolt 31c passes through the third bolt boss portion 32c of the engine-side mount bracket 6. The third bolt boss portion 32c is formed at the other end side of the engine-side mount bracket 6 in the width direction of the engine body 8.

[0045] The fourth bracket fixing bolt 31d passes through the fourth bolt boss portion 32d of the engine-side mount bracket 6. The fourth bolt boss portion 32d is formed at one end side of the engine-side mount bracket 6 in the width direction of the engine body 8.

[0046] The fifth bracket fixing bolt 31e passes through the fifth bolt boss portion 32e of the engine-side mount bracket 6. The fifth bolt boss portion 32e is formed at the central portion of the engine-side mount bracket 6 in the width direction of the engine body 8.

[0047] The fifth bolt boss portion 32e passes through the boss portion through-hole 13b so that the outer peripheral surface does not contact the inner peripheral surface of the boss portion through-hole 13b of the front cover 5. The tip portion on the back side of the front cover 5 of the fifth bolt boss portion 32e is pressed against the cylinder block 3.

[0048] The sixth bracket fixing bolt 31f passes through the sixth bolt boss portion 32f of the engine-side mount bracket 6. The sixth bolt boss portion 32f is formed at the other end side of the engine-side mount bracket 6 in the width direction of the engine body 8.

[0049] The first bracket fixing bolt 31a and the fourth bracket fixing bolt 31d correspond to the first bolt, and fix one end of the engine-side mount bracket 6 in the width direction of the engine body to the end face 8a of the engine body 8. The nominal diameter of the first bracket fixing bolt 31a and the fourth bracket fixing bolt 31d is, for example, M10.

[0050] The second bracket fixing bolt 31b corresponds to the fourth bolt, and fixes the central portion in the width direction of the engine body of the upper edge portion of the engine side mounting bracket 6 to the end face 8a of the engine body 8. The nominal diameter of the second bracket fixing bolt 31b is, for example, M10.

[0051] The third bracket fixing bolt 31c and the sixth bracket fixing bolt 31f correspond to the second bolt, and fix the other end portion in the width direction of the engine body of the engine side mounting bracket 6 to the end face 8a of the engine body 8. The nominal diameters of the third bracket fixing bolt 31c and the sixth bracket fixing bolt 31f are, for example, M10.

[0052] The fifth bracket fixing bolt 31e corresponds to the third bolt, and fixes the central portion in the width direction of the engine body of the lower edge portion of the engine side mounting bracket 6 to the end face 8a of the engine body 8. The nominal diameter of the fifth bracket fixing bolt 31e is, for example, M6. That is, as shown in FIGS. 5 and 6, the fifth bracket fixing bolt 31e has a smaller nominal diameter and a shorter length than the other bracket fixing bolts 31.

[0053] FIG. 5 is an explanatory diagram showing a cross section taken along line A-A of FIG. 4. FIG. 6 is an explanatory diagram showing a cross section taken along line B-B of FIG. 4.

[0054] As shown in FIGS. 5 and 6, the timing chain 41 is pressed toward the central portion of the engine body 8 in the width direction of the engine body by the arms 42 from both sides sandwiching the fifth bracket fixing bolt 31e. The left and right arms 42 are in slidable contact with the timing chain 41. In addition, reference numeral 43 in FIGS. 5 and 6 is a cylinder of the internal combustion engine 1 formed in the cylinder block 3.

[0055] When the internal combustion engine side mount bracket 6 supports the internal combustion engine body 8 on the vehicle, when the center part is deformed due to torsion around the axis along the width direction of the internal combustion engine body, it may have an adverse effect on the support of the internal combustion engine body 8 and thus the internal combustion engine 1. In particular, when the internal combustion engine side mount bracket 6 has a length that extends over the entire width of the internal combustion engine body 8, the center part is more likely to be deformed.

[0056] However, in the internal combustion engine 1 of the above-described embodiment, since the central portion of the internal combustion engine side mount bracket 6 is fixed to the internal combustion engine body 8 by the second bracket fixing bolt 31b and the fifth bracket fixing bolt 31e, deformation near the center of the internal combustion engine side mount bracket 6 is suppressed.

[0057] In particular, since the nominal diameter of the fifth bracket fixing bolt 31e for fixing the internal combustion engine side mount bracket 6 to the cylinder block 3 is reduced, overall enlargement of the internal combustion engine body 8 can be suppressed. That is, in the internal combustion engine 1, as the nominal diameter of the fifth bracket fixing bolt 31e becomes smaller, the dimensions of the boss portion through which the fifth bracket fixing bolt 31e passes can be reduced, and overall enlargement of the internal combustion engine body 8 can be suppressed. The boss portion through which the fifth bracket fixing bolt 31e passes corresponds to, for example, the second bolt boss portion 32b of the internal combustion engine side mount bracket 6, the peripheral portion 17b of the through hole of the front cover 5, and the portion where the fifth bracket fixing bolt 31e of the cylinder block 3 is coupled.

[0058] Since the nominal diameter of the fifth bracket fixing bolt 31e is small, overall the length of the threaded portion can be shortened, and as shown in FIG. 6, it can be made less likely to interfere with the water jacket 44 formed inside the internal combustion engine body 8 in the cylinder bank direction of the internal combustion engine body 8. That is, in the internal combustion engine 1, as the nominal diameter of the fifth bracket fixing bolt 31e becomes smaller, the length of the fifth bracket fixing bolt 31e becomes shorter and it becomes less likely to interfere with the water jacket 44, so enlargement of the internal combustion engine body 8 can be suppressed. The water jacket 44 is a cooling water passage formed around the cylinder 43.

[0059] Since the nominal diameter of the fifth bracket fixing bolt 31e of the internal combustion engine 1 is small, the occupancy range along the width direction of the internal combustion engine body required for fixing the fifth bracket fixing bolt 31e is reduced, and the timing chain 41 can be sufficiently pressed in the width direction of the internal combustion engine body by the arm 42. Therefore, the internal combustion engine 1 can reliably suppress the free span of the timing chain 41.

[0060] Even if the internal combustion engine 1 presses the timing chain 41 toward the center of the internal combustion engine body 8 in the width direction of the internal combustion engine body, since the nominal diameter of the fifth bracket fixing bolt 31e is small, a mating surface sufficient for arranging the through-hole sealing material 26b around the boss portion through-hole 13b and the second bolt through-hole 16b can be secured.

[0061] If the boss portion around the screw hole into which the fifth bracket fixing bolt 31e is inserted of the internal combustion engine 1 interferes with the water jacket 44, there is a risk that the water jacket 44 will be narrowed and the cooling performance will deteriorate.

[0062] However, since the nominal diameter of the fifth bracket fixing bolt 31e of the internal combustion engine 1 is small, the depth (length) of the screw hole into which the fifth bracket fixing bolt 31e is inserted can be made shallow (short), the interference between the fifth bracket fixing bolt 31e and the water jacket 44 can be suppressed, and the deterioration of the cooling performance can be suppressed (avoided).

[0063] The internal combustion engine 1 can improve the sealing property around the boss portion through-hole 13 and the second bolt through-hole 16 by bringing the central portion of the front cover 5 in the width direction of the internal combustion engine body into close contact with the internal combustion engine body 8, and can suppress the film vibration of the front cover 5.

[0064] Since the front cover boss portion 21, which is a portion where the internal combustion engine 1 cannot block the radiated noise by the internal combustion engine side mount bracket 6, is fixed to the internal combustion engine body 8 by the second fixing bolt 11, the film vibration of the front cover 5 is suppressed and the radiated noise can be reduced.

[0065] Of the six bracket fixing bolts 31 that fix the engine side mount bracket 6 to the engine body 8, the one with the smaller nominal diameter in the internal combustion engine 1 is only one fifth bracket fixing bolt 31e. Specifically, for the internal combustion engine 1, the second bracket fixing bolt 31b that fixes the center of the upper edge portion of the engine side mount bracket 6 is a large-diameter bolt having the same nominal diameter as the first bracket fixing bolt 31a, the third bracket fixing bolt 31c, the fourth bracket fixing bolt 31d, and the sixth bracket fixing bolt 31f. The fifth bracket fixing bolt 31e that fixes the center of the lower edge portion of the engine side mount bracket 6 is a small-diameter bolt having a nominal diameter smaller than that of the first bracket fixing bolt 31a, the third bracket fixing bolt 31c, the fourth bracket fixing bolt 31d, and the sixth bracket fixing bolt 31f. Therefore, the internal combustion engine 1 can achieve both the vehicle support performance and the compactness of the internal combustion engine 1.

[0066] For the internal combustion engine 1, the nominal diameter of the bolt 31 that fixes the engine side mount bracket 6 to the engine body 8 is such that the first bracket fixing bolt 31a, the second bracket fixing bolt 31b, the third bracket fixing bolt 31c, the fourth bracket fixing bolt 31d, and the sixth bracket fixing bolt 31f are M10, and the fifth bracket fixing bolt 31e is M6.

[0067] In the case of an internal combustion engine 1 for an automobile, in order to ensure the support performance while suppressing the increase in size, it is the most appropriate choice to set the nominal diameter of the bracket fixing bolt 31 to such a size.

[0068] As described above, specific embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit thereof.

[0069] For example, a front cover boss portion 21 may be additionally formed between a through-hole peripheral portion 17a and a through-hole peripheral portion 17b in the vertical direction (direction along the Z-axis) of the front cover 5, or at a position below the through-hole peripheral portion 17b in the vertical direction (direction along the Z-axis) of the front cover 5, and a second bolt through-hole 16 of these front cover boss portions 21 may be formed. In this case, the front cover 5 is also fixed to the internal combustion engine main body 8 (cylinder block 3) by bolts passing through these additionally formed second bolt through-holes 16.

[0070] For example, the internal combustion engine 1 may be one in which the internal combustion engine side mount bracket 6 is fixed to the end face 8a of the internal combustion engine main body 8 by five bracket fixing bolts 31, namely, first, third to sixth bracket fixing bolts 31a, 31c, 31d, 31e, 31f. That is, at least one bolt having a smaller nominal diameter than the other bracket fixing bolts 31 may be used to fix the central portion of the internal combustion engine side mount bracket 6 in the width direction of the internal combustion engine main body.

Explanation of Signs

[0071] 1…Internal combustion engine 2…Cylinder head 3…Cylinder block 5…Front cover 6…Internal combustion engine side mount bracket 8…Internal combustion engine main body 8a…End face 10…First fixing bolt 11…Second fixing bolt 13…Boss portion through-hole 15…First bolt through-hole 16…Second bolt through-hole 17…Through-hole peripheral portion 21…Front cover boss portion 25…Outer peripheral edge sealing material 26…Through-hole sealing material 31…Bracket fixing bolt 31a…First bracket fixing bolt (first bolt) 31b…Second bracket fixing bolt (fourth bolt) 31c… Third bracket fixing bolt (second bolt) 31d… Fourth bracket fixing bolt (first bolt) 31e… Fifth bracket fixing bolt (third bolt) 31f… Sixth bracket fixing bolt (second bolt) 32… Bolt boss part 41… Timing chain 42… Arm

Claims

1. a mount bracket located at one end side of the internal combustion engine body in a cylinder row direction and used to attach the internal combustion engine body to a vehicle; a first bolt for fixing one end of the mount bracket in a width direction of the internal combustion engine body to an end face on one end side of the internal combustion engine body in a cylinder row direction; a second bolt for fixing the other end of the mount bracket in the width direction of the internal combustion engine body to an end face on one end side of the internal combustion engine body in the cylinder row direction; a third bolt for fixing a central portion of the mount bracket in a width direction of the internal combustion engine body to an end face on one end side of the internal combustion engine body in a cylinder row direction, An internal combustion engine, wherein the third bolt has a nominal diameter smaller than the nominal diameters of the first bolt and the second bolt.

2. 2. The internal combustion engine according to claim 1, characterized in that a chain for transmitting a rotational force of a crankshaft and an arm with which the chain is in slidable contact are disposed on one end side of the internal combustion engine body in a cylinder row direction.

3. a front cover that covers an end face of one end of the internal combustion engine body in a cylinder row direction and has an outer circumferential edge that is attached to the internal combustion engine body; the chain and the arm are accommodated in a liquid-tight manner between an end face of one end of the internal combustion engine body in a cylinder row direction and the front cover, The mounting bracket is disposed so as to straddle the outer side of the front cover, the first bolt and the second bolt fix the mount bracket to the internal combustion engine body on an outer side of the front cover in a width direction of the internal combustion engine body, the third bolt passes through a through hole formed in a central portion of the front cover in a width direction of the internal combustion engine body to fix the mount bracket to the internal combustion engine body, 3. The internal combustion engine according to claim 2, wherein the periphery of the through hole is sealed with a sealing material.

4. A cooling water passage through which cooling water flows is formed around the cylinder formed in the cylinder block of the internal combustion engine body, 4. The internal combustion engine according to claim 3, wherein the third bolt secures the mounting bracket to the cylinder block.

5. the front cover is made of a resin material and has a front cover boss portion formed around the through hole and pressed against an end face on one end side of the internal combustion engine body in a cylinder row direction, a first mating surface which is a mating surface between a periphery of the through hole and an end surface on one end side of the internal combustion engine body in a cylinder row direction; 4. The internal combustion engine according to claim 3, wherein a second mating surface, which is a mating surface between the front cover boss portion and an end face on one end side of the internal combustion engine body in the cylinder row direction, is formed to be positioned on the same plane.

6. The front cover boss portion is fixed to an end face on one end side in a cylinder row direction of the internal combustion engine body by a boss portion fixing bolt passing therethrough, 6. The internal combustion engine according to claim 5, wherein the boss portion fixing bolt is disposed at a position not overlapping with the mount bracket when viewed in the axial direction of the crankshaft.

7. The mount bracket has an upper edge and a lower edge in a vertical direction along a cylinder axis, each of which is fixed to an end surface on one end side in a cylinder row direction of the internal combustion engine body by three bolts, the three bolts that fix the upper edge portion to the internal combustion engine body are the first bolt, the second bolt, and a fourth bolt that fixes a central portion of the upper edge portion in the internal combustion engine body width direction to the internal combustion engine body, the three bolts that fix the lower edge portion to the internal combustion engine body are the first bolt, the second bolt, and the third bolt; 7. The internal combustion engine according to claim 6, wherein the fourth bolt has the same nominal diameter as the first bolt and the third bolt.

8. 8. The internal combustion engine according to claim 7, wherein the first bolt, the second bolt and the fourth bolt have a nominal diameter of M10, and the third bolt has a nominal diameter of M6.

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