JPH11107936A - Hydraulic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high output though forming in compactness, in a hydraulic unit including a hydraulic pump driven to rotate in a single direction of rotation. SOLUTION: A hydraulic unit is applied to a power steering device A mounted in a vehicle. In one end 11 of a rotary shaft 10 of a hydraulic pump 7, a first gear member 36 is provided able to integrally rotate, the first gear member 36 is connected through one-way clutch 15 to an output shaft 23 connected to an engine. A second gear member 37 meshed with the first gear member 36 is connected through a second one-way clutch 16 to a rotary shaft 17 of an electric motor 14. At low speed running time, the oil hydraulic pump 7 is driven by only the electric motor 14, and at high speed running time, the oil hydraulic pump 7 is driven by only the engine 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hydraulic unit including a hydraulic pump.

[0002]

2. Description of the Related Art An electric pump unit in which a pump and an electric motor are integrated is widely used in automobiles, construction machines, and the like as a compact and highly energy-efficient hydraulic power source. For example, in an automobile, there is a power steering device (power steering device) for reducing the operation force of a steering wheel (steering wheel) using the above-described electric pump unit. In this case, by controlling the drive current of the electric motor that rotationally drives the hydraulic pump, the hydraulic pressure supplied from the hydraulic pump to the power cylinder as the hydraulic actuator is controlled, thereby reducing the steering wheel operating force.

[0003]

Incidentally, there is a case where the above hydraulic pump is required to have a high output. In this case, it is necessary to increase the capacity of the electric motor that drives the hydraulic pump, which increases the manufacturing cost. In addition, when the above-described electric motor having a large capacity is driven by a low-potential battery mounted on a vehicle, the current may be excessively large and durability and reliability may be reduced. For this reason, the capacity of the electric motor cannot be increased so much, and as a result, it has been difficult to increase the output of the hydraulic pump.

Accordingly, an object of the present invention is to provide a hydraulic unit which is compact and has a high output.

[0005]

According to a first aspect of the present invention, there is provided a hydraulic unit, comprising: a hydraulic pump rotated in one rotational direction; and a rotating shaft of the hydraulic pump. To a first drive source and a second drive source. The transmission mechanism is connected to the first drive source via a first one-way clutch. And a second coupling connected to the second driving source via a second one-way clutch, and one of the couplings is connected to the hydraulic pump. It is characterized by being integrally rotatably connected on the same axis of the rotating shaft.

[0006] In this case, since the two connected bodies that are drivingly connected to each other are drivingly connected to the drive source on the higher rotation speed side, the hydraulic pump can be connected to the higher rotation speed side via at least one connection body. It is drivingly connected to the driving source. With a simple structure using a pair of one-way clutches and a pair of coupling bodies, the drive source can be selectively switched, and energy saving can be achieved. In particular, when the drive source is an electric motor, the drive source can be switched by driving and stopping the electric motor. In addition, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of each drive source, and the degree of design freedom is high.

According to a second aspect of the present invention, there is provided a hydraulic unit comprising: a hydraulic pump rotated in one rotation direction; and a transmission mechanism for connecting a rotary shaft of the hydraulic pump to first and second driving sources. The transmission mechanism is connected to a first drive source via a first one-way clutch via a first one-way clutch, and is connected to the first connection body via an intermediate member so as to be able to transmit drive. A second connecting member connected to a second driving source via a second one-way clutch, wherein the intermediate member is connected so as to be integrally rotatable coaxially with a rotary shaft of the hydraulic pump. It is a feature.

[0008] In this case, since the two connecting bodies which are drivingly connected to each other via the intermediate member are drivingly connected to the driving source on the higher rotation speed side, the hydraulic pump can be connected via one of the connecting bodies or The drive connection to the drive source on the higher rotation speed side is made via both the connection body and the intermediate body. With a simple structure using a pair of one-way clutches, a pair of coupling bodies and an intermediate body, the drive source can be switched alternatively, and energy saving can be achieved. In particular, when the drive source is an electric motor, the drive source can be switched by driving and stopping the electric motor. In addition, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of each drive source, and the degree of design freedom is high.

The hydraulic unit according to the third aspect is the first aspect.
Or 2, an electric motor is provided as a second drive source, a first one-way clutch is connected to an output shaft connected to a vehicle drive source as the first drive source, and the second one-way clutch is connected to the electric motor. It is characterized by being connected to an output shaft of a motor. In this case, when the rotation speed of the output shaft connected to the drive source of the vehicle is low during low-speed traveling, the electric motor can be used as the driving source. Can be. Further, the hydraulic unit can be easily configured by incorporating the hydraulic pump, the transmission mechanism, and the electric motor into the vehicle without changing the layout on the vehicle side. Further, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of the electric motor, and the degree of design freedom is high.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a schematic configuration of a power steering device including a hydraulic unit according to one embodiment of the present invention. Referring to FIG. 1, a hydraulic pump 7 and rotation from a required drive source such as an electric motor of a hybrid electric vehicle or an engine including an internal combustion engine are transmitted to the power steering apparatus A, for example. A hydraulic unit U including a pair of one-way clutches 15 and 16 for power transmission, and a power cylinder 1 supplied with hydraulic pressure by the hydraulic unit U are provided.

The power cylinder 1 is connected to, for example, a rack shaft 3 included in a steering mechanism 2.
Then, when a rotational force is applied to the steering shaft 5 by the steering wheel 4 and the rack shaft 3 is moved left and right by the pinion gear 6 to perform steering, the power cylinder 1 assists the movement of the rack shaft 3. work.
That is, the power cylinder 1 generates a steering assist force at the time of steering in cooperation with the steering wheel 4. In FIG. 1, reference numeral 31 denotes a tie rod connected to an end of the rack shaft 3, and reference numeral 32 denotes a wheel.

The power cylinder 1 is driven by hydraulic oil supplied from a hydraulic pump 7. Specifically, the power cylinder 1 is operated by supplying hydraulic oil to one of the oil chambers 1a (or 1b) via the electromagnetic control valve 8 and one of the oil passages 29 (or 30). I do.
At this time, the hydraulic oil discharged from the other oil chamber 1b (or 1a) is returned to the hydraulic pump 7 via the corresponding oil passage 30 (or 29), the control valve 8, and the return passage 28 (or 27). It is.

The input applied to drive the hydraulic pump 7 is supplied from the electric motor 14 during low-speed running, and is used to drive the vehicle during high-speed running, by the functions of one-way clutches 15 and 16 described later. The source is, for example, from the engine 13 side.
Examples of the drive source of the vehicle include an electric motor of a hybrid electric vehicle in addition to the above-described engine.

The hydraulic pump 7 is composed of a gear pump, a vane pump or another known rotary pump, and has a rotary shaft 10 protruding from both sides of a pump body 9. One end 11 of the rotary shaft 10 is connected to a transmission mechanism 12. Engine 1 through
The drive side is alternatively connected to the third side and the electric motor 14 side. The transmission mechanism 12 is provided with a first gear member 36 as a first connecting member provided integrally with the one end 11 of the rotary shaft 10 of the hydraulic pump 7 so as to be integrally rotatable, and a first gear member 36 meshed with the first gear member 36. The second gear member 37 is provided as a second connected body.

The first gear member 36 is connected via a first one-way clutch 15 to an output shaft 23 arranged coaxially with the rotary shaft 10, and this output shaft 23 serves as a transmission mechanism. Is connected to the output shaft 20 of the engine 13 via the speed increasing mechanism 18. That is, the first gear member 36
Is connected to an output shaft 23 connected to the engine 13 via a first one-way clutch 15. A bearing 19 rotatably supports the output shaft 23 connected to the engine. The first gear member 36 may be formed integrally with the one end 11 of the rotary shaft 10 of the hydraulic pump 9, or as a separate member, integrally rotatable with the one end 11 of the rotary shaft 10 by, for example, spline connection or screw connection. It may be attached.

On the other hand, the second gear member 37 is connected via a second one-way clutch 16 to a rotating shaft 17 as an output shaft of the electric motor 14. The first gear member 36 is connected to the output shaft 23 and the second gear member 37 is connected to the electric motor 14.
Cylindrical portions 38, 39 extending toward the rotating shaft 17 of the
The one-way clutches 15 and 16 are accommodated and held in the cylindrical portions 38 and 39, respectively.

The one-way clutches 15 and 16 transmit the rotation of the engine 13 and the electric motor 14 as drive sources only in the direction of rotation of the rotary shaft 10, and include an output shaft 23 and an electric motor connected to the engine. Among the fourteen rotating shafts 17, the one having a higher rotation speed is to be drive-coupled to the rotation shaft 10 of the hydraulic pump 7, and the one having a lower rotation speed is to be disconnected from the rotation shaft 10 for driving. become. Specifically, when the rotation speed of the rotating shaft 17 of the electric motor 14 is relatively high, the rotation of the rotating shaft 17 of the electric motor 14 is controlled by the second one-way clutch 16, the second gear member 37, and the first Is transmitted to the rotating shaft 10 of the hydraulic pump 7 through the gear member 36 of FIG. On the other hand, when the rotation speed of the output shaft 23 connected to the engine is relatively high, the output shaft 2
3 is transmitted to the rotating shaft 10 of the hydraulic pump 7 via the first one-way clutch 15 and the first gear member 36.

As the first one-way clutch 15, for example, as shown in FIG.
A plurality of recesses are formed in the circumference of the inner peripheral surface of the rotating shaft 10, and a wedge-shaped space 33 is provided between each recessed portion and the outer peripheral surface of the end portion 11 of the rotating shaft 10. A cylindrical roller 34 slidably in contact with the outer peripheral surface of the end portion 11 is accommodated, and each cylindrical roller 34 is elastically urged toward the narrow side of the wedge-shaped space 33 by an elastic member 35. The second one-way clutch 16 may have a similar configuration.

The speed increasing mechanism 18 includes a first gear 21 attached to an output shaft 20 of the engine 13 so as to be integrally rotatable.
And a second gear 22 that meshes with the first gear 21 and that is rotatably attached to an intermediate portion of an output shaft 23 connected to the engine. The electric motor 14 is controlled by a controller 24. The controller 24 is connected to a vehicle speed sensor 25 for detecting the running speed of the vehicle, and a steering sensor 26 for detecting the direction and amount of rotation of the steering wheel 4. This steering sensor 26 is constituted by, for example, a DC generator,
It has a positive or negative sign according to the rotation direction of the steering wheel 4 and outputs an electric signal proportional to the rotation speed and the rotation amount.

The controller 24 controls a solenoid (not shown) of the control valve 8 in accordance with an output signal from the steering sensor 26, and controls driving and stopping of the electric motor 14 in accordance with a vehicle speed signal from the vehicle speed sensor 25. Thus, the drive current of the electric motor 14 is controlled. Specifically, when the vehicle speed exceeds a predetermined threshold, the driving of the electric motor 14 is stopped. The above threshold value is preferably set to a predetermined speed in a range of 20 to 30 km / h. Actually, it is preferable to stop the electric motor 14 at a speed as low as possible in order to save energy and to improve the durability of the electric motor.

According to the above embodiment, the pair of one-way clutches 15 and 16 and the pair of gear members 3
By adopting a simple structure using 6, 37, a compact hydraulic unit U can be achieved, and a high output can be obtained while achieving energy saving by smoothly switching between a pair of drive sources 13, 14 alternatively. Can be. In addition, by changing the transmission gear ratio between the gear members 36 and 37, the specifications of the hydraulic pump 7 can be changed without changing the specifications of the respective driving sources 13 and 14, and the degree of freedom of design can be increased. high.

Also, by using the electric motor 14 as a drive source during low-speed running, a stable hydraulic pressure can be generated. Therefore, in a steering operation such as stationary operation during low-speed running, the power steering device A becomes stable. A steering assist force can be generated. On the other hand, when the vehicle speed increases and the engine 13 which is the driving source of the vehicle can obtain a sufficient hydraulic pressure generated by the hydraulic pump, the electric motor 14
To stop. This can save energy and
A small and inexpensive electric motor 14 can be adopted,
Moreover, the durability of the electric motor 14 can be improved.

The hydraulic unit U is connected to the hydraulic pump 7
In the case of a unit including the electric motor 14 in addition to the transmission mechanism 12 and the transmission mechanism 12, the hydraulic pump 7, the transmission mechanism 12 and the electric motor 14 can be easily assembled into the vehicle without changing the layout on the vehicle side. Unit U can be configured. Also in this case, the specifications of the hydraulic pump 7 can be changed without changing the specifications of the electric motor 14 by changing the transmission gear ratio between the gear members 36 and 37 as the connecting body. High degree of freedom.

Further, since the rotation of the engine 13 is increased in speed through the speed increasing mechanism 18 and transmitted to the rotary shaft 10 of the hydraulic pump 7, even if the hydraulic pump 7 is small,
A high output can be obtained by increasing the discharge amount per unit time.
The capacity of the electric motor 14 for driving such a small hydraulic pump 7 can be reduced, so that it can be inexpensive and have excellent durability.

FIG. 3 shows another embodiment of the present invention. With reference to FIG.
An intermediate gear member 40 as an intermediate member is interposed between the gear member 36 and the second gear member 37, and a driving force is applied between the first and second gear members 36 and 37 via the intermediate gear member 40. To be communicated. Also, the intermediate gear member 4
Numeral 0 is coaxially connected to the rotary shaft 10 of the hydraulic pump 7 so as to be integrally rotatable. Other configurations are the same as those of the embodiment of FIG. 1, and therefore, the same reference numerals are given to the drawings and the description thereof will be omitted.

According to the present embodiment, the intermediate gear member 40
Is added, the structure becomes slightly more complicated than that of the embodiment of FIG. 1, but the same operation and effect as the embodiment of FIG. 1 can be obtained. Also, by changing the transmission gear ratio between the first and second gear members 36 and 37 and the intermediate gear member 40, the specifications of the hydraulic pump 7 can be changed without changing the specifications of the electric motor 14. It has a high degree of freedom in design.

The present invention is not limited to the above embodiments. For example, in each of the above embodiments, the transmission mechanism is configured to include a gear mechanism having a pair of gear members. It can be configured to include a belt mechanism, a traction drive type planetary roller mechanism, and the like. When using a pulley / belt mechanism,
The pair of connecting members is constituted by a pair of pulley members, and when a roller mechanism is employed, the pair of connecting members is constituted by a pair of roller members.

Further, in each of the above embodiments, after the drive source is switched to the engine side as the vehicle speed increases,
Although the electric motor 14 is stopped, it is also possible to switch the drive source by driving and stopping the electric motor 14. Further, in each of the above embodiments, the present invention is applied to the power steering device using the hydraulic actuator as a power cylinder, but can be applied to another hydraulic power device mounted on a vehicle. That is, the hydraulic actuator is constituted by a power unit constituted by a hydraulic cylinder for operating an AT clutch, and the hydraulic actuator is constituted by a hydraulic cylinder for operating a drive distribution switching clutch for front and rear wheels in a four-wheel drive vehicle. It can be applied to a power plant. Also in these power units, it is possible to obtain a compact and sufficient power even at a low speed while ensuring the durability of the electric motor.

In addition, various changes can be made within the scope of the present invention.

[0030]

According to the first aspect of the present invention, a compact structure having a simple structure using a pair of one-way clutches and a pair of coupling bodies is achieved, and the driving source is selectively switched to achieve high energy saving. You can get the output. In addition, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of each drive source, and the degree of design freedom is high.

According to the second aspect of the present invention, a compact structure having a simple structure using a pair of one-way clutches, a pair of connecting bodies and an intermediate body is achieved, and the driving source is selectively switched to achieve energy saving. High output can be obtained. In addition, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of each drive source, and the degree of design freedom is high.

According to the third aspect of the present invention, a stable hydraulic pressure can be generated by using the electric motor as a drive source during low-speed running. When a sufficient hydraulic pressure generated by the hydraulic pump is obtained by the driving source of the vehicle, the electric motor is stopped. As a result, energy saving can be achieved, and a small and inexpensive electric motor can be employed, and the durability of the electric motor can be improved. Further, the hydraulic unit can be easily configured by incorporating the hydraulic pump, the transmission mechanism, and the electric motor into the vehicle without changing the layout on the vehicle side. Further, by changing the transmission ratio between the connected bodies, the specifications of the hydraulic pump can be changed without changing the specifications of the electric motor, and the degree of design freedom is high.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a power steering device to which a hydraulic unit according to an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional view of a main part of the one-way clutch.

FIG. 3 is a schematic view of a main part of a hydraulic unit as another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 power cylinder (hydraulic actuator) 7 hydraulic pump 10 rotary shaft 12 transmission mechanism 13 engine (drive source) 14 electric motor (drive source) 15 first one-way clutch 16 second one-way clutch 17 rotary shaft (output shaft) Reference Signs List 23 Output shaft connected to engine 36 First gear member (first connection member) 37 Second gear member (second connection member) 40 Intermediate gear member U Hydraulic unit A Power steering device (power device)

Claims (3)

[Claims] 1. A hydraulic pump rotated in one rotation direction,
A transmission mechanism for connecting a rotary shaft of the hydraulic pump to first and second drive sources, wherein the transmission mechanism is connected to the first drive source via a first one-way clutch. And a second driving source connected to the first connecting body so as to be able to transmit the drive.
And a second connecting member connected via a one-way clutch, wherein one of the connecting members is connected so as to be integrally rotatable coaxially with the rotating shaft of the hydraulic pump. . 2. A hydraulic pump rotated in one rotation direction,
A transmission mechanism for connecting a rotary shaft of the hydraulic pump to first and second drive sources, wherein the transmission mechanism is connected to the first drive source via a first one-way clutch. And a second connecting body connected to the first connecting body via an intermediate member so as to be able to transmit a drive and connected to a second driving source via a second one-way clutch. A hydraulic unit, wherein the intermediate member is connected so as to be integrally rotatable coaxially with a rotary shaft of a hydraulic pump. 3. An electric motor is provided as a second drive source, a first one-way clutch is connected to an output shaft connected to a vehicle drive source as the first drive source, and the second one-way clutch is connected to the output shaft. 3. The hydraulic unit according to claim 1, wherein the hydraulic unit is connected to an output shaft of the electric motor.