JPH09207793A - Power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce loss and consumption of energy by controlling driving and stopping of a hydraulic pump putting on and off a clutch means by pressure of a hydraulic passage. SOLUTION: A pulley (drive means) 4 connected to an internal combustion engine 6 and a hydraulic pump 7 to be rotationally driven by this pulley 4 are provided. An accumulator 33 is provided in a hydraulic passage 31 to guide discharge oil of this hydraulic pump 7 to an actuator 1 through a check valve 32. An electromagnetic clutch (clutch means) 34 to control driving and stopping of the hydraulic pump 7 by being put on and off in accordance with pressure of the hydraulic passage 31 on the downstream side of the check valve 32 is provided between the pulley 4 and the hydraulic pump 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering apparatus which is suitable for use in automobiles and the like.

[0002]

2. Description of the Related Art A power steering device for supplying steering oil to an actuator provided in a steering mechanism to obtain a steering assisting force is used in automobiles and the like in order to make steering operation lighter. A proposed power steering device has been proposed.

For example, in Japanese Patent Laid-Open No. 61-85272, an accumulator is provided in a hydraulic passage between an actuator composed of a control valve and a power cylinder and a hydraulic pump driven by an electric motor. A power steering device is disclosed in which the pressure in a hydraulic passage is detected by a pressure sensor, and a controller to which a detection signal of the pressure sensor is input controls the driving / stopping of the electric motor.

In this improved power steering system, the hydraulic pump is driven by the electric motor at the time when the pressure sensor detects the pressure drop in the hydraulic passage, so that the hydraulic pump does not always rotate, thus saving power. Energy can be saved. Further, by preliminarily accumulating the operating oil pressure in the accumulator, it is possible to eliminate the problem that the discharge capacity becomes insufficient due to the rising characteristics of the hydraulic pump at the time of starting, such as during a sudden steering operation.

[0005]

However, in the above-mentioned conventional example, since the hydraulic pump for hydraulic oil is rotationally driven by the electric motor, in the case of a vehicle equipped with an internal combustion engine, the drive of the engine is performed. Energy is reduced not only by the operating efficiency of the electric motor but also by the power generation efficiency of the alternator, which may result in a large energy loss. Further, since the electric motor consumes a large amount of power, there is a risk that the amount of energy consumed, that is, the fuel consumption, will deteriorate.

The present invention has been devised in view of the above conventional circumstances, and an object of the present invention is to provide a power steering device with less energy loss and consumption.

[0007]

Therefore, the invention according to claim 1 is connected to an internal combustion engine in a power steering apparatus for supplying and discharging hydraulic oil to and from an actuator in accordance with a steering torque of a steering shaft to obtain a steering assisting force. And a hydraulic pump that is rotationally driven by the driving unit, a hydraulic passage that guides the discharge oil of the hydraulic pump to the actuator through a check valve, and a hydraulic passage that is downstream of the check valve. An accumulator provided between the drive means and the hydraulic pump, and a clutch means for contacting and separating according to the pressure of the hydraulic passage downstream of the check valve to control the drive / stop of the hydraulic pump. , Is provided.

According to a second aspect of the invention, the clutch means having the structure according to the first aspect is electromagnetically controlled by a pressure switch that operates in accordance with the pressure in the hydraulic passage downstream of the check valve. It is configured as a clutch.

Here, as the driving means, a pulley which is rotationally driven by an internal combustion engine via a belt can be applied. In addition to using a chain, various driving means that can be constantly driven to rotate by an internal combustion engine can be adopted.

As the clutch means, various clutches such as a hydraulic clutch and a mechanical clutch can be applied in addition to the electromagnetic clutch, and this clutch means is used in accordance with the pressure in the hydraulic passage downstream of the check valve. It is possible to approach and separate. That is, means for monitoring the pressure in the hydraulic passage on the downstream side of the check valve, for example, a pressure switch, a pressure sensor, etc., is provided, and the clutch means is controlled to engage and disengage based on the detection signals of these monitoring means.

Since an accumulator is provided in the hydraulic passage on the downstream side of the check valve, it is also within the scope of the present invention to monitor the pressure of the accumulator and control the engagement / disengagement of the clutch means.

In the power steering apparatus of the present invention, when the pressure in the hydraulic passage downstream of the check valve is smaller than the predetermined pressure, the clutch means is connected to transmit the rotational driving force from the driving means to the hydraulic pump. Then, this hydraulic pump is rotationally driven.

The hydraulic oil discharged by the operation of the hydraulic pump is supplied to the actuator and the accumulator. The hydraulic oil supplied to the actuator is used to appropriately exert a steering assisting force. On the other hand, the hydraulic oil supplied to the accumulator is accumulated in the accumulator until it reaches a predetermined pressure.

When the accumulated pressure of the accumulator, that is, the pressure of the hydraulic passage downstream of the check valve reaches a predetermined pressure, the clutch means releases the connection according to this pressure,
As a result, the rotational drive of the hydraulic pump is stopped. In this state, hydraulic oil is not supplied from the hydraulic pump, but the hydraulic passage on the downstream side of the check valve is blocked from communication with the upstream side by the check valve, and the hydraulic passage on the downstream side of the check valve is closed. Is given pressure by the accumulator. For this reason, at the time of sudden steering or the like, the hydraulic oil accumulated in the hydraulic passage on the downstream side of the check valve is promptly supplied to the actuator, and a smooth steering assist operation is achieved.

The accumulated energy is consumed by the operation of the actuator, and when the pressure in the hydraulic path downstream of the check valve decreases, the clutch means is reconnected.
As a result, the hydraulic pump is driven again, and the discharge oil is supplied to the hydraulic passage.

Therefore, the hydraulic pump does not always rotate and energy can be saved. Further, by preliminarily accumulating the working hydraulic pressure in the accumulator, it is possible to eliminate the problem that the discharge capacity becomes insufficient due to the rising characteristics of the hydraulic pump at the time of start-up, such as during sudden steering.

Further, since the clutch means is brought into contact with or separated from the hydraulic passage by the pressure in the hydraulic passage to control the drive / stop of the hydraulic pump, the drive of the hydraulic pump can be controlled without using an electric motor, resulting in energy loss and consumption. It is possible to obtain a power steering device with less power consumption.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory view of a power steering system showing an embodiment of the invention. In the figure, reference numeral 1 is an actuator of a power steering device, and this actuator 1 includes a center-closed type control valve 2 and a power cylinder 3.

Reference numeral 4 denotes a pulley as a driving means. The pulley 4 is connected to an internal combustion engine 6 via a belt 5 and is constantly rotated by the internal combustion engine 6.

Reference numeral 7 is a hydraulic pump which is rotationally driven by a pulley 4 as the driving means.
In this embodiment, the recess 9 of the pump housing 8
A cam ring 12 and a side plate 13, which accommodate a rotor 11 in which a plurality of vanes 10 are mounted so as to be retractable and retractable in a substantially radial direction, are housed therein.
A vane pump having a structure in which the openings of the above are covered with a cover plate 14 is shown. This hydraulic pump (vane pump) 7
Has a pump chamber 15 formed between adjacent vanes of the plurality of vanes 10.
The rotation changes the volume thereof, and a suction section is formed at a portion where the volume increases due to this change, and a discharge section is formed at a portion where the volume decreases.

Reference numeral 16 is a suction passage of the hydraulic pump 7, and the suction passage 16 communicates with a suction section of the pump chamber 15. Reference numeral 17 is a flow control valve.
Is configured to control a discharge flow rate from the hydraulic pump 7 by recirculating a part of the hydraulic oil introduced from a discharge passage (not shown) communicating with the discharge section of the pump chamber 15 to the suction passage 16. A suction pipe 18 is attached to the pump housing 8, and the suction pipe 18 connects the suction passage 16 and the oil storage tank 19. 20
Is a drive shaft connected to the rotor 11 and rotationally drives the rotor 11, 21 is a bearing arranged between the drive shaft 20 and the pump housing 8, and 22 is also a seal member.

Reference numeral 31 is a hydraulic passage for guiding the discharge oil of the hydraulic pump 7 to the actuator 1, and a flow rate controlled by the flow control valve 17 is introduced into the hydraulic passage 31. A check valve 32 that allows the hydraulic pump 7 to flow to the actuator 1 and blocks the reverse flow is provided in the middle of the hydraulic passage 31. Further, the check valve 32
An accumulator 33 capable of maintaining a predetermined pressure in the hydraulic passage 31 is provided in the hydraulic passage 31 on the downstream side.

Reference numeral 34 is an electromagnetic clutch (clutch means) provided between the pulley 4 as the driving means and the hydraulic pump 7. The electromagnetic clutch 34 corresponds to the pulley 4
To the friction surface 36 of the rotor 35, and the armature 37 connected to the drive shaft 20. The armature 37 is attracted to the friction surface 36 of the rotor 35. The electromagnetic coil 38 is used as a main element.

The rotor 35 has a U-shaped cross section and has a substantially annular shape as a whole. The pulley 4 is fixed to the outer peripheral side of the rotor 35, while the inner peripheral side of the rotor 35 is fixed to the holder 39 fixed to the pump housing 8. , Is rotatably connected via a bearing 40. Reference numeral 41 is a screw for fixing the holder 39 to the pump housing 8.

The armature 37 has a flat plate shape and is arranged with a slight gap between the armature 37 and the friction surface 36 of the rotor 35. Around the outer peripheral end of the armature 37, flexible strap plates 42 are provided at a plurality of positions. Drive plate 4
Connected to 3. The inner peripheral base portion 44 of the drive plate 43 is non-rotatably fixed to the drive shaft 20 by a bolt 45 and a key 46.

The electromagnetic coil 38, which is fixed to the holder 39, is housed and arranged inside the U-shape of the rotor 35 with a predetermined gap.

Reference numeral 47 denotes a dual pressure switch. The pressure switch 47 monitors the pressure in the hydraulic passage 31 on the downstream side of the check valve 32 via the detection oil passage 48, and in accordance with this pressure, the electromagnetic clutch is detected. 34 is controlled to approach or separate. That is, the pressure switch 47 is provided in the middle of the power supply circuit 50 from the power supply 49 to the electromagnetic coil 38, and when the pressure in the hydraulic passage 31 guided from the detection oil passage 48 is higher than a predetermined value, the power supply circuit. 50 is opened to cut off the supply of the exciting current to the electromagnetic coil 38, while the pressure in the hydraulic passage 31 is lower than a predetermined value, the power supply circuit 5
0 is closed and an exciting current is supplied to the electromagnetic coil 38. That is, the pressure switch 47 is connected to the electromagnetic coil 38.
By controlling the power supply to the electromagnetic clutch 34, the electromagnetic clutch 34 is controlled to be in contact with or separated from the electromagnetic clutch 34.

The end of the power supply circuit 50, that is, one end of the power supply 49 and one end of the electromagnetic coil 38 are grounded.

Next, the operation of the power steering device having such a configuration will be described.

First, the pulley 4 as the driving means is
The internal combustion engine 6 constantly drives the belt 5 to rotate, and the rotor 35 fixed to the pulley 4 also rotates. In this state, when the pressure in the hydraulic passage 31 downstream of the check valve 32, which is guided from the detection oil passage 48 to the pressure switch 47, is lower than a predetermined value, the pressure switch 47 closes the power supply circuit 50. An exciting current is supplied from the power source 49 to the electromagnetic coil 38. As a result, the armature 37 is attracted, adsorbed to the friction surface 36 of the rotating rotor 35, and the electromagnetic clutch 34 is connected. As a result, the rotational drive force from the pulley 4 is transmitted to the drive shaft 20 via the rotor 35, the armature 37, the strap plate 42, and the drive plate 43, and the hydraulic pump 7 is rotationally driven.

When the hydraulic pump 7 is rotationally driven, hydraulic oil is sucked from the oil storage tank 19 into the pump chamber 15 in the suction section through the suction pipe 18 and the suction passage 16, and then the pump chamber in the discharge section. Flow control valve 1 from inside 15
7 is introduced into the hydraulic passage 31. This hydraulic passage 3
The hydraulic fluid discharged to No. 1 is guided to the accumulator 33 and the actuator 1 via the check valve 32.

The hydraulic oil guided to the actuator 1 is consumed in order to exert the steering assisting force when the actuator 1 requiring the steering assisting force is operated. That is, in the control valve 2 of the actuator 1, the normally closed valve 2a is arranged on the upstream side and the normally open valve 2b is arranged on the downstream side. The control valve 2 is a controller (not shown), a torsion bar mechanism, or the like. The power cylinder 3 is selectively driven and the actuator 1 operates by being selectively opened / closed by the power cylinder 3. As a result, the hydraulic fluid guided to the actuator 1 is consumed in order to appropriately exert the steering assisting force.

When the hydraulic fluid is being discharged from the hydraulic pump 7, the steering assist force becomes unnecessary, and when the actuator 1 shifts from the operating state to the non-operating state, the amount of hydraulic fluid consumed by the actuator 1 gradually decreases. Eventually it becomes zero. Therefore, the hydraulic oil discharged from the hydraulic pump 7 is supplied to the accumulator 33 and accumulated in the accumulator 33. Therefore, the accumulator 33 is provided in the check valve 3 when the actuator 1 is not operating.
The pressure in the hydraulic passage 31 on the downstream side of 2 is maintained at a predetermined pressure.

When the pressure in the hydraulic passage 31 on the downstream side of the check valve 32 held by the accumulator 33 reaches a predetermined pressure, the pressure in the hydraulic passage 31 is guided through the detection oil passage 48. The switch 47 operates to open the power supply circuit 50 to cut off the supply of the exciting current to the electromagnetic coil 38. As a result, the electromagnetic coil 38
Stops the adsorption of the armature 37, and the electromagnetic clutch 34
Is disconnected. As a result, the rotation of the pulley 4 as the driving means continues, but the rotational driving of the hydraulic pump 7 is stopped.

When the hydraulic pump 7 is not rotationally driven, hydraulic oil is not supplied from the hydraulic pump 7 to the hydraulic passage 31, but the hydraulic passage 31 on the downstream side of the check valve 32 is upstream by the check valve 32. The communication with the side is cut off, and a pressure is applied by the accumulator 33 to maintain a predetermined pressure. As a result, during sudden steering or the like, the hydraulic oil accumulated in the hydraulic passage 31 and the accumulator 33 on the downstream side of the check valve 32 is quickly supplied to the actuator 1,
Smooth steering assist operation is achieved.

When the energy accumulated in the accumulator 33 is consumed by the operation of the actuator 1 and the pressure in the hydraulic passage 31 on the downstream side of the check valve 32 falls below a predetermined value, the pressure in the hydraulic passage 31 is reduced. The pressure switch 47 for detection is activated, and the electromagnetic clutch 3 is activated again.
4 is connected. As a result, the hydraulic pump 7 is rotationally driven.

Therefore, in the power steering apparatus of this embodiment, the electromagnetic clutch 34 is brought into contact with or separated from the hydraulic passage 31 according to the pressure in the hydraulic passage 31, and the drive / stop of the hydraulic pump 7 is controlled, that is, the hydraulic pressure is changed. Since the pressure switch 47 connects the electromagnetic clutch 34 to drive the hydraulic pump 7 due to the pressure decrease in the passage 31, the hydraulic pump 7 does not always rotate, and energy can be saved. In addition, by accumulating the working hydraulic pressure in the accumulator 33 in advance, during sudden steering, etc.,
It is possible to solve the problem that the discharge capacity is insufficient due to the rising characteristic of the hydraulic pump 7 when the hydraulic pump 7 is started.

The electromagnetic clutch 34 is brought into contact with and separated from the hydraulic passage 31 according to the pressure in the hydraulic passage 31 to control the driving / stopping of the hydraulic pump 7, thereby controlling the driving of the hydraulic pump 7 without using an electric motor. Since the power consumption of the electromagnetic clutch 34 is smaller than the power consumption of the electric motor, a power steering device with less energy loss and consumption can be obtained.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment and can be changed without departing from the gist of the invention.
For example, the hydraulic pump 7 is not limited to the vane pump,
Various pumps can be adopted. Further, although the configuration in which the pressure switch 47 directly controls the energization of the electromagnetic coil 38 has been described, a relay controlled by the pressure switch 47 is interposed in the power supply circuit 50, and the relay energizes the electromagnetic coil 38. It may be configured to control.

[0041]

As described above in detail, according to the present invention, the hydraulic pump does not always rotate and energy can be saved. Further, by preliminarily accumulating the operating hydraulic pressure in the accumulator, it is possible to eliminate the problem that the discharge capacity becomes insufficient due to the rising characteristics of the hydraulic pump at the time of starting, such as during sudden steering.

Further, since the clutch means is brought into contact with and separated from the hydraulic passage by the pressure in the hydraulic passage to control the drive / stop of the hydraulic pump, the drive of the hydraulic pump can be controlled without using an electric motor, resulting in energy loss and consumption. It is possible to obtain a power steering device with less power consumption.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a power steering device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Actuator 4 Pulley (Driving Means) 6 Internal Combustion Engine 7 Hydraulic Pump 31 Hydraulic Passage 32 Check Valve 33 Accumulator 34 Electromagnetic Clutch (Clutch Means) 47 Pressure Switch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshinori Aihara 1370 Onna, Atsugi-shi, Kanagawa Prefecture

Claims (2)

[Claims] 1. A power steering device for supplying and discharging hydraulic oil to and from an actuator to obtain a steering assisting force in accordance with a steering torque of a steering shaft, and driving means connected to an internal combustion engine and rotationally driven by the driving means. Hydraulic pump,
A hydraulic passage for guiding the discharge oil of the hydraulic pump to the actuator through a check valve, an accumulator provided in a hydraulic passage downstream of the check valve, and a drive passage between the drive means and the hydraulic pump. A power steering device, comprising: clutch means for controlling contact / separation in accordance with a pressure in a hydraulic passage downstream of the check valve to control driving / stopping of the hydraulic pump. 2. The power steering device according to claim 1, wherein the clutch means is an electromagnetic clutch that is controlled to be brought into contact with or separated from the clutch by a pressure switch that operates according to a pressure in a hydraulic passage downstream of the check valve.