JPH04262082A - Fluid pump - Google Patents

Abstract

PURPOSE:To provide a fluid pump capable of changing the discharge flow without making a device large-scaled and complex. CONSTITUTION:Gaps 37, 39 are formed on at least one of both sides in the axial direction of a rotor 15, an electric viscous fluid 41 changed with viscosity by the magnitude of the electric field is filled in the gaps 37, 39, the magnitude of the electric field is properly changed to adjust the viscosity of the electric viscous fluid 41, and the leak quantity of the pressure fluid 41 is adjusted to control the discharge flow.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a fluid pump suitable for use as a pressure source for a power steering device.
In particular, electrorheological fluids (Electro-Rheolog)
The present invention relates to a system in which the discharge flow rate can be controlled without requiring a large and complicated structure by using ical-fluid (hereinafter referred to as ER fluid).

0002

2. Description of the Related Art A power steering system provides power assist to the steering force when the vehicle is traveling at low speeds, but at high speeds it is normal to switch to manual steering in order to stabilize the maneuverability. By the way, a conventional fluid pump used as a pressure source for a power steering device has a configuration as shown in FIG. 3, for example. First, a body 101 and a cover 103 are arranged, and a cam ring 105 is sandwiched between the body 101 and the cover 103. A ball bearing 107 and a metal bearing 109 are provided on the inner circumferential side of the body 101.
However, the interior is arranged along the same axis.

0003

[Prior Art] The ball bearing 109 is connected to the first shaft 11.
1 is rotatably supported. The right end portion of the first shaft 111 in the drawing is arranged to protrude from the body 101 and is linked to an engine (not shown). In addition, the first axis 111
A flange portion 113 is formed at the left end in the figure, and an inclined pawl 115 is formed on this flange portion 113.

A second shaft 117 is rotatably supported by the metal bearing 109 . This second axis 117
A flange portion 119 is formed at the right end in the figure, and an inclined pawl 121 is formed on this flange portion 119. This inclined pawl 121 meshes with the already mentioned inclined pawl 115, and these two inclined pawls 115 and 121 constitute a clutch.

The end of the second shaft 117 opposite to the flange portion 119 is rotatably supported by a metal bearing 123 built into the cover 103 . Further, a rotor 125 is installed inside the cam ring 105. The second shaft 117 passes through this rotor 125,
They are connected via a spline 127. In this way, the second shaft 117 is movable in the axial direction and is configured to rotate together with the rotor 125.

The rotor 125 has a large number of vanes 129.
is installed so that it can appear and retract in the radial direction. When the rotor 125 rotates together with the second shaft 117, the numerous vanes 129 move in and out along the inner peripheral surface of the cam ring 105. The low-pressure fluid sucked in from the suction channel 131 during the rotation process of the rotor 125 is sucked into each chamber partitioned by the large number of vanes 129 . The sucked fluid is compressed and discharged from the discharge passage 133, and the discharged fluid is supplied to a power steering device (not shown).

Insertion holes 135 and 137 are formed in the opposing portions of the first shaft 111 and the second shaft 117, respectively.
A compression coil spring 139 is installed inside these insertion holes 135 and 137. This compression coil spring 139 applies a spring force in a direction that separates the first shaft 111 and the second shaft 117 from each other. A ball 140 is housed in one of the insertion holes 135 . This means that when the first shaft 111 and the second shaft 117 rotate relative to each other,
Allowing free rotation of the compression coil spring 139,
This is to prevent the compression coil spring 139 from being twisted.

At the opposite end of the flange portion 119 of the second shaft 117 is a solenoid 141 that is an electromagnetic actuator.
A push rod 143 is arranged in contact with the push rod 143 . A spring receiver 145 is located midway in the axial direction of the push rod 143.
is provided, and this spring receiver 145 and the guide member 1
A compression coil spring 149 is connected between the proximal end of the
is installed. The spring force of this compression coil spring 149 is set larger than that of the compression coil spring 139 already described. In addition, the solenoid 14
1 is connected to a controller 151, which receives signals from a vehicle speed sensor 153 and a steering angle sensor 155, and controls energization/de-energization of the solenoid 141 based on the signals.

In the above configuration, when the first shaft 111 and the second shaft 117 rotate together in accordance with the rotation of the engine, the second shaft 111 and the second shaft 117 rotate together.
A rotor 125 integrally fixed to the shaft 117 also rotates. As a result, pressure fluid flows out from the discharge passage 133 and is supplied to the power steering device. As a result, power assist power is demonstrated.

On the other hand, when the vehicle is running at high speed, current is supplied to the solenoid 141 by the action of the controller 151. Due to the magnetic force generated thereby, the push rod 143 is attracted to the left side in the figure against the spring force of the compression coil spring 149. When the push rod 143 moves and its end part separates from the second shaft 117, the second shaft 117 is biased to the left in the figure by the compression coil spring 139. As a result, the second shaft 117 is separated from the first shaft 111, and the rotation on the first shaft 111 side is no longer transmitted to the second shaft 117 side. As a result, the rotation of the rotor 125 also stops, so the fluid pump stops and fluid is no longer discharged. Further, when the discharge flow rate becomes O, the assist force to the power steering device is also lost, and manual steering is performed.

When the vehicle speed is reduced from the above-mentioned high-speed running state, the solenoid 141 becomes de-energized again by the action of the controller 151. Therefore, the push rod 143 is moved to the right in the figure by the spring force of the compression coil spring 149, and thereby the second shaft 1
17 moves to the right in the figure against the spring force of the compression coil spring 139. Then, the second shaft 117
The shaft 111 is connected to the shaft 111 . Therefore, the rotation on the first shaft 111 side is transmitted to the second shaft 117 side, the rotor 125 rotates, and the power assist state described above is achieved.

0012

[Problems to be Solved by the Invention] The above conventional configuration has the following problems. That is, there is a problem that the structure for controlling the connection/decoupling of the first shaft 111 and the second shaft 117 is complicated and large. That is, in order to move the second shaft 117 in the axial direction, a structure centered around the solenoid 141 is required.

The present invention has been made based on the above points, and an object of the present invention is to provide a fluid pump that makes it possible to vary the discharge flow rate without increasing the size or complication of the device. Our goal is to provide the following.

[0014]

[Means for Solving the Problems] In order to achieve the above object, a fluid pump according to the present invention transmits the rotational force of an input shaft linked to a drive source such as an engine to a rotor, and transmits pressure fluid according to the rotation of the rotor. In a fluid pump that discharges
A gap is formed in at least one of both sides in the axial direction of the rotor, and this gap is filled with an electrorheological fluid whose viscosity changes depending on the magnitude of the electric field.By appropriately changing the magnitude of the electric field, the viscosity of the electrorheological fluid is This feature is characterized in that the discharge flow rate is controlled by adjusting the leakage amount of the pressure fluid.

[0015]

[Operation] For example, when increasing the discharge flow rate of pressure fluid, the magnitude of the electric field is increased. This increases the viscosity of the electrorheological fluid filling the gap and reduces the amount of pressure fluid leaking through the gap. This increases the discharge flow rate of the pressure fluid. On the contrary,
When reducing the discharge flow rate of the pressure fluid, the magnitude of the electric field is reduced. This lowers the viscosity of the electrorheological fluid filling the gap and increases the amount of pressure fluid leaking through the gap. Thereby, the discharge flow rate of the pressure fluid is reduced.

[0016]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a fluid pump according to this embodiment, and FIG. 2 is an exploded perspective view. A cover 3 is fixed to the body 1 by a plurality of fixing bolts 2 (four in this embodiment, as shown in FIG. 2). A seal ring 4 is inserted between the body 1 and the cover 3. As shown in FIG. 1, a metal bearing 7 is installed inside the body 1 via an insulating tube 5 (not shown in FIG. 2). Further, a metal bearing 11 is housed inside the cover 3 via an insulating tube 9 (not shown in FIG. 2). An input shaft 13 is rotatably supported by the metal bearings 9 and 11.

The right end of the input shaft 13 in the figure is connected to an engine (not shown), and a rotor 15 is fixed to the input shaft 13 via a spline 14. A large number of vanes 17 are attached to the outer periphery of the rotor 15 so as to be retractable in the radial direction. These vanes 17 are molded from an insulating material. Further, a cam ring 19 is installed inside the outer circumferential side of the vane 17 and the inner circumferential side of the body 1. Then, due to the rotation of the input shaft 13, the rotor 1
5 rotates, a large number of vanes 17 rotate while appearing and retracting along the cam surface of the cam ring 19. The low-pressure fluid sucked in from the suction channel 21 during the rotation process of the rotor 15 is sucked into each chamber partitioned by the large number of vanes 17 . The sucked fluid is compressed and discharged from the discharge passage 23, and the discharged fluid is supplied to a power steering device (not shown).

A side plate 25 is arranged on the right side of the rotor 15 in the drawing. This side plate 25
The cam ring 19 is in contact with the cam ring 19, and seal rings 22 and 24 are inserted between the side plate 25 and the body 1, as shown in FIG. or,
A communication hole 27 is formed in the outer periphery of the side plate 25, and the right side of the communication hole 27 in the figure is connected to the loading chamber 2.
9, and high pressure fluid is introduced into the loading chamber 29. Further, a passage 31 is formed in the inner peripheral portion of the side plate 25, and this passage 31 is communicated with the high pressure chamber 35 via an annular passage 33. In other words, the loading chamber 29 is communicated with the high pressure chamber 35.

A gap 37 is provided on both sides of the rotor 15 in the axial direction.
39 are formed respectively. Normally, the gap on both sides of the rotor 15 in the axial direction is controlled to about 0.02 mm.
In the case of this embodiment, this is enlarged to, for example, about 1 mm, and the gaps 37 and 39 are actively formed. Both gaps 37 and 39 are filled with ER fluid 41. This ER fluid 41 is a fluid that has the property of changing its viscosity depending on the magnitude of the electric field. Specifically, as the electric field increases, its viscosity increases, and in extreme cases, it becomes similar to a solid. become a state. On the other hand, by decreasing the electric field, the viscosity decreases. Regarding such ER fluid, for example,
This is described in Publication No. 0-4630, etc.

The configuration for controlling the electric field applied to the viscous fluid 41 is as follows. An electric circuit 43 is provided between the body 1 and the input shaft 13. A switch 45 and a power source 47 are inserted into this electric circuit 43. The controller 49 controls the opening and closing of the switch 45.
controlled by The controller 49 opens and closes the switch 45 based on signals from the vehicle speed sensor 51 and the steering angle sensor 53.

When the switch 45 is closed, a voltage is applied between the side surface of the rotor 15 functioning as an electrode surface and the side surfaces of the cover 3 and the side plate 25, thereby creating a large electric field in the electrorheological fluid 41. is applied,
The viscosity of the electrorheological fluid 41 increases. Thereby,
Leakage of the pressure fluid from the high pressure side to the low pressure side is regulated, thereby increasing the discharge flow rate of the pressure fluid and thus the flow rate of the pressure fluid supplied to the power steering device, and the desired power assist force is exerted. On the other hand, when the switch 45 is opened, the electric field is no longer applied to the electrorheological fluid 41, so its viscosity becomes low, and the amount of pressure fluid leaking from the high pressure side to the low pressure side increases. Therefore, the discharge flow rate of the pressure fluid and the flow rate of the pressure fluid supplied to the power steering device decrease (or
(becomes zero), and the power assist force stops exerting itself.

Note that a seal member 55 is inserted between the input shaft 13 and the body 1. As shown in FIG. 2, the body 1 is provided with a pressure switch mechanism 57, and the discharge flow path 23 is provided with a flow control mechanism 59. Also, in FIGS. 1 and 2, reference numeral 61 is an O-ring, and reference numeral 63 is an O-ring.
is a fixing bolt. Further, reference numeral 65 is a retaining ring that restricts movement of the input shaft 13 in the axial direction.

The operation will be explained based on the above configuration. First, during normal driving, including low-speed driving, the controller 4
9 closes the switch 45. By closing this switch 45, a current flows through the electric circuit 43, and E
A voltage is applied to the R fluid 41. As a result, the viscosity of the ER fluid 41 becomes high, and the ER fluid 41 becomes in a state similar to that of a solid. Therefore, the amount of pressure fluid leaking from the high pressure side to the low pressure side in the rotor 15 is regulated, and the discharge flow rate of the pressure fluid and thus the flow rate of the pressure fluid supplied to the power steering device is increased. Thereby, the desired power assist force is exerted.

Next, high speed running will be explained. First, the switch 45 is opened by the action of the controller 49. By opening the switch 45, the ER fluid 41
The application of voltage to is stopped, and the viscosity of the ER fluid 41 becomes low. Therefore, the amount of leakage of pressure fluid from the high pressure side to the low pressure side of the rotor 15 increases, and the discharge flow rate of the pressure fluid and thus the flow rate of the pressure fluid supplied to the power steering device decreases (or becomes zero). As a result, the power assist force is stopped and manual steering becomes available.

Further, when the vehicle speed decreases from the above-mentioned high-speed running state, the switch 45 is closed by the controller 49, and the state returns to the state where the power assist force is exerted.

According to this embodiment, the following effects can be achieved. First, the discharge flow rate of the fluid pump can be controlled without requiring a large and complicated structure as in the past. Specifically, conventionally, a configuration for moving the second shaft 117 (shown in FIG. 3) was required;
In the case of this embodiment, such a configuration is not necessary at all,
This is because it is sufficient to simply fill the gaps 37 and 39 with the ER fluid 41.

Furthermore, in the case of the ER fluid 41, it responds instantaneously to the application/stopping of voltage and changes its viscosity, and as a result, the discharge flow rate of the fluid pump is controlled with high responsiveness. be able to.

It should be noted that the present invention is not limited to the above embodiment. In the above embodiment, the controller 49 opens and closes the switch 45 to change the viscosity of the ER fluid 41 on and off, but the applied voltage can be continuously controlled to finely and continuously adjust the discharge flow rate. It may also be controlled. Further, in the above embodiment, the gaps 37 and 39 are formed on both sides of the rotor 15 in the axial direction, but they may be formed on either one side.

[0029]

As described in detail above, according to the fluid pump of the present invention, a gap is formed on at least one of both sides of the rotor in the axial direction, and an electrorheological fluid whose viscosity changes depending on the magnitude of the electric field is filled in this gap. The viscosity of the electrorheological fluid is adjusted by filling the fluid and changing the magnitude of the electric field appropriately, and the discharge flow rate is controlled by adjusting the leakage amount of the pressure fluid. Moreover, the discharge flow rate can be controlled without requiring a complicated structure. Moreover, its responsiveness is also high.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fluid pump showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of a fluid pump showing one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional fluid pump.

[Explanation of symbols]

13 Input shaft 15 Rotor 37 Gap 39 Gap 41 ER fluid (electrorheological fluid)

Claims (1)

[Claims] Claim 1. A fluid pump that transmits the rotational force of an input shaft linked to a drive source such as an engine to a rotor and discharges pressure fluid in accordance with the rotation of the rotor, wherein a fluid pump is provided on at least one of both sides of the rotor in the axial direction. A gap is formed, this gap is filled with an electrorheological fluid whose viscosity changes depending on the magnitude of the electric field, and the viscosity of the electrorheological fluid is adjusted by appropriately changing the magnitude of the electric field. A fluid pump characterized in that the discharge flow rate is controlled by adjusting the amount of leakage.