JPS5828464Y2 - Electrical ↓-mechanical converter using solenoid coil - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electro-mechanical converter using a solenoid coil. The present invention relates to an electro-mechanical converter that proportionally moves a plunger in an axial direction.

This type of electro-mechanical converter is known, for example, from Japanese Unexamined Patent Publication No. 49-1
As shown in Publication No. 08732, the opening degree of a needle control valve connected to the plunger is adjusted in conjunction with the movement of the plunger in the axial direction, which is generated by supplying a control signal according to the vehicle speed of the vehicle to the solenoid coil. This is used to control the flow rate of fluid supplied to power steering.

However, in the structure of a conventional electromechanical converter, the plunger is tightly coupled with the magnetic flux generated around the solenoid coil in response to the control signal supplied to the solenoid coil, in other words, the magnetic resistance is minimized. In order to do this, the outer diameter of the plunger made of magnetic material is formed as close as possible to the inner diameter of the cylinder, and furthermore, a part of the cylinder is made of magnetic material and its tip is arranged as close to the end of the plunger as possible. There is.

As a result, the plunger moves while sliding on the inner wall of the cylinder in accordance with the magnetomotive force generated by the solenoid coil in response to the control signal.

Therefore, sliding frictional resistance is generated between the plunger and the cylinder, and when the plunger performs reciprocating motion in cooperation with the above control signal and the spring bias of the return spring, as shown in FIG. It will have hysteresis characteristics.

That is, in FIG. 1, the horizontal axis represents the control signal (current) supplied to the solenoid coil, and the vertical axis represents the amount of displacement of the plunger.

To explain this hysteresis characteristic using the same figure, in the electro-mechanical converter of the conventional structure described above, when the control signal is gradually increased, the current 11 reaches the plunger point P1 to the 22nd point, as shown by characteristic a. It moves a lot, then gradually changes to a current of 12 and moves to a point of 43.

After that, it settles on 43 points regardless of the change in current.

On the other hand, when the control signal is made smaller, the characteristics do not change at currents 11 and 12 as already shown, but at current i3, which is even smaller than current 11, it moves greatly from 43 to 44 points, and after that, It gradually moves up to the current i4 and settles at the original 41 points. Therefore, when using an electro-mechanical transformer with such a displacement-control signal characteristic,
It is difficult to perform linear control due to the sliding friction loss that occurs between the cylinder and the plunger, and the displacement range is small, so its use has been limited to simple on/off operations.

If an electro-mechanical converter with such hysteresis characteristics is used in power steering to control the flow rate, the steering wheel will suddenly become lighter or heavier at the point where the flow rate changes; This differs depending on the direction, and the driver's steering sensation is impaired.

Therefore, the main objective of the present invention is to provide an electro-mechanical converter using a solenoid coil that eliminates hysteresis characteristics.

Another object of the present invention is to provide an electro-mechanical converter using a solenoid coil that can linearly change mechanical displacement over a wide range in response to a control signal.

In order to achieve this purpose, the present invention disposes the plunger in a loosely fitted manner within the cylinder so that the plunger can freely move within the cylinder without causing sliding friction loss. The bearing that supports the guide rod movably is composed of a ball inserted around the guide rod, a ball holder that holds the ball, and a pair of springs that press and support the ball from both sides. This will be explained in detail using an example.

Figure 2 shows an electrical connection using a solenoid coil according to the present invention.
An example of a mechanical transducer is shown, particularly when applied to a power steering flow control device.

In the figure, a flow control device 10 includes a servo valve 12 including an electric converter using a solenoid, and a servo valve 12 that includes an electric converter using a solenoid.
and a flow rate controller 15 that controls the flow rate supplied to the power steering 14.

First, the servo valve 12 will be described. The servo valve 12 has a cylindrical plunger 16, a cylindrical cylinder 17 housing the plunger, and a solenoid coil 19 disposed around the cylinder 17 via a coil bobbin 18.

The plunger 16 has an outer diameter slightly smaller than the inner diameter of the cylinder 17 so as to prevent sliding friction loss from occurring between the plunger 16 and the cylinder 17, and guide rods 21 and 22 extending axially from both ends thereof. Further, a needle control valve body 23, which constitutes a needle control valve together with an orifice to be described later, extends in the axial direction from the tip of one guide rod 22.

The plunger 16, which is loosely fitted within the cylinder 17, is movably supported within the cylinder 17 by bearings 25 and 26 which are movably inserted into guide rods 21 and 22 on both sides of the plunger 16, respectively. ing.

These bearings 25 and 26 are the parts that characterize the present invention.
As shown in FIG. 3, each ball holder 27 has a substantially cylindrical shape, and the inner diameter of the holder 27 is larger than the outer diameter of the guide rods 21 and 22, while the outer diameter is smaller than the inner diameter of the cylinder 17. set and also this holder 27
has a plurality of through holes 29 equally spaced in the centripetal direction on its surface.

Each through hole 2 of the holder 27 with such a structure
A ball 3L32 is rotatably inserted into the ball 9.

Each of these balls 31 and 32 has an outer diameter such that a part thereof contacts the circumferential surface of the guide rods 21 and 22, and the opposite side contacts the inner wall of the cylinder 17.

Further, the holders 27 constituting the bearings 25 and 26 are each formed with flanges 33 and 34 (FIG. 3) at their axial ends, and a pair of springs 3B, 39; 40, It is adapted to receive one end of 41.

In this case, the spring 39 is attached to the holder 2 of one of the bearings 25.
7 and the plunger 16, the spring 40
is arranged between the plunger 16 and the holder 27 of the other bearing 26.

The other end of the spring 38 is supported by a spring receiver 45 that is inserted into the cylinder 17 via an O-ring 43 and fixed to the end of the cylinder 17 by a presser ring 44.

Here, the cylinder 17 is a cylindrical portion 17 made of a magnetic material.
a, a cylindrical portion 17b made of a non-magnetic material disposed between them, and a recess 51 of the servo valve base 50 following this, and one end is in contact with the holder 27 of the other bearing 26. The other end of the spring 41 is locked to the bottom of the recess 51.

Further, a needle control valve body 23 that interlocks with the plunger 16 described above is movably inserted through a hole 52 penetrating the bottom of the recess 51 in the axial direction.

The needle control valve body 23, together with the needle control valve body 23, forms an orifice 5 that constitutes a two-door control valve.
It is facing 3.

Furthermore, through holes 54 and 55 are provided in the servo valve base 50 in a direction communicating with and orthogonal to the through hole 52.

In the figure, 57 is a yoke, 58 is a cover, and 59 is an input terminal of the solenoid coil 19.

Further, the flow rate controller 15 to which the above-described servo valve 12 is attached has an inlet 60 communicating with the through hole 54, and a chamber 61 communicating with the orifice 53. Through hole 55
These chambers 6L6 communicate with each other via a passage 62.
2 and a discharge port 6 that communicates with the chamber 63.
5.

The chamber 63 houses a plunger 66 that is movable within the chamber 63 and a spring 67 that biases the plunger 66 in one direction and normally prevents communication between the flow path 62 and the discharge port 65. .

Note that 68 is a blind plug.

Further, the inlet 60 of the flow rate controller 15 is connected to an oil reservoir 74 via a conduit 71, a relief valve 72, and a pump 73, and the chamber 61 is connected to the power steering 14 via a conduit 76.

Additionally, the outlet 65 is connected to the oil sump 74 via conduits 78,79.
The power steering 14 is also connected to the conduit 80.79.
It is connected to oil sump 74 via.

In addition, the IJ IJ-F valve 72 is also connected to the oil sump 7 via the conduit 81.
4 has been contacted.

With this configuration, when the vehicle is stopped and no current is supplied to the solenoid coil 19 of the servo valve 12, the plunger 16 is maintained in the state shown in FIG. 2.

When the car starts running, a current corresponding to the speed of the car is supplied to the solenoid coil 19, and a magnetic flux proportional to the current is generated by the solenoid coil 19. 2, the plunger 16 is moved toward the needle control valve, that is, toward the right in FIG.

First, since the needle control valve body 23 is sufficiently separated from the orifice 53 when traveling at low speed, the flow rate controller 1 is
The fluid led to the inlet 60 of the 5 is directly sent to the power steering 14 via the chamber 61 without the flow rate being controlled by the orifice 53, and the function of the power steering 14 is fully demonstrated and the fluid is not controlled in flow rate by the orifice 53. To make steering force light.

Such an operation can be similarly applied to steering while the vehicle is stopped.

Next, when the car is traveling at high speed, the current supplied to the solenoid coil 19 also increases, and accordingly, the amount of rightward movement of the plunger 16 also increases, causing the needle control valve body 23 to enter the orifice 53. This is throttled to control the flow rate of fluid passing through the orifice 53.

Therefore, the fluid supplied from the oil reservoir 74 to the inlet 60 of the flow rate controller 15 via the pump 73 is squeezed by the needle control valve constituted by the needle control valve body 23 and the orifice 53, and the flow rate is restricted. The fluid is supplied to the power steering 14.

Therefore, the power steering 14 increases the steering force and operates to require a large steering force when driving at high speed.

The flow rate controller 15 moves the plunger 66 to the right against the spring force of the spring 67 when the pressure on the inlet 60 side across the orifice 53 becomes higher than the pressure in the chamber 63 by a predetermined value or more. The fluid on the inlet 60 side is returned to the oil reservoir 74 via the through holes 54 and 55, the flow path 62, the chamber 63, and the outlet 65.

When the pressure difference between the input and output sides of the IJ IJ valve 72 reaches a predetermined value or more, the IJ IJ valve 72 also transfers fluid to the oil sump 74.
It has the function of returning to

Now, the operation of the electro-mechanical converter of the servo valve 12 characterized by the present invention will now be described.

That is, in the above structure, when the plunger 16 moves to the right based on the attraction force by the solenoid coil 19, the plunger 16 moves toward the balls 31 and 32.
Since it is movably supported with respect to the cylinder 17 only by bearings 25 and 26 using , there is only rolling friction resistance loss due to balls 31 and 32 between them,
This loss is significantly smaller than conventional sliding friction loss.

To explain this in detail, in this type of servo valve 12, the plunger 16 is always stably supported within the cylinder 17,
In order to configure the plunger 16 to be movable without sliding friction, the plunger 16 is movably supported in the cylinder 17 via the balls 31 and 32, and the balls 31 and 32 are completely moved in accordance with the movement of the plunger 16. What we need to do is to encourage people to relocate.

However, the issues here are the space inside the cylinder 17 that accommodates the plunger 16, ease of assembly, and the magnetic gap between the cylinder 17 and the magnetic pole in order to move the plunger 16 appropriately and reliably. It is a must.

In addition, in order for the balls 31 and 32 to move perfectly, the amount of movement must be half of the distance traveled by the ball contact surface, which requires some ingenuity.

Therefore, the present invention takes these conditions into consideration, and in order to satisfy these conditions, the plunger 16 is loosely fitted into the cylinder 17, and the inner wall of the cylinder 17 is arranged around the guide rods 21 and 22 at both ends of the plunger 16. A plurality of balls 3L32 are interposed between them, and these balls 31
, 32 from both ends thereof, a pair of springs 3B,
39 ; 40. It is held by a ball holder 27 that is supported by pressure at 41.

By doing this, the balls 31, 32
The rolling motion of the balls 31, 32 is perfectly matched with the movement of the ball holder 21 following the movement of the plunger 16.
, that is, the guide rod 21 of the plunger 16.
22 and the inner wall surface of the cylinder 17, each ball 31, 3
2 can perform a complete transfer movement without slipping.

Here, the ball holder 27 is inserted into the spring 3 from both sides.
8, 39; 40, 41 is used to support the balls 30, 31 stably at appropriate positions at all times, and to facilitate transfer.
This is to prevent the balls 30, 31 from moving due to vibration or the like and impairing the rolling motion of the balls 30, 31.

In such a bearing 25, 26, the balls 30,
There is an advantage that the machining accuracy of 31 and the parts in contact therewith can be set loosely.

In addition, when bearings 25 and 26 with such a configuration are used, each member can be easily and properly assembled by simply loosely fitting them, so it has excellent workability and assembly, and can be used even in places with limited space. Since it can be easily incorporated, its practical effects are great.

A pair of springs 38 press and support the ball holder 27 holding the balls 30 and 31 from both sides.
39; 40 and 41, it is easily understood that it is optimal if the spring constants are set equal.

According to the servo valve 12 that employs the above-described configuration, when a control signal (current) is supplied to the solenoid coil 19, the plunger can be moved proportionally according to the magnitude of the control signal (current), and the plunger 16 can be moved in proportion to the magnitude of the control signal (current). It will be clear that the same applies when moving in the opposite direction.

Therefore, if the electro-mechanical converter according to the present invention is used, the plunger 16 will gradually move proportionally between the 21st point and the 13th point as shown in characteristic C in FIG. Has no characteristics.

As a result, the mechanical displacement can be linearly varied over a wide range in response to the control signal.

Also, a ball holder 27 constituting the bearings 25 and 26
a pair of springs 3B, 39 from both sides;
40, 41 and guide rods 21, 22
Because the ball is movable relative to
The amount of movement is half the amount of movement of the plunger 16, and as a result, rolling friction loss can be further reduced.

When the present invention is applied to a power steering flow rate control device as in the embodiment described above, the flow rate switching to the power steering system 14 between low-speed running and high-speed running is performed smoothly. It is possible to prevent the driver's steering feeling from being impaired.

It should be noted that the present invention is not limited to the embodiments described above, and it goes without saying that various applications and modifications can be considered.

For example, in this embodiment, the balls 31 and 32 that movably support the plunger 16 with respect to the cylinder 17 are generally steel balls, but balls made of other materials may be used.

Further, in this embodiment, a flange 33 is attached to the outer edge of the end of the ball holder 27 that receives one end of the springs 38 to 41.
Although 34 are provided, these may be provided at the inner edge of the circular tube.

Further, in this embodiment, although the guide rods 21 and 22 at both ends of the plunger 16 are movably supported with respect to the cylinder IT by two bearings 25 and 26 using balls 31 and 32, only one bearing may be replaced with other bearings.

For example, instead of the bearing 25 in the embodiment, a spring receiver 45
A general-purpose bearing may be provided to support the guide rod,
Alternatively, it is also possible to simply provide a guide hole.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the displacement vs. control signal characteristics of the electro-mechanical converter using the solenoid coil of the present invention and the conventional solenoid coil, and Figure 2 is a diagram showing the power steering of the electro-mechanical converter using the solenoid coil of the present invention. FIG. 3 is a partially cutaway perspective view showing a specific example of the ball holder shown in FIG. 2. FIG. 10...Flow control device, 12...Servo valve including electro-mechanical converter, 14...Power steering, 15...Flow rate controller, 16...Plunger,
17...Cylinder, 19...Solenoid coil, 21, 22-...Guide rod, 23...Needle control valve, 25.26...Bearing, 27...
Ball holder, 31, 32...Ball, 38, 3
9;40.41...spring, 53...orifice.

Claims (1)

[Scope of utility model registration request] An electro-mechanical converter in which a plunger is housed in a cylinder, a solenoid coil is wound around the outer periphery of the cylinder, and the plunger is moved in an axial direction in accordance with a control signal supplied to the solenoid coil. is loosely fitted into the cylinder, and guide rods extending in the axial direction from both ends of the plunger are movably supported in the cylinder via bearings, and at least one of these bearings is connected to the plunger. It is characterized by comprising a plurality of balls interposed between the inner walls of the cylinder around the guide rod, a ball holder that holds the balls, and a pair of springs that press and support the ball holders from both sides in the axial direction. Electromechanical converter using a solenoid coil.