JP2020056326A - Balancer device of internal combustion engine - Google Patents

Abstract

To provide a balancer device of an internal combustion engine that can freely switch a connected state between a crankshaft and a balancer shaft.SOLUTION: A balancer device 10 comprises a balancer shaft 20, and a driven gear 30 to be rotated integrally with the balancer shaft 20, and connected to a drive gear 101 of the crankshaft 100. The driven gear 30 comprises a gear body part 31 comprising a tooth part 31a, a hub part 32 located radially inside the gear body part 31, and to be rotated integrally with balancer shaft 20, and a connection switching part 40 for switching the gear body part 31 and the hub part 32 to one of a connected state and a disconnected state. The connection switching part 40 comprises a piston part 41 to be moved along a radial direction by controlling a solenoid valve 26 of a supply passage 25 serving as an oil passage and changing an oil pressure, and switches the gear body part 31 and the hub part 32 to one of the connected state and the disconnected state by a position of the piston part 41.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a balancer device for an internal combustion engine.

There is known an internal combustion engine including a balancer device having a balancer shaft that rotates in synchronization with a crankshaft (for example, see Patent Document 1).
In the balancer device of Patent Document 1, a plurality of gears are provided between the balancer shaft and the crankshaft, and the rotational driving force of the crankshaft can be transmitted to the balancer shaft. Further, in the balancer device of Patent Literature 1, a temperature sensitive member is provided between a driven gear (balance shaft gear in Patent Literature 1) attached to the balancer shaft and the balancer shaft, and the balancer is deformed according to a temperature change. The connection state between the shaft and the driven gear is changed. Specifically, as the temperature of the internal combustion engine and the temperature of the lubricating oil rise, the temperature of the temperature-sensitive member also rises, and the temperature-sensitive member deforms to connect the balancer shaft and the driven gear via the temperature-sensitive member. State. Thereby, the rotational driving force of the crankshaft is transmitted to the balancer shaft, and the balancer shaft rotates in synchronization with the crankshaft.

JP 2002-349283 A

  However, in the above-described balancer device, there is a problem that the connection state between the crankshaft and the balancer shaft cannot be freely switched because the temperature-sensitive member that changes in response to a temperature change is used to switch the connection state.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a balancer device that can freely switch a connection state between a crankshaft and a balancer shaft.

  A balancer device that solves the above problem includes a balancer shaft, a driven gear that rotates integrally with the balancer shaft and is connected to a drive gear of a crankshaft, wherein the driven gear includes a gear body having teeth, a gear A hub portion that is positioned radially inside the main body portion and rotates integrally with the balancer shaft, and a connection switching portion that switches the gear main body portion and the hub portion to one of a connected state and a non-connected state, The connection switching unit has a piston portion that is moved in a radial direction by controlling a valve portion of an oil passage to change oil pressure, and the gear body portion and the The hub is switched to one of a connected state and a non-connected state.

  According to this configuration, the gear body and the hub can be switched between the connected state and the non-connected state depending on the position of the piston that moves due to a change in hydraulic pressure. The state and the unconnected state will be switched. Thereby, the connection state between the crankshaft and the balancer shaft can be freely switched by changing the hydraulic pressure.

Explanatory drawing which shows schematic structure of the balancer apparatus and crankshaft in one Embodiment. Sectional drawing which shows the non-connection state of the driven gear of the balancer apparatus in the embodiment. Sectional drawing which shows the non-connection state of the driven gear of the balancer apparatus in the embodiment. Sectional drawing which shows the connection state of the driven gear of the balancer apparatus in the embodiment. Sectional drawing which shows the connection state of the driven gear of the balancer apparatus in the embodiment.

  Hereinafter, an embodiment of a balancer device for an internal combustion engine will be described with reference to the drawings. In the drawings, some components may be exaggerated or simplified for convenience of description. Also, the dimensional ratio of each part may be different from the actual one. The balancer device 10 according to the present embodiment is a device provided in an in-line three-cylinder internal combustion engine.

  As shown in FIG. 1, the crankshaft 100 of the internal combustion engine includes a plurality of journals 100a rotatably supported on a crankcase (not shown). The central axis N of each journal 100a coincides with the central axis of the crankshaft 100, and the direction in which the central axis N extends is the axial direction of the crankshaft 100.

  A pair of crank arms 100b is provided between adjacent journals 100a, and a crank pin 100c to which a connecting rod of an internal combustion engine is attached is provided between the pair of crank arms 100b. Since the internal combustion engine of the present embodiment is an in-line three-cylinder engine, the crankshaft 100 is provided with three crankpins 100c.

  When the three cylinders are a first cylinder, a second cylinder, and a third cylinder, respectively, a connecting rod of the first cylinder is attached to a crank pin 100c provided at a position closest to the drive gear 101. Further, a connecting rod of the third cylinder is attached to a crank pin 100c provided at a position farthest from the drive gear 101. The connecting rod of the second cylinder is assembled to the remaining crank pins 100c.

  At the axial end of the crankshaft 100, a substantially disc-shaped protruding shaft 100d is provided so as to protrude coaxially with the central axis N. The central axis of the protruding shaft 100d coincides with the central axis N of the journal 100a.

  A disk-shaped drive gear 101 having a tooth portion 101a on the outer periphery is fixed to the protruding shaft 100d. The central axis of the drive gear 101 coincides with the central axis N, and the central axis N is the center of rotation of the drive gear 101.

  Below the crankshaft 100, a balancer shaft 20 that suppresses vibration of the crankshaft 100 caused by movement of a piston of the internal combustion engine is arranged. The balancer shaft 20 forms a part of the balancer device 10.

  As shown in FIG. 1, the balancer shaft 20 includes a rod-shaped shaft main body 21. The shaft body 21 is rotatably supported by a bearing 23 provided in a balancer housing 22. The central axis J of the shaft main body 21 is along the axial direction of the crankshaft 100, and the direction in which the central axis J extends is the axial direction of the shaft main body 21. That is, the shaft main body 21 and the crankshaft 100 are arranged substantially in parallel.

  Balancer masses 21a and 21b for suppressing vibration are fixed to both axial sides of the shaft body 21, respectively. Each balance mass 21a, 21b is provided at a position opposite by 180 degrees in the circumferential direction (rotation direction).

  A disk-shaped driven gear 30 having a tooth portion 31a on its outer periphery that is in mesh with the drive gear 101 is fixed to a position adjacent to the balancer mass 21a at one axial end of the shaft body 21. The center axis of the driven gear 30 coincides with the center axis J, and the center axis J is the center of rotation of the driven gear 30. The drive gear 101 and the driven gear 30 have the same number of teeth, and the drive gear 101 and the driven gear 30 rotate at a constant speed.

  An oil passage 24 through which lubricating oil passes is formed in the shaft main body 21 of the balancer shaft 20. The oil passage 24 has a first oil passage 24a along the central axis J of the shaft main body 21, and a second oil passage 24b radially branched from the first oil passage 24a. The second oil passage 24b extends to a bearing 23 that supports the shaft main body 21 so that lubricating oil can be supplied to the bearing 23. The oil passage 24 communicates with a supply passage 25 of an external oil pump, and the presence or absence of lubricating oil supply into the oil passage 24 is determined by the open / close state of a solenoid valve 26 provided in the middle of the supply passage 25. Specifically, when the electromagnetic valve 26 is closed, lubricating oil is not supplied into the oil passage 24, and when the electromagnetic valve 26 is open, lubricating oil is supplied into the oil passage 24. . The open / close state of the solenoid valve 26 of this embodiment is controlled by a control unit (not shown).

  As shown in FIG. 1, the driven gear 30 is provided with a substantially annular gear body 31 having teeth 31 a meshing with the drive gear 101, and is provided radially inside the gear body 31 and fixed to the shaft body 21. And a hub portion 32.

The hub portion 32 is fixed to the shaft main body 21 and can rotate integrally with the shaft main body 21.
As shown in FIGS. 2 and 4, the hub portion 32 is provided with two fitting grooves 32 a on its outer peripheral surface. The fitting grooves 32a are provided one by one at both ends in the axial direction of the hub portion 32. C-rings 33 are fitted into the fitting grooves 32a, respectively, and the gear body 31 is positioned by the C-rings 33.

  As shown in FIGS. 2 to 5, a connection switching unit 40 that connects the hub 32 and the gear body 31 so as to be integrally rotatable is provided between the hub 32 and the gear body 31. The connection switching unit 40 has a piston part 41 and a spring part 42.

The piston portion 41 is urged by a spring portion 42 inward in the radial direction on the hub portion 32 side.
Here, a housing portion 32b recessed radially inward is provided on the outer peripheral side of the hub portion 32, and the spring portion 42 and the piston portion 41 can be housed in the housing portion 32b. The housing portion 32b is provided between the two fitting grooves 32a at a substantially central position in the axial direction of the hub portion 32.

  The housing portion 32b is connected to an in-gear oil passage 32c formed in the hub portion 32. The in-gear oil passage 32c communicates with the first oil passage 24a in the shaft main body 21. Therefore, whether or not lubricating oil is supplied to the in-gear oil passage 32c is also determined for the in-gear oil passage 32c by opening and closing the solenoid valve 26 as described above. Here, when the lubricating oil is supplied to the in-gear oil passage 32c, the piston portion 41 in the housing portion 32b moves radially outward against the urging force of the spring portion 42 by hydraulic pressure.

  The gear main body 31 includes a tooth portion 31a on its outer peripheral portion that meshes with the tooth portion 101a of the drive gear 101. The gear body 31 has a concave portion 31b which is depressed radially outward on an inner peripheral portion thereof, and a part of the piston portion 41 can be fitted therein. The concave portion 31b engages with the piston portion 41 in the circumferential direction (that is, the rotation direction of the driven gear 30) when a part of the piston portion 41 is fitted. The piston portion 41 is arranged so as to be fitted into both the concave portion 31b and the housing portion 32b so that the piston portion 41 straddles both the gear body portion 31 and the hub portion 32. Thereby, the piston part 41 can be engaged with the gear body part 31 and the hub part 32 in the rotation direction. Thus, the gear body 31 and the hub 32 are switched from the unconnected state to the connected state.

Next, the operation and effect of the balancer device 10 configured as described above will be described.
In the balancer device 10 of the present embodiment, when the hydraulic pressure acting on the piston portion 41 by controlling the electromagnetic valve 26 is less than the urging force of the spring portion 42, the piston portion 41 is moved toward the hub portion 32 by the urging force of the spring portion 42. Being energized. At this time, the entire piston portion 41 is housed in the housing portion 32b of the hub portion 32, and the hub portion 32 and the gear main body 31 are not connected. Therefore, even when the crankshaft 100 is driven to rotate, the gear body 31 of the driven gear 30 idles, and the driving force is not transmitted to the balancer shaft 20 (the shaft body 21).

  When the hydraulic pressure acting on the piston 41 by controlling the electromagnetic valve 26 is equal to or greater than the urging force of the spring 42, the piston 41 moves in the radial direction against the urging force of the spring 42. At this time, the hub portion 32 and the gear body portion 31 are connected via the piston portion 41 by fitting the piston portion 41 into both the concave portion 31b and the housing portion 32b. Therefore, when the crankshaft 100 is rotationally driven, the rotational driving force is transmitted to the balancer shaft 20 via the drive gear 101 and the driven gear 30, and the balancer shaft 20 is rotationally driven.

  As described above, by changing the oil pressure by controlling the electromagnetic valve 26, the gear body 31 and the hub 32 can be switched between the connected state and the unconnected state depending on the position of the piston 41. Thereby, the connection state between the crankshaft 100 and the balancer shaft 20 can be freely switched by changing the hydraulic pressure.

This embodiment can be implemented with the following modifications. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above embodiment, one drive gear 101 and one driven gear 30 are provided between the crankshaft 100 and the balancer shaft 20, but an idle gear is provided between the drive gear 101 and the driven gear 30. A configuration may be adopted.

-Although the balancer apparatus 10 of the said embodiment was applied to the in-line three-cylinder internal combustion engine, it can be similarly applied to an internal combustion engine having another cylinder arrangement or another number of cylinders.
-In the said embodiment, although it was set as the structure which has one solenoid valve 26, the number may be changed suitably.

  The arrangement positions of the balance masses 21a and 21b on the balancer shaft 20 and the shape of the balance masses 21a and 21b can be appropriately changed. The balance masses 21a and 21b may be configured separately from other members, or may be configured integrally. For example, in the above embodiment, the balance mass 21a may be integrated with the driven gear 30, and the balance mass 21b may be integrated with the shaft body 21 of the balancer shaft 20.

  DESCRIPTION OF SYMBOLS 10 ... Balancer apparatus, 20 ... Balancer shaft, 21 ... Shaft main body, 25 ... Supply path (oil path), 26 ... Solenoid valve (valve part), 30 ... Driven gear, 31 ... Gear main body part, 31a ... Tooth part, 32 ... Hub part, 40: connection switching part, 41: piston part, 100: crankshaft, 101: drive gear.

Claims (1)

A balancer shaft, and a driven gear that rotates integrally with the balancer shaft and is connected to a drive gear of the crankshaft;
The driven gear includes a gear body having teeth, a hub positioned radially inward of the gear body and integrally rotating with the balancer shaft, and a state where the gear body and the hub are connected to each other. A connection switching unit that switches to one of a connection state and a connection state,
The connection switching portion has a piston portion that is moved in a radial direction by changing a hydraulic pressure by controlling a valve portion of an oil passage, and the gear body portion and the hub portion are moved depending on a position of the piston portion. A balancer device for an internal combustion engine that switches between a connected state and a disconnected state.