JP2022018805A - Drive device of oil pump - Google Patents

Abstract

To provide a drive device of an oil pump which can supply a lubrication oil to a drive transmission system even if a failure occurs in an electric oil pump and inhibit rotation of the pump at excessive speed.SOLUTION: A drive device 100 of an oil pump 10 supplies a lubrication oil to a drive transmission system which transmits power of a power source and includes: an electric motor which rotates a rotor 32 of the oil pump; and a one-way clutch 40 which has a first rotary member 12, which is linked to the rotor, and a second rotary member 3, which is driven by the drive transmission system, connects a transmission path which transmits rotational force of the second rotary member to the first rotary member when a rotation speed of the second rotary member is higher than a rotation speed of the first rotary member, and disconnects the transmission path when the rotation speed of the second rotary member exceeds a predetermined threshold value.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a drive device for an oil pump.

Conventionally, an oil pump for supplying lubricating oil to a drive transmission system such as a transmission or a transfer mounted on a vehicle is known (see, for example, Patent Document 1).

The oil pump includes a mechanical oil pump that is driven by receiving power from a camshaft or a crankshaft, or an electric oil pump that is driven by receiving power from an electric motor.

The mechanical oil pump has a rotational resistance of the camshaft or the like as much as it receives power from the camshaft or the like.

On the other hand, since the electric oil pump does not receive power from the camshaft or the like, it does not become a rotational resistance of the camshaft or the like.

Japanese Unexamined Patent Publication No. 2009-162250

By the way, if the electric oil pump fails, it becomes difficult to supply lubricating oil to the drive transmission system, and there is a possibility that problems such as inability to travel may occur.

There is a demand for a fail-safe system that can supply lubricating oil to the drive transmission system even if the electric oil pump fails.

An object of the present disclosure is to provide a drive device for an oil pump capable of supplying lubricating oil to a drive transmission system and suppressing excessive high-speed rotation of the pump even when the electric oil pump fails. It is to be.

The oil pump drive device according to one aspect of the present disclosure is
A drive device for an oil pump that supplies lubricating oil to a drive transmission system that transmits the power of a power source.
The motor that rotates the rotor of the oil pump and
When it has a first rotating member interlocked with the rotor and a second rotating member driven by the drive transmission system, and the rotation speed of the second rotating member is higher than the rotation speed of the first rotating member. A one-way clutch that connects a transmission path that transmits the rotational force of the second rotating member to the first rotating member and disconnects the transmission path when the rotation speed of the second rotating member exceeds a predetermined threshold. To prepare for.

According to the present disclosure, even when the electric oil pump fails, it is possible to supply lubricating oil to the drive transmission system and suppress excessive high-speed rotation of the pump.

FIG. 1 is a diagram schematically showing a configuration of a vehicle including a drive device for an oil pump according to an embodiment of the present disclosure. FIG. 2 is a diagram schematically showing a configuration of a drive device for an oil pump according to the present embodiment. FIG. 3 is a diagram schematically showing an example of a one-way clutch. FIG. 4A is a partially enlarged view showing an example of a centrifugal disconnection type one-way clutch 40. FIG. 4B is a partially enlarged view showing the operation of the centrifugal disconnection type one-way clutch 40.

Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings.

First, the configuration of the vehicle including the drive device of the oil pump according to the embodiment of the present disclosure will be described.

The X-axis is drawn in FIG. The left-right direction in FIG. 1 is referred to as the X direction, the left direction is referred to as "X1 direction", "left direction" or "left side", and the right direction is referred to as "X2 direction", "right direction" or "right side". Further, the direction away from the X-axis is referred to as "centrifugal direction" or "centrifugal side". The direction toward the X-axis is referred to as "centripetal direction" or "centripetal side".

The vehicle is equipped with a transfer 1 (corresponding to the "drive transmission system" of the present disclosure), which is a mechanism for distributing the output of an internal combustion engine (engine, not shown; corresponding to the "power source" of the present disclosure) to the drive wheels. It is provided. The transfer 1 has a housing 2 and an output shaft 3. The housing 2 rotatably supports the output shaft 3 via a shaft support (not shown). The output shaft 3 is arranged along the X axis. The output shaft 3 is connected to the crank shaft (not shown) of the engine via a transmission (not shown). In this embodiment, the output shaft 3 is a mechanical pump shaft 20 (described later).

The oil pump 10 supplies lubricating oil to the shaft branch of the transfer 1, for example. The oil pump 10 is, for example, a trochoid type oil pump. The oil pump 10 includes a pump casing portion 11, an inner rotor 12 (corresponding to the “first rotating member” of the present disclosure), and an outer rotor 13.

The pump casing portion 11 has a tubular portion 11a that covers the output shaft 3 from the centrifugal direction. The left end of the tubular portion 11a is closed by the disc portion 11b. The right end of the tubular portion 11a is open. The tubular portion 11a accommodates the inner rotor 12 and the outer rotor 13. The tubular portion 11a rotatably supports the outer rotor 13.

The inner rotor 12 is arranged on the centripetal side of the outer rotor 13. The inner rotor 12 is arranged so as to mesh with the outer rotor 13.

A pump chamber (not shown) is formed between the inner rotor 12 and the outer rotor 13. A suction passage 15 and a discharge passage 16 are connected to the pump chamber. The suction passage 15 communicates with the lubricating oil storage portion (not shown). The discharge path 16 communicates with the hollow hole 21 of the mechanical pump shaft 20. As the inner rotor 12 rotates in one direction (for example, a clockwise direction when viewed from the X1 direction, hereinafter simply referred to as a "clockwise direction"), the pump chamber repeatedly expands and contracts. As a result, the lubricating oil in the lubricating oil storage portion is sucked into the pump chamber from the suction passage 15, and the lubricating oil in the pump chamber is discharged from the discharge passage 16 to the hollow hole 21.

FIG. 2 is a diagram schematically showing the configuration of the drive device 100 of the oil pump 10 according to the present embodiment. As shown in FIG. 2, the drive device 100 of the oil pump 10 includes a mechanical pump shaft 20, an electric motor 30, and a one-way clutch 40.

The mechanical pump shaft 20 is provided integrally with the output shaft 3. Therefore, the rotation speed of the mechanical pump shaft 20 (output shaft) fluctuates according to the vehicle speed and the rotation speed of the drive wheels.

The electric motor 30 includes a motor casing portion 31, a rotor 32, and a stator 33. The electric motor 30 is, for example, a reluctance motor in which the rotor 32 is composed of only a ferromagnetic iron core. In the reluctance motor, torque (reluctance torque) generated by the magnetic attraction force between the pole due to the rotating magnetic field of the stator 33 and the salient pole of the rotor 32 is used. The use of a reluctance motor has the following advantages. Since a permanent magnet is not used for the rotor 32, the load applied to the output shaft 3 from the rotor 32 side is small during fail-safe (when the inner rotor 12 is rotated by the output shaft 3). In addition, durability is improved. In addition, miniaturization can be achieved.

The motor casing portion 31 is arranged on the right side (X2 direction) of the pump casing portion 11. The motor casing portion 31 has an annular portion 31a that covers the output shaft 3 from the centrifugal direction. The right end opening of the annular portion 31a is closed by the disc portion 31b. The left end of the annular portion 31a is open.

The annular portion 31a accommodates the rotor 32 and the stator 33. The left end edge of the annular portion 31a and the right end edge of the tubular portion 11a are coupled to each other.

The rotor 32 is configured to be rotatable integrally with the inner rotor 12. The rotor 32 extends the inner rotor 12 in the right direction (X2 direction). Hereinafter, the rotor 32 may be referred to as an inner rotor 12.

The stator 33 is arranged on the centrifugal side of the inner rotor 12 (rotor 32). The stator 33 is fixed to the annular portion 31a.

A known one-way clutch is used for the one-way clutch 40. FIG. 3 is a diagram schematically showing an example of the one-way clutch 40. As shown in FIG. 3, the one-way clutch 40 has a first rotating member interlocked with the inner rotor 12, a second rotating member driven by the transfer 1, and a cam 45. Here, the first rotating member is the inner rotor 12. Further, the second rotating member is the output shaft 3. In the following description, the inner rotor 12 (first rotating member) may be referred to as an "outer ring". Further, the output shaft 3 (second rotating member) may be referred to as an "inner ring".

As shown in FIG. 3, the output shaft 3 (inner ring) is arranged at a position eccentric with respect to the inner rotor 12 (outer ring). The cam 45 is arranged between the output shaft 3 (inner ring) and the inner rotor 12 (outer ring).

In the one-way clutch 40, when the outer ring rotates in one direction with respect to the inner ring, the contact surface pressure between the cam 45 and the outer ring becomes low, and the cam 45 and the outer ring slide with each other. As a result, the torque transmission path from the inner ring to the outer ring is cut off. That is, the outer ring spins in one direction with respect to the inner ring. On the other hand, when the outer ring rotates in the other direction with respect to the inner ring, for example, when the outer ring stops rotating and the inner ring rotates in one direction, the contact surface pressure between the cam 45 and the outer ring increases, and the cam 45 and The outer ring does not slip on each other. As a result, the torque transmission path from the inner ring to the outer ring is connected. As a result, the outer ring continues to rotate in one direction via the one-way clutch 40.

Next, the operation of the drive device 100 of the oil pump 10 in a normal state will be described.
When the ignition switch is turned on, the electric motor 30 is energized and the inner rotor 12 (outer ring) rotates in one direction (clockwise) faster than the output shaft 3 (inner ring). As a result, the torque transmission path from the output shaft 3 (inner ring) to the inner rotor 12 (outer ring) is cut off. That is, the inner rotor 12 (outer ring) rotates in one direction at a predetermined rotation speed, and lubrication by the oil pump 10 is started.

Even when the vehicle starts moving forward, as shown in FIG. 3, the inner rotor 12 (outer ring) rotates in one direction at a rotation speed that is + α larger than the rotation speed of the output shaft 3 (inner ring). As a result, the torque transmission path from the output shaft 3 (inner ring) to the inner rotor 12 (outer ring) is cut off. That is, lubrication by the oil pump 10 is continued.

If the electric motor 30 fails, the electric motor 30 makes it impossible to rotate the inner rotor 12 (outer ring) in one direction (clockwise direction). However, when the vehicle is moving forward, the output shaft 3 (inner ring) rotates in one direction (clockwise direction). Therefore, the inner rotor 12 rotates in the other direction (counterclockwise direction) with respect to the output shaft 3. As a result, the torque transmission path from the output shaft 3 to the inner rotor 12 is connected. As a result, it becomes possible to continue the rotation of the inner rotor 12 in one direction. As described above, even if the electric motor 30 fails, lubrication by the oil pump 10 can be continued.

When the torque transmission path from the output shaft 3 (inner ring) to the inner rotor 12 (outer ring) is connected, the rotation speed of the inner rotor 12 increases according to the rotation speed of the output shaft 3. As a result, the oil pump 10 may rotate at an excessively high speed.

The one-way clutch 40 in the present embodiment is a centrifugal disconnection type one-way clutch. FIG. 4A is a partially enlarged view showing an example of a centrifugal disconnection type one-way clutch 40. The centrifugally detachable one-way clutch 40 has a spring 46 in addition to an inner rotor 12 (outer ring), an output shaft 3 (inner ring), and a cam 45.

FIG. 4A shows the line L1 in the centrifugal direction, which is the direction away from the center of rotation. As shown in FIG. 4A, the contact position A of the cam 45 with the outer ring and the center of gravity position G of the cam 45 are not arranged on the line L1 in the centrifugal direction. When centrifugal force acts, the cam 45 receives a clockwise moment around the contact position A. Further, the cam 45 receives a moment due to the spring 46.

When the rotation speed of the inner ring is equal to or less than a predetermined threshold value, the moment due to the centrifugal force does not exceed the moment due to the spring 46. As a result, the cam 45 does not rise and is in contact with the inner ring raceway surface.

FIG. 4B is a partially enlarged view showing the operation of the centrifugal disconnection type one-way clutch 40. As shown in FIG. 4B, when the rotation speed of the inner ring exceeds a predetermined threshold value, the moment due to the centrifugal force exceeds the moment due to the spring 46, so that the cam 45 floats and separates from the inner ring raceway surface. As a result, the torque transmission path from the inner ring to the outer ring is cut off. As a result, excessive high-speed rotation of the pump can be suppressed.

As described above, in the drive device 100 of the oil pump 10 according to the present embodiment, the electric motor 30 for rotating the inner rotor 12 of the oil pump 10, the output shaft 3 of the transfer 1, and the rotation speed of the output shaft 3 are the same. When the rotation speed of the inner rotor 12 is higher than the rotation speed of the inner rotor 12, the rotational force of the output shaft 3 is transmitted to the inner rotor 12, and when the rotation speed of the output shaft 3 exceeds a predetermined threshold value, the torque from the output shaft 3 to the inner rotor 12 is reached. It is provided with a one-way clutch 40 that disconnects the transmission path.

With the above configuration, when the electric motor 30 fails, the torque transmission path from the output shaft 3 to the inner rotor 12 is connected. This makes it possible to operate the oil pump 10. As described above, even if the electric motor 30 fails, the operation of the oil pump 10 can be continued, so that it is possible to avoid the occurrence of problems such as inability to travel.

Further, when the rotation speed of the output shaft 3 exceeds a predetermined threshold value, the moment due to the centrifugal force exceeds the moment due to the spring 46, so that the cam 45 floats and separates from the inner ring raceway surface. As a result, the torque transmission path from the output shaft 3 to the inner rotor 12 is cut off. As a result, excessive high-speed rotation of the oil pump 10 can be suppressed. Further, in the normal state, it is not necessary to make the rotation speed of the inner rotor 12 faster than the rotation speed of the output shaft 3, so that the oil pump 10 can be driven independently of the rotation of the output shaft 3. As a result, it becomes possible to suppress an excessive amount of oil supplied to the oil pump 10, and a relief valve for protecting the oil pump 10 becomes unnecessary.

Further, in the above embodiment, the mechanical pump shaft 20 is provided integrally with the output shaft 3. This makes it possible to reduce the size of the drive device 100.

In the drive device 100 of the oil pump 10 according to the above embodiment, the mechanical pump shaft 20 is arranged coaxially with the output shaft 3 of the transfer 1, but the present disclosure is not limited to this, and for example, the mechanical pump shaft 20 is used. , It may be arranged on a shaft different from the output shaft 3 and connected to the output shaft 3 via an endless belt, a chain, or the like. At that time, for example, the mechanical pump shaft 20 may be connected to the inner rotor 12, the one-way clutch 40 may be arranged coaxially with the output shaft 3, and the mechanical pump shaft 20 may be connected to the output shaft 3 via the endless belt and the one-way clutch 40. ..

Further, in the drive device 100 of the oil pump 10 in the above embodiment, the transfer 1 is mentioned as a target for supplying lubrication, but the present disclosure is not limited to this, and for example, a transmission may be used. Further, the applicable range of the drive device 100 of the oil pump 10 in the above embodiment is not limited to the vehicle.

In addition, the above embodiments are merely examples of the embodiment of the present disclosure, and the technical scope of the present disclosure should not be construed in a limited manner by these. That is, the present disclosure can be implemented in various forms without departing from its gist or its main characteristics.

The drive device 100 of the oil pump 10 of the present disclosure is required to supply lubricating oil to the drive transmission system and suppress excessive high-speed rotation of the pump even when the electric oil pump fails. It is useful as a lubrication system for vehicles.

1 Transfer 2 Housing 3 Output shaft 10 Oil pump 11 Pump casing part 11a Cylindrical part 11b Disc part 12 Inner rotor 13 Outer rotor 15 Suction path 16 Discharge path 20 Mechanical pump shaft 30 Electric motor 31 Motor casing part 31a Circular part 31b Disc Part 32 Rotor 33 Stator 40 One-way clutch 45 Cam 46 Spring 100 Drive

Claims (3)

A drive device for an oil pump that supplies lubricating oil to a drive transmission system that transmits the power of a power source.
The motor that rotates the rotor of the oil pump and
When it has a first rotating member interlocked with the rotor and a second rotating member driven by the drive transmission system, and the rotation speed of the second rotating member is higher than the rotation speed of the first rotating member. A one-way clutch that connects a transmission path that transmits the rotational force of the second rotating member to the first rotating member and disconnects the transmission path when the rotation speed of the second rotating member exceeds a predetermined threshold. Equipped with
Oil pump drive. The second rotating member is arranged coaxially with the output shaft of the drive transmission system.
The oil pump drive device according to claim 1. The oil pump drive device according to claim 2, wherein the second rotating member is the output shaft.

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