Abstract: An object is to provide a bolt fastening structure which is resistant to loosening even in an environment with vibration. A fastening structure 100 according to the invention of the present application is configured such that a male screw 10 having a thread section 11 with a thread ridge 11a and a thread groove 11b, and a female screw 20 forming a recess 20 in a first member 300 serving as a fastening target, the female screw 20 having a threaded section 21 formed in the recess 20 and engaged with the thread section 11, are in a fastened state. In the fastened state, a tip portion 12 forming a leading end of the male screw 10 is in point contact with a bottom surface 23a of the recess 20.

Abstract: A connection member for connecting an exhaust manifold and an exhaust pipe of an internal combustion engine, includes a flange portion, a boss portion and an attachment portion. The flange portion has a plate shape with an opening configured to be fixed to the exhaust pipe in a state where the opening communicates with the exhaust pipe. The boss portion is provided to bulge from the flange portion on an outside of the opening in a radial direction of the opening, is configured so that a sensor configured to detect components of the exhaust is attached to the boss portion, and is configured to be fixed to a portion of an outer circumferential surface of the exhaust pipe. The attachment portion protrudes from the flange portion and is configured so that a protection member which covers the exhaust pipe is attached to the attachment portion.

Abstract: An exhaust system structure of an internal combustion engine, includes an exhaust manifold which is configured to be connected to a cylinder of the internal combustion engine, an exhaust pipe which is provided on a downstream side of an exhaust flow from the exhaust manifold, a connection member including a flange portion which connects the exhaust pipe and the exhaust manifold to each other and a boss portion which is provided integrally with the flange portion and is fixed to a portion of an outer circumferential surface of the exhaust pipe, a sensor which is attached to the boss portion and is configured to detect components of the exhaust, and a purification device which is connected to a downstream end of the exhaust pipe and is disposed on a side opposite to the boss portion with respect to the exhaust pipe.

Abstract: A horizontal groove extending horizontally when an alternator bracket is fixed to a cylinder block of a vehicle engine is formed in the alternator bracket. A shank of a bolt inserted through mounting pieces of an alternator is inserted into the horizontal groove from a horizontally lateral direction toward the cylinder block to support the bolt on a lower surface of the horizontal groove. After insertion, the bolt is restrained from moving toward an opening of the horizontal groove. Since the insertion of the bolt into the horizontal groove is facilitated, and the weight of the alternator is borne by the lower surface of the horizontal groove, a burden on a fixing portion is reduced, and it becomes easy to position the alternator and hold it when it is fixed. Thus, the accessory can be mounted on the cylinder block with satisfactory work efficiency and with support accuracy kept high.

Abstract: A horizontal groove extending horizontally when an alternator bracket is fixed to a cylinder block of a vehicle engine is formed in the alternator bracket. A shank of a bolt inserted through mounting pieces of an alternator is inserted into the horizontal groove from a horizontally lateral direction toward the cylinder block to support the bolt on a lower surface of the horizontal groove. After insertion, the bolt is restrained from moving toward an opening of the horizontal groove. Since the insertion of the bolt into the horizontal groove is facilitated, and the weight of the alternator is borne by the lower surface of the horizontal groove, a burden on a fixing portion is reduced, and it becomes easy to position the alternator and hold it when it is fixed. Thus, the accessory can be mounted on the cylinder block with satisfactory work efficiency and with support accuracy kept high.