JP2007154913A - Power transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce deviation in fixing position of a rotary power transmission means. <P>SOLUTION: This power transmission system transmitting power between a plurality of rotational shafts, comprises: an intermediate shaft 7 provided with a level difference 7e which is formed to an outer peripheral surface thereof, and whose one end part 7a side is larger in diameter than the other end part 7b side; a gear 8 in which a part of the other end part 7b side of the intermediate shaft 7; a sprocket 9 in which a part of the other end part 7b side of the intermediate shaft 7 is inserted and which is disposed to be in parallel with the first gear 8; a camshaft of an engine provided with a sprocket 9, in which a chain is wound around the sprocket and the sprocket 9, and which is one of the plurality of rotational shafts; a crankshaft which is provided with a gear meshed with the gear 8 and is one of the plurality of rotational shafts; and a nut 26 pushing the gear 8 and the sprocket 9 against the level difference 7e so as to fix them to the intermediate shaft 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission device for transmitting power between a plurality of rotating shafts, and in particular, a power transmitting device in which a rotating power transmitting means around which a wound power transmitting body is wound and a gear are fixed to one rotating shaft. Relates to the device.

As a power transmission device that transmits power between two rotating shafts, a device that employs a chain is known. (Patent Document 1) This power transmission device transmits power between a crankshaft and a camshaft of an engine, and sprockets are respectively fixed to these rotary shafts.
Japanese Patent Laid-Open No. 8-312367 (FIG. 1)

  Here, in order to transmit power from the crankshaft to the input shaft of the fuel pump together with the camshaft, a sprocket and a gear are fixed to this one input shaft, and the space between the crankshaft and the input shaft of the fuel pump is fixed. Some gears transmit power through a chain between the input shaft and the camshaft. In this device, the input shaft of the fuel pump is formed in a taper shape. The input shaft is inserted into a hole formed in the gear, and the gear is pressed against the tapered surface, so that the gear and the input shaft slip. The power is reliably transmitted from the crankshaft to the fuel pump. Further, by fixing the sprocket and the gear, the power from the crankshaft is reliably transmitted to the camshaft via the gear and the sprocket.

  However, in this power transmission device, since the gear is positioned on the input shaft by the taper, the gear may be displaced from an appropriate position and fixed to the input shaft due to manufacturing errors. Furthermore, since the sprocket is fixed to the gear, if the gear is displaced from an appropriate position with respect to the input shaft, the sprocket is also displaced from an appropriate position with respect to the input shaft. If the sprocket is displaced from an appropriate position in this manner, the chain and the sprocket may rattle, and noise may be generated or drive efficiency may be reduced.

  SUMMARY OF THE INVENTION Accordingly, the present invention provides a power transmission device that fixes a rotational power transmission means and a gear around which a wrapping power transmission body is wound with a shift of a fixed position of the rotational power transmission means to a single rotation shaft. The purpose is to provide.

  For this reason, the invention according to claim 1 is a power transmission device that transmits power between a plurality of rotating shafts, and is provided on the outer peripheral surface with a step whose one end side is larger in diameter than the other end side. The first rotating shaft, the first gear into which the other end portion of the first rotating shaft is inserted, and the first gear into which the other end portion of the first rotating shaft is inserted. As the plurality of rotating shafts, the first rotating power transmission means arranged side by side and the second rotating power transmission means around which the winding power transmission body is wound together with the first rotating power transmission means are provided. The second rotating shaft and the second gear that meshes with the first gear are provided, the third rotating shaft as a plurality of rotating shafts, the first gear and the first rotational power transmission means are stepped. And a fixing means that is pressed against the first rotating shaft and fixed to the first rotating shaft.

The invention described in claim 2 is characterized in that the fixing means is a nut that is screwed into a screw portion formed on the outer peripheral surface of the first rotating shaft.
According to a third aspect of the present invention, there is provided a locking means for locking the first gear and the first rotational power transmission means in the rotational direction.
The invention according to claim 4 is characterized in that the locking means is a knock pin provided between the first gear and the first rotational power transmission means.

The invention according to claim 5 is characterized in that the first rotating shaft is an input shaft of an engine auxiliary machine, and the second rotating shaft is an engine camshaft.
The invention according to claim 6 is characterized in that the third rotating shaft is an engine crankshaft.
The invention according to claim 7 is characterized in that the auxiliary machine is a fuel pump for supplying fuel to the engine.

  According to the first aspect of the present invention, the first rotating power transmission means and the first gear are pressed against the step by the fixing means and fixed to the first rotating shaft. By this step, the first rotational power transmission means and the first gear are positioned in the axial direction. Thereby, the shift | offset | difference of the fixed position of the 1st rotational power transmission means with respect to a 1st rotating shaft can be suppressed.

According to the second aspect of the present invention, as the fixing means for fixing the first gear and the first rotational power transmission means to the first rotating shaft, a large diameter having an outer diameter of the first rotating shaft as a screw diameter. Nuts can be used. Thereby, since the tightening torque of the nut can be secured, the first rotational power transmission means and the first gear can be fixed to the first rotating shaft without slipping.
According to the third aspect of the present invention, the first rotational power transmission means and the first gear are locked in the rotation direction by the locking means. Therefore, power can be reliably transmitted between the second rotating shaft and the third rotating shaft.

According to the fourth aspect of the present invention, the locking means can be realized with a simple structure.
According to the fifth aspect of the present invention, the displacement of the fixed position of the first rotational power transmission means with respect to the input shaft of the accessory is reduced, and power is transmitted between the cam shaft of the engine and the input shaft of the accessory. Shaking between the winding power transmission body and the first rotational power transmission means can be reduced.
According to the invention of claim 6, power can be reliably transmitted from the crankshaft of the engine to the camshaft by the locking means.

  According to the seventh aspect of the present invention, it is possible to reduce the shift of the fixed position of the first rotational power transmission means with respect to the input shaft of the fuel pump.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a layout explanatory diagram of a power transmission device according to an embodiment of the present invention employed in an engine. FIG. 2 is a structural diagram of the power transmission device according to the present embodiment.
As shown in FIG. 1, one end of the crankshaft 3 projects through the front surface of the cylinder block 2 in front of the cylinder block 2 of the engine 1. A gear 4 that is a helical gear is attached to one end of the crankshaft 3.

A front plate 5 is fixed to the front surface of the cylinder block 2. A fuel pump 6 is fixed to the front plate 5. The input shafts of the crankshaft 3 and the fuel pump 6 are arranged in parallel to each other.
An intermediate shaft 7 is rotatably supported on the front plate 5 coaxially with the input shaft of the fuel pump 6. The ends of the intermediate shaft 7 and the input shaft of the fuel pump 6 are connected to each other. A gear 8 that is a helical gear and a sprocket 9 are fixed to the intermediate shaft 7. (See FIG. 2) The sprocket 9 corresponds to the first rotational power transmission means of the present invention. In the present invention, the rotational power transmission means is a device in which a wrapping power transmission body is wound and power is transmitted / received through the winding power transmission body. In a narrow sense, a pulley corresponds to a pulley other than a sprocket.

The gear 4 and the gear 8 mesh with each other via an idler gear 10 that is a helical gear, and power is transmitted from the crankshaft 3 to the intermediate shaft 7, that is, from the crankshaft 3 to the input shaft of the fuel pump 6. . The idler gear 10 is rotatably supported by an idler shaft 11 fixed to the cylinder block 2.
A sprocket 13 is attached to one end of the camshaft 12 of the engine 1. A chain 14 is wound between the sprocket 9 and the sprocket 13, and power is transmitted from the intermediate shaft 7 to the camshaft 12.

  As shown in FIG. 2, a cylindrical mount bracket 21 is interposed between the fuel pump 6 and the front plate 5. A flange portion 21 a is formed at an intermediate portion in the axial direction of the mount bracket 21. The flange portion 21 a protrudes outward in the radial direction of the mount bracket 21 and is fastened to the front plate 5 by a bolt 22. One end 21 b of the mount bracket 21 passes through a hole 5 a formed in the front plate 5. One end 7 a of the intermediate shaft 7 is inserted into a hole formed on the one end 21 b side of the mount bracket 21. The intermediate shaft 7 is rotatably supported by the mount bracket 21 and the front plate 5 by a bearing 23. An input shaft 6 a of the fuel pump 6 is inserted into a hole formed on the other end 21 c side of the mount bracket 21. The fuel pump 6 is fastened to the other end 21 c of the mount bracket 21 by a bolt 24. The input shaft 6 a of the fuel pump 6 and the one end portion 7 a of the intermediate shaft 7 are connected by an Oldham coupling 25.

FIG. 3 is an enlarged view showing the structure of the attachment portion of the sprocket 9 and the gear 8.
The other end portion 7b of the intermediate shaft 7 protrudes outward from the mount bracket 21, and the protruding portion includes a screw portion 7c and a gear insertion portion 7d in order from the other end portion 7b to the one end portion 7a. And the level | step difference 7e is formed. The screw portion 7c is formed by screwing the other end portion 7b of the intermediate shaft 7. The gear insertion portion 7d is a portion that is inserted into a hole formed in the gear 8 and the sprocket 9, and the diameter thereof is constant throughout this portion. The step 7e is formed so that the one end portion 7a side has a large diameter from the gear insertion portion 7d. Then, the other end portion 7b of the intermediate shaft 7 is inserted in the order of the gear 8 and the sprocket 9 and the nut 26 is tightened, so that the gear 8 and the sprocket 9 are sandwiched between the step 7e and the nut 26 and attached to the intermediate shaft 7. Fixed. The gear 8 and the sprocket 9 are locked to each other by a knock pin 27, and the sprocket 9 rotates as the gear 8 rotates.

The intermediate shaft 7 corresponds to the first rotating shaft of the present invention. Further, the camshaft 12 of the engine 1 is the second rotating shaft, the crankshaft 3 is the third rotating shaft, the gear 8 is the first gear, the sprocket 13 is the second rotating power transmission means, and the gear 4 Corresponds to the second gear, the nut 26 corresponds to the fixing means, and the knock pin 27 corresponds to the locking means.
With the above-described configuration, the gear 4 rotates with the rotation of the crankshaft 3, whereby the gear 8 rotates through the idler gear 10. As the gear 8 rotates, the intermediate shaft 7 rotates and power is transmitted to the input shaft 6 a of the fuel pump 6. Further, the sprocket 9 rotates as the gear 8 rotates. As a result, power is transmitted to the camshaft 12 through the chain 14 wound around the sprocket 9. Further, by tightening the nut 26, the side surface 8a of the gear 8 is pressed against the step 7e and the gear 8 and the sprocket 9 are positioned in the axial direction with respect to the intermediate shaft 7, so that the displacement of the sprocket 9 with respect to the intermediate shaft 7 is reduced. The Thereby, rattling between the sprocket 9 and the chain 14 is reduced, and generation of noise and reduction in driving efficiency can be suppressed.

  Moreover, since the nut 26 for fixing the gear 8 and the sprocket 9 to the intermediate shaft 7 can be used with a large diameter that matches the diameter of the threaded portion 7c of the intermediate shaft 7, a sufficient tightening torque can be secured. Can do. Thereby, the gear 8 and the sprocket 9 can be firmly fixed to the intermediate shaft 7, and the sprocket 9 and the like can be prevented from falling off and slipping. Furthermore, since the gear 8 and the sprocket 9 are locked by the knock pin 27, power can be reliably transmitted from the crankshaft 3 to the camshaft 12. In addition, since the gear 8 and the sprocket 9 are fixed together with one nut 26 in order to fix the gear 8 and the sprocket 9 to the intermediate shaft 7, the number of parts can be reduced.

  In this embodiment, power is transmitted between the crankshaft 3 and the intermediate shaft 7 by a gear and between the intermediate shaft 7 and the camshaft 12 by a chain. The present invention can also be applied to the case where power is transmitted between the intermediate shaft 7 and the camshaft 12 using a gear. In addition, the present invention can be applied to a structure in which a plurality of gears 8 and a sprocket 9 are fixed to the intermediate shaft 7, and the axial displacement of the sprocket 9 can be reduced.

In the present embodiment, power is transmitted between the intermediate shaft 7 and the camshaft 12 via the chain 14, but it is also possible to apply power transmitted by a belt. In this case, the pulley around which the belt is wound corresponds to the first rotational force transmitting means, and the axial displacement of the pulley can be reduced.
Further, in the present invention, the input shaft 6a of the fuel pump 6 is connected to the intermediate shaft 7. However, the present invention is not limited to this. For example, other auxiliary machines such as a vacuum pump, a generator or a water pump are used. It is also possible to apply one that is connected to the input shaft, or one in which the intermediate shaft 7 simply supports the sprocket 9 and the gear 8 without connecting the input shaft of these auxiliary machines.

Layout explanatory diagram of a power transmission device according to an embodiment of the present invention employed in an engine Structure diagram of power transmission device according to this embodiment Enlarged view showing detailed structure of sprocket and gear mounting

Explanation of symbols

3 Crankshaft 4 Gear 6 Fuel pump 6a Input shaft 7 Intermediate shaft
8 Gear 9 Sprocket 14 Chain 12 Camshaft 13 Sprocket 26 Nut 27 Knock Pin

Claims (7)

A power transmission device for transmitting power between a plurality of rotating shafts,
A first rotating shaft provided with a step on the outer peripheral surface with one end portion having a larger diameter than the other end portion;
A first gear into which a portion on the other end side of the first rotating shaft is inserted;
A first rotational power transmission means that is inserted in a portion on the other end side of the first rotary shaft and is arranged alongside the first gear;
A second rotating shaft as the plurality of rotating shafts, provided with a second rotating power transmitting means on which a winding power transmitting body is wound together with the first rotating power transmitting means;
A third rotation shaft as the plurality of rotation shafts, provided with a second gear meshing with the first gear;
Fixing means for pressing the first gear and the first rotational power transmission means against the step and fixing the first gear and the first rotational power transmission means to the first rotation shaft;
A power transmission device configured to include.   The power transmission device according to claim 1, wherein the fixing means is a nut that is screwed into a screw portion formed on an outer peripheral surface of the first rotating shaft.   The power transmission device according to claim 1, further comprising a locking unit that locks the first gear and the first rotational power transmission unit in a rotation direction.   4. The power transmission device according to claim 3, wherein the locking means is a knock pin provided between the first gear and the first rotational power transmission means. The first rotating shaft is an input shaft of an auxiliary machine of the engine,
The power transmission device according to claim 1, wherein the second rotation shaft is a camshaft of the engine.   The power transmission device according to claim 5, wherein the third rotation shaft is a crankshaft of the engine.   The power transmission device according to claim 5, wherein the auxiliary machine is a fuel pump that supplies fuel to the engine.

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