JPH0218249Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine oil pump device used to pump lubricating oil to various parts of the engine.

[Conventional technology]

Conventionally, gear oil pumps have contributed to engine operation by sucking up lubricating oil stored in an oil pan and supplying the lubricating oil to various parts of an engine, such as a camshaft and a crankshaft.

By the way, when the engine is provided with a balancer shaft for balancing high-order inertial forces such as secondary, in order to share the drive system that transmits the rotation of the engine crankshaft to the gear oil pump and the balancer shaft, There is known a gear oil pump in which at least one of the driving gear and the driven gear is coupled to a balancer shaft.

An example of a gear oil pump having such a configuration is an engine balancer drive device disclosed in Japanese Patent Publication No. 57-34444. According to this device, the driven gear (driven gear) of the pump (oil pump) is fixed to a balancer shaft for balancing secondary inertia force.

[The problem that the idea aims to solve]

When the gear of the gear oil pump is coupled to the balancer shaft in this way, the following problems arise.

In order to maintain high-order balance such as secondary balance with the balancer shaft, it is necessary to rotate the balancer shaft at a speed twice as high as that of the crankshaft. On the other hand, in the case of a gear oil pump, as shown in FIG. 4, when the speed increases, the pressure between the teeth of each gear suddenly increases at the end. In other words, at low speeds, there is a leakage of pressure from the discharge side to the suction side through the gaps between the teeth and sides of the gear, so the pressure between the teeth gradually increases as it approaches the discharge side, but at high speeds, the pressure between the teeth gradually increases. Because there is no time for leakage, the pressure suddenly increases in the area shown in the diagram. Therefore, each time this portion is opened to the discharge port by rotation of the gear, an impact force is applied to the shaft of the gear. Generally, the gear and shaft rotate together relative to the bearing, so the impact force causes the gear to rotate abnormally, causing abnormal wear on the shaft and bearing.

The present invention has been made in view of the above conventional problems, and aims to provide an engine oil pump device that can reduce abnormal wear of the shaft and bearing of the driven gear of a gear oil pump. .

[Means to solve the problem]

The present invention is an oil pump device for an engine in which a drive gear of a gear oil pump is coupled to a balancer shaft driven by a crankshaft at a speed increasing ratio of twice or more, and the driven gear of the gear oil pump meshes with the drive gear. is rotatably supported on a driven gear shaft, and the driven gear shaft is rotatably supported on the engine side.

[Effect]

With the above configuration, the gear has a floating structure, so that even if the impact is applied to the driven gear shaft, this impact load is reduced (damped).

〔Example〕

FIG. 1 is a longitudinal sectional view of a gear oil pump in an engine oil pump device according to an embodiment of the present invention. In the figure, 1 is a casing, and bearings 4 and 5 that rotatably receive a balancer shaft 3 are fixed to this casing 1.
A drive gear 2 of a gear pump is attached to the balancer shaft 3. This driving gear 2 and a driven gear 6 that meshes with the driving gear 2 and is rotationally driven are housed in the casing 1. The center of the driven gear 6 is rotatably supported by a driven gear shaft 7, and the driven gear shaft 7 is rotatably supported by an engine case 8.

Further, a suction port 9 is provided on the lower side of the casing 1 for sucking lubricating oil stored in an oil pan (not shown), and a discharge port 10 is provided on the side near the center for sending lubricating oil to various parts of the engine. It is provided.

The drive gear 2 of the gear oil pump constructed in this manner is driven by the rotation of the sprocket 11 which is interlocked with the balancer shaft 3. This sprocket 11 is rotated via a transmission chain 15 by a crank pulley 13, which will be described later. Note that the casing 1 is fixed to the engine case 8. Further, oil is supplied from an oil passage 8a formed in the engine case 8 to one end 7a of the driven gear shaft 7, and this oil is supplied to the oil passage 7 formed in the driven gear shaft 7.
b, and is supplied to the other end of the driven gear shaft 7, etc., to lubricate each part.

FIGS. 2 and 3 are a longitudinal cross-sectional view and a plan view for explaining the main parts of the rotation transmission mechanism of the engine for driving the drive gear 2 of the gear oil pump.

In the figure, 12 is a crankshaft of the engine, and a crank pulley 13 is fixed to this crankshaft 12. This crank pulley 13, sprocket 11, and sprocket 1
A transmission chain 15 is engaged with the peripheral surface of 4,
Sprocket 11 and sprocket 14 are driven by rotation of crank pulley 13 at a rotation speed twice that of the crank pulley. One side of the sprocket 14 is a transmission gear 16
This transmission gear 16 is fixed to the balancer gear 1
It is interlocked with 7. This balancer gear 17
is supported by a balancer shaft 18 for balancing the secondary inertia force of engine rotation.

Next, the operation of this oil pump device will be explained. When the engine is driven, the crank pulley 1
3 is rotated, the sprocket 11 is rotated by the transmission of the transmission chain 15. This results in
The driving gear 2 and driven gear 6 of the oil pump are driven. Therefore, lubricating oil in the oil pan is sucked in through the suction port 9 and discharged to the discharge port 10 via a suction passage (not shown). This discharged lubricating oil is supplied to each part of the engine, returns to the oil pan, and is circulated through a similar circulation path.

Also, when the oil pump device is operating,
Since the drive gear 2 is coupled to the balancer shaft 3, the rotation speed of the gear oil pump becomes high, and the impact force acts on the driven gear 6 and the driven gear shaft 7 at high speeds, but the driven gear 6 is not driven. Since the driven gear shaft 7 is supported in a floating state with respect to the gear shaft 7 and the engine case 8 side, abnormal wear of the driven gear shaft 7 and the bearing (support part for the driven gear shaft 7) is reduced. Ru. In other words,
In general, the amount of wear on shafts and bearings is proportional to the value of [bearing load x relative sliding speed]. In particular, when a gear pump is at high speed, an impact load is added to the bearing load. 2 between drive gear shaft 7 and bearing
When the parts are rotated by sliding, the relative sliding speed at each part is reduced, a damping effect is obtained, and wear can be reduced. Furthermore, the impact force is absorbed by the oil film at each of the two sliding rotation parts, and this also provides the effect of suppressing abnormal wear.

[Effect of idea]

As described above, according to the present invention, the driven gear of the gear oil pump that meshes with the drive gear connected to the balancer shaft, which is driven by the crankshaft at a speed increasing ratio of twice or more, is rotated relative to the driven gear shaft. Since the driven gear shaft is rotatably supported relative to the engine side, impact force is applied to the driven gear when the gear oil pump rotates at high speed together with the balancer shaft. Also, the above impact force is reduced (damping) by relative slipping occurring at two locations, one between the driven gear and the driven gear shaft, and the other between the driven gear shaft and the bearing. Abnormal wear of the gear oil pump can be reduced, and the service life of the gear oil pump can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a gear oil pump in an engine oil pump device according to an embodiment of the present invention, FIG. 2 shows a main part of an engine rotation transmission mechanism that drives the gear oil pump, and FIG. 3 is a plan view of the rotation transmission mechanism, and FIG. 4 is a plan view of a gear of a gear oil pump and a pressure characteristic diagram showing the pressure between the teeth of this gear. 2... Drive gear, 3... Balancer shaft, 6... Driven gear, 7... Driven gear shaft, 8... Engine case (engine side), 12... Crankshaft.

Claims (1)

[Scope of utility model registration request] An oil pump device for an engine in which a drive gear of a gear oil pump is coupled to a balancer shaft driven by a crankshaft at a speed increase ratio of twice or more, wherein the driven gear of the gear oil pump that meshes with the drive gear is connected to the driven gear shaft. 1. An oil pump device for an engine, characterized in that the driven gear shaft is rotatably supported on the engine side, and the driven gear shaft is rotatably supported on the engine side.