JP3044241B2 - Hydraulic pump and power steering device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump mounted on a vehicle and a power steering apparatus using the hydraulic pump as a source of operating hydraulic pressure.

[0002]

2. Description of the Related Art In recent automobiles, power steering devices (power steering devices) have become widespread in order to reduce the labor required for operating steering wheels (steering wheels) for steering and to obtain a comfortable steering feeling. ing.

[0003] The power steering device is roughly classified into a hydraulic type using a hydraulic actuator as a source of a steering assist force and an electric type using an electric motor. Supplies the hydraulic pressure generated by the hydraulic pump mounted on the vehicle to the hydraulic actuator in accordance with the steering operation, and applies the hydraulic pressure generated by the hydraulic actuator to the steering mechanism by the supplied hydraulic pressure, and operates in the steering direction of the steering wheel. The steering assist force according to the amount is obtained.

The hydraulic pump is often driven by an engine mounted on a vehicle. Generally, the hydraulic pump is disposed between a V-pulley fitted to a shaft end of a rotor shaft of the hydraulic pump and an output end of the engine. A configuration is employed in which a V-belt is wound and a rotor is driven to rotate by a part of the torque of the engine transmitted through the V-belt.

[0005]

The steering of an automobile is performed against a road surface reaction force acting on a steered wheel. The magnitude of the road surface reaction force is determined by the slowness of the traveling speed and the magnitude of the steering angle. Accordingly, the power steering apparatus is required to generate the maximum steering assist force in a state where the steering is largely performed at the time of low-speed traveling or stop, that is, a so-called stationary state. Therefore, the specifications of the hydraulic pump that generates the operating oil pressure of the power steering device are determined on the basis of securing the required oil pressure and the required oil amount in the stationary state, that is, under a high load, and the vehicle speed is high. In addition, at the time of high-speed running in which a large steering operation is not performed, that is, at the time of low load, the excess oil discharged by the hydraulic pump is returned to the oil tank without being supplied to the hydraulic actuator. I have.

However, when the hydraulic pump whose specifications are determined as described above is driven by an engine, the rotational speed of the engine is generally high during high-speed running. As a result, a large amount of surplus oil that is not supplied to the hydraulic actuator is generated, and an unnecessary load of power for pressurizing the surplus oil causes an increase in the load on the engine and a decrease in fuel efficiency due to the increase in the engine load. There was a drawback to invite.

[0007] CAFE recently implemented in the United States
Fuel efficiency regulations for automobiles, such as fuel efficiency regulations based on (Corporate Average Fuel Economy) values, tend to be further strengthened. In order to cope with such fuel efficiency regulations, the operating oil pressure of the power steering device must be generated. The elimination of unnecessary power consumption as described above in a hydraulic pump to be used is an important issue.

In order to solve such difficulties, for example, in Japanese Patent Application Laid-Open No. 57-70772, the hydraulic pump is an electric pump driven by a motor, and the energization of the motor is performed by detecting the vehicle speed. Controlling according to the result, the hydraulic pump is driven at a low speed when traveling at high speed, and at a high speed when traveling at low speed and stopped, respectively, to generate the required hydraulic pressure and required oil amount during stationary installation, There has been proposed a power steering device designed to reduce surplus oil during high-speed running.

However, in this configuration, the motor selected under the condition that it can bear the maximum driving force of the hydraulic pump under a high load becomes large, and it is difficult to secure the arrangement position of the motor. There are disadvantages associated with.

The present invention has been made in view of the above circumstances, and has been made to secure the required hydraulic pressure and required oil amount under a high load and to reduce the excess oil under a low load by increasing the size of a drive motor and increasing the engine speed. The present invention provides a hydraulic pump that can be realized without increasing the load on the engine, and by using this hydraulic pump, it is possible to reduce fuel consumption deterioration in the engine as much as possible and to cope with the recently tightened fuel efficiency regulations. It is an object to provide a steering device.

[0011]

SUMMARY OF THE INVENTION A hydraulic pump according to the present invention is a hydraulic pump that generates a hydraulic pressure by being rotationally driven by an electric motor mounted on a vehicle, wherein a rotating shaft of the electric motor is connected to an engine for driving the vehicle. The power steering apparatus according to the present invention, comprising a clutch for connecting to the output end, uses the hydraulic pump, and disengages the clutch in accordance with a slow traveling speed of the vehicle. Means, and means for interrupting energization of the electric motor when the clutch is engaged.

[0012]

In the present invention, the electric motor and the engine are selectively used as drive sources for the hydraulic pump by engaging and disengaging the clutch, and the clutch is engaged during stationary operation, that is, at a high load, so that the engine is used as the drive source. While preventing the electric motor from increasing in size, the clutch is disengaged when the load is low, and the electric motor is selected as a drive source, thereby preventing unnecessary power consumption by a high-speed rotating engine and improving fuel efficiency.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a partially broken longitudinal sectional view of a hydraulic pump according to the present invention. As shown in the drawing, the hydraulic pump according to the present invention has a configuration in which a motor 2 and an electromagnetic clutch 3 are coaxially connected to one side of a pump body 1.

The pump body 1 includes a cylindrical rotor 10 having a plurality of vanes (not shown) which are movable in the radial direction.
Are housed coaxially inside a cam ring 13 forming an unbalanced annular shape which is sandwiched and fixed between a pair of side plates 11 and 12, and these are integrally housed in a housing 14. Oil introduced through a suction hole 15 penetrating the peripheral wall of the housing 14 is supplied to the outer periphery of the rotor 10 and the cam ring.
13 into the pump chamber formed between
The pressure is increased by the rotation of 10, and the pressure is increased and discharged to the side plate 11 side, and is supplied to a power steering device (not shown) through a discharge hole 16 which also penetrates the peripheral wall of the housing 14.

The motor 2 has a thin cylindrical yoke housing 21 having a magnet 20 provided around the inner surface thereof, and one end of the yoke housing 21 coaxially fixed to the outer surface of the housing 14 of the pump body 1 coaxially. Inside the yoke housing 21, a coil 23 fixedly mounted on the outer periphery of a middle part of the rotating shaft 22 is coaxially housed. At the other end of the yoke housing 21, a thick-walled hollow disc-shaped grommet 24 is coaxially flanged.

The rotating shaft 22 of the motor 2 is extended inside the housing 14 of the pump body 1 and outside the grommet 24, and the extending part toward the housing 14 is fitted to the housing 14. A ball bearing 17 supports the extended portion to the grommet 24 side as described later, and an extended end of the rotating shaft 22 to the housing 14 is connected to one side of the cam ring 13. Through the side plate 12 of the rotor 10
It is attached to.

Electric power is supplied to the coil 23 of the motor 2 through a power supply line 25 extending from the outer peripheral edge of the grommet 24 to the inside and a brush (not shown) formed on the inner peripheral side of the grommet 24. The rotation of the rotating shaft 22 generated by the energization in the magnetic field inside the housing 21 drives the rotor 10 of the pump body 1 to rotate.
, The pump action as described above is performed.

The electromagnetic clutch 3 is provided around the outer surface of the grommet 24 coaxially therewith, and has an annular yoke 31 having a built-in excitation coil 30 to form a magnetic circuit;
A support plate 32 fitted coaxially and relatively rotatably on the extended end of the rotating shaft 22 to the outside of the shaft, and constrains rotation on the outer peripheral side of the support plate 32 and is freely movable in the axial direction. Armature 33 attached to the armature 33, and a thick disk-shaped slider interposed between the armature 33 and the yoke 31 with a slight gap therebetween and spline-coupled to the rotating shaft 22. The structure includes a moving plate 34. The ball bearing 18 on the grommet 24 side is fitted on the inner periphery of the yoke 31, and supports the rotating shaft 22 via a sliding plate.

The energizing of the exciting coil 30 of the electromagnetic clutch 3 is performed from the outer peripheral side of the yoke 31 via a power supply line 35. When the energizing is performed, the armature 33 is actuated by the action of the magnetic circuit generated in the yoke 31. Attracted to the sliding plate 34,
The friction members fixed on the opposing surfaces of the two slide against each other,
Due to this frictional resistance, the support plate 32 and the rotating shaft 22 are engaged via the armature 33 and the sliding plate.

A V-pulley 4 is integrally fixed to the end of the rotating shaft 22 of the support plate 32. The V-pulley 4 is connected to a V-belt wound around the V-pulley 4 for an engine (not shown). Connected to the output shaft. That is, the support plate 32 is constantly rotating by the driving force of the engine transmitted to the V pulley 4,
When the electromagnetic clutch 3 is engaged by energizing the excitation coil 30, the rotating shaft 22 rotates by the rotation of the support plate 32, and the rotor 10 of the pump body 1 is driven to rotate by the output of the engine. The above-described pump action in the pump body 1 is performed accordingly.

A power supply line 25 to the motor 2 is connected to the drive circuit 5, and a power supply line 35 to the electromagnetic clutch 3 is connected to the excitation circuit 6.
Correspond to the respective power supply lines 2 in response to an operation command from the control unit 7.
Energize 5, 35. The detection result of the vehicle speed sensor 8 for detecting the traveling speed of the vehicle is given to the input side of the control unit 7, and the control unit 7 outputs the detection result of the vehicle speed sensor 8 to a predetermined reference speed set in advance. Drive circuit 5 when exceeded
, An operation command is issued only to the excitation circuit 6 when the detection result of the vehicle speed sensor 8 falls below the reference speed.

That is, in this case, when the current vehicle speed detected by the vehicle speed sensor 8 is high, that is, during high-speed running, the electromagnetic clutch 3 is cut off by energizing the exciting coil 30 and the coil 23 is energized. Is performed, the motor 2 rotates, and the rotor 10 of the pump body 1 is driven to rotate by the generated force of the motor 2. On the other hand, when the current vehicle speed detected by the vehicle speed sensor 8 is low, that is, when the vehicle is running at a low speed or stopped, the motor 2 is stopped by energizing the coil 23 and the electromagnetic clutch 3 is energized by energizing the exciting coil 30. When engaged, the rotor 10 of the pump body 1 is driven to rotate by the output of the engine transmitted through the V pulley 4.

As described above, the steering assist force required for the power steering device operated by the oil supply from the pump body 1 is small during high-speed running, and large during stop and low-speed running. Therefore, during high-speed running in which the rotation of the rotor 10 is performed by the force generated by the motor 2, the amount of oil fed from the pump body 1 to the power steering device via the discharge hole 16 may be small, and Also do not need. For this reason, a small-capacity motor 2 is sufficient. On the other hand, during low-speed running and when the rotor 10 is rotationally driven by the engine, a sufficiently high output of the engine ensures a high oil pressure and a large amount of oil to be supplied from the pump body 1. The power steering device that operates by refueling can generate the required steering assist force with a margin. In addition, since the power burden by the engine is performed only when the vehicle is running at low speed and when the vehicle is stopped, there is no possibility that the power burden causes a decrease in the fuel efficiency of the engine.

The order of arranging the pump body 1, the motor 2 and the electromagnetic clutch 3 is not limited to the order shown in the present embodiment. Instead of the electromagnetic clutch 3, a hydraulic clutch, etc. Other clutches may be used.

[0025]

As described above in detail, in the hydraulic pump according to the present invention, one end of the rotating shaft of the driving motor is connected to the output end of the engine via a clutch, and the motor is driven by disengaging the clutch. And, since the engine can be selectively used as a drive source, an engine having a sufficient output by engaging a clutch at a high load is selected as a drive source,
When the load is low, the clutch is disengaged and the motor is selected as a drive source, so that the size of the motor can be reduced, and unnecessary power burden on the engine can be prevented. Further, in the power steering apparatus according to the present invention using the hydraulic pump, the clutch is disengaged in accordance with a slow traveling speed of the vehicle, and the electric motor is energized when the clutch is engaged. Since the shutoff is performed, a sufficient steering assist force at the time of stationary operation can be obtained without causing a decrease in the fuel efficiency of the engine, and the present invention has an excellent effect, for example, it can cope with the stricter fuel efficiency regulations in recent years.

[Brief description of the drawings]

FIG. 1 is a partially broken longitudinal sectional view of a hydraulic pump according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump main body 2 Motor 3 Electromagnetic clutch 4 V pulley 5 Drive circuit 6 Excitation circuit 7 Control part 8 Vehicle speed sensor 10 Rotor 13 Cam ring 14 Housing 20 Magnet 21 Yoke housing 22 Rotating shaft 30 Excitation coil 31 Yoke 33 Armature

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model 4-106082 (JP, U) Japanese Utility Model Sho 58-15882 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B62D 6/02

Claims (2)

(57) [Claims] 1. A hydraulic pump which generates a hydraulic pressure by being rotationally driven by an electric motor mounted on a vehicle, comprising a clutch for connecting a rotating shaft of the electric motor to an output end of a driving engine of the vehicle. A hydraulic pump characterized by the following. 2. A power steering device using the hydraulic pump according to claim 1 as a source of operating hydraulic pressure, wherein the clutch is disengaged in accordance with a low traveling speed of the vehicle. Means for interrupting energization of the electric motor when the clutch is engaged.