JPH0275901A - Stroke sensor - Google Patents

Abstract

PURPOSE:To simplify the structure and improve the reliability of a stroke sensor by providing a magnet to a rod in a united state, a magnetism transmission means along the moving area of the magnet, and a magnetic converting element in the magnetism transmission means. CONSTITUTION:When a power piston 35 makes reciprocating motions, a permanent magnet 40 is moved rightward through rods 50 and 44 and the areas of the magnet 40 and yoke 41 facing to each other increase and, at the same time, the distance between the magnet 40 and yoke 41 becomes shorter. Therefore, the density of the magnetic flux inside the magnetic circuit constituted of the magnet 40, yoke 41, and a Hall element 42 gradually increases. The density of the magnetic flux is converted into a voltage by means of the element 42 and the voltage is inputted to a controller through an amplifier 43. At the controller, the value of the inputted voltage is compared with the preset actuation starting and actuation completing values of each element and, when the voltage value reaches the set values, command signals are outputted to the drive circuit of each element. Thus the structure can be simplified and the reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a stroke sensor, and more particularly to a non-contact type stroke sensor.

b. Prior art FIG. 7 shows a clutch actuator using a stroke sensor, FIG. 8 shows a time chart of the clutch actuator, and FIG. 9 shows a stroke sensor of the clutch actuator. In FIG. 7, the clutch lever 12 is a cylinder for operating the clutch lever 1, and the piston 3 disposed in the cylinder 2 and the clutch lever 1 are connected via a bushing rod 4. interconnected.

One end of a tube 6 for supplying and discharging compressed air to and from a pressure chamber 5 within the cylinder 2 is connected to the cylinder 2 . At the other end of the tube 6 is a first solenoid valve 7. A second solenoid valve 8 and a third solenoid valve 9 are connected in parallel. The first solenoid valve 7 is connected to the near reservoir 11 by a passage 10, and the second solenoid valve 8 and the third solenoid valve 9 are connected to exhaust tubes 12,13.

The first and second solenoid valves 7 and 8 are each composed of a normally closed three-way solenoid valve, and the third solenoid valve 9
consists of magnetic valves on three sides that are normally open. Therefore,
When the first solenoid valve 7 is in a non-energized state, the near reservoir 11 and the pressure chamber 5 are cut off, and when the first solenoid valve 7 is energized, the near reservoir 11 and the pressure chamber 5 are communicated with each other, and the compressed air in the near reservoir 11 is is supplied to the pressure chamber 5 of the cylinder 2,
This pressure causes the piston 3 within the cylinder 2 to move forward in the right direction in FIG. 7, thereby disengaging the clutch. Further, when the second solenoid valve 8 is in a non-energized state, the pressure chamber 5 and the outside (atmospheric pressure) are cut off, and when it is energized, the pressure chamber 5 is opened to the outside, and the pressure chamber 5 is opened to the outside. 12
The piston 3 in the cylinder 2 is discharged to the outside from the seventh cylinder.
The clutch is connected by moving back to the left in the figure. Furthermore, when the third electromagnetic valve 9 is in an excited state, the pressure chamber 5 is cut off from the outside (atmospheric pressure), and when it is demagnetized, the pressure chamber 5 is opened to the outside.

Above 1. The opening and closing of the second and third solenoid valves 7° 8 and 9 are controlled by a controller 14. This controller 14 receives a detection signal from a sensor 15 that detects the stroke position of the bushing rod 4, an n recognition signal issued from the range input confirmation sensor 17 of the change lever 16, an accelerator depression angle detection signal detected by the accelerator 18, etc. is now entered.

Next, the operation of the clutch actuator described above is performed in the eighth step.
This will be explained with reference to the figures. For example, if the change lever 16 is D
When placed in the range (automatic shift position), confirmation sensor 1
A confirmation signal is input to the controller 14 from 7. When this confirmation signal is input to the controller 14, the first solenoid valve 7 and the third solenoid valve 9 are excited (ON), and the first solenoid valve 7 and the third solenoid valve 9 are excited (ON).
The third solenoid valve 7 is opened, and the third solenoid valve 9 is closed. Therefore, compressed air from the near reservoir 11 is supplied to the pressure chamber 3 of the cylinder 2. When compressed air is supplied to the pressure chamber of the cylinder 2, the piston 3 within the cylinder 2 moves forward to the right in FIG. 7, and the clutch is disengaged. At this time, the controller 14 checks the signal from the sensor 15 at predetermined intervals, and when it determines that the clutch has been stroked to the point where it is completely disengaged, it de-energizes (OFF) the first solenoid valve 7 and closes it. .

When the clutch is disengaged in this way, controller 1
A command signal from 4 operates an actuator (not shown), thereby shifting the transmission from a starting gear, such as neutral, to second gear. When the accelerator is depressed by a predetermined amount, a command signal is output from the controller 14 to the second solenoid valve 8, and the second solenoid valve 8 is turned on and opened, and the compressed air in the pressure chamber 5 of the cylinder 2 is released. Exhaust boat 12
is discharged to the outside. When the compressed air in the pressure chamber 5 is discharged to the outside, the bushing rod 4 moves back to the left in FIG. 7, and the clutch is connected. At this time, when the bushing rod 4 moves back to a position where the clutch begins to be in a half-clutch state (indicated by reference numeral B in FIG. 8), that position is confirmed by the controller 14 via the sensor 15.

Then, the second electromagnetic valve 8 is alternately controlled to θN-0FF by the command signal from the controller 14, and the clutch is smoothly connected.

When the bushing rod 4 moves back to the point where the controller 14 confirms that the clutch engagement is almost complete based on engine speed, vehicle speed, etc. (indicated by C in FIG. 8), a command signal from the controller 14 The second solenoid valve 8 and the third solenoid valve 9 are turned off simultaneously. Second
The compressed air in the pressure chamber 5, which had been discharged to the outside by the third solenoid valve 8, is subsequently discharged to the outside by the third solenoid valve 9, and the return movement of the bush loft 4 is completed.

C1 Problems to be Solved by the Invention Incidentally, the actual stroke detection of the power piston 3 in the clutch actuator is performed by a variable resistance type stroke sensor 20 as shown in FIG. This stroke sensor 20 is connected to the power piston 3
The detection rod 22 includes a variable resistor 21 installed at a position facing the variable resistor 21 and a detection loft 22 that transmits the amount of movement of the power piston 3 to the variable resistor 21. The detection rod 22 has one end connected to the brush of the variable resistor 21. It is engaged with the holder 23, and the other end is brought into contact with the atmospheric pressure side surface 3a of the power piston 3 by the urging force of the return spring 24. And power piston 3
When moving to the right in FIG. 9, the detection rod 22 is pushed in the same direction by the power piston 3, and the brush holder 23 is thereby moved.

Therefore, the brush 25 of the brush holder 23 slides on the resistor 26, and the amount of movement of the brush holder 23 is converted into an electrical quantity such as voltage, and the electrical quantity is input to the controller 14 via the cable 27. .

However, in the clutch actuator described above, one end of the detection rod 22 is connected to the brush holder 23 and the other end is always in contact with the power piston 3, so vibrations from the engine etc. may cause the power piston 3° and the detection rod 22 to move. It is transmitted to the brush holder 23 via the brush holder 23. Therefore, in the above clutch actuator, the brush 25 slides on the resistor 26 more than necessary, which causes wear of the brush 25 and the resistor 26.

In order to solve these problems, it would be possible to use a known non-contact stroke sensor, but it is expensive, has a complicated structure, has low reliability, and
In particular, there are no suitable ones because they cannot withstand use in harsh environments such as automobiles.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a stroke sensor that has a simple structure, high reliability, excellent durability, and is inexpensive.

d. Means for Solving the Problems The stroke sensor of the present invention has a magnet integrally installed in the rod, a magnetic transmission means along the moving range of the magnet, and a magnetic transmission means in the magnetic transmission means. A magnetoelectric conversion element is provided, a change in magnetic flux density within the magnetic transmission means due to the movement of the magnet is converted into an electric quantity by the magnetoelectric conversion element, and the position of the object to be measured is determined based on the electric quantity. I'm trying to detect it.

e. Example An example of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 shows the main parts of an automatic clutch actuator equipped with a stroke sensor of the present invention, and FIG. 2 shows the main body of an automatic clutch actuator equipped with the stroke sensor. As shown in FIG. 2, this actuator is a power cylinder 30. It is composed of a hydraulic cylinder 31 and a solenoid valve unit 32.

The power cylinder 30 includes a cylindrical cylinder 34 attached to a housing 33 and a power piston 35 inserted into the cylinder 34 so as to be able to reciprocate. This power piston 35 is always urged in the backward movement direction (direction of arrow d in FIG. 2) by a return spring 37 disposed in the atmospheric pressure chamber 36, but compressed air is supplied to the pressure chamber 38. Then, the power piston 35 moves forward in the direction of arrow e in FIG. 2 against the return spring 37. This power cylinder 30 is equipped with a stroke sensor 39 on the side of the housing 33. This sensor 39 is for detecting the stroke position of the power piston 35.
As shown in FIG. 3 and FIG. 3, a permanent magnet 40 is installed integrally with the power piston 35, a yoke 41.41 is placed on both sides along the movement range of the permanent magnet 40, and the yoke 41.41 A magneto-electric transducer, for example, a Hall element 42 installed at the meeting point of the and a controller (not shown) that determines the position of the permanent magnet 40. The permanent magnet 40 is fixed to the rear end of a piston rod 44 made of aluminum. piston rod 44
A piston 45 is integrally molded at the tip of the housing 46, and the piston 45 is slidably inserted into a cylinder 47 of a housing 46 formed of aluminum casting. The piston rod 44 also has a groove 48 along the generatrix.
A guide pin 49 embedded in the housing 46 is fitted into the groove 48 . The piston rod 44 contacts the power piston 35 via a rod 50 and is pressed by a spring 51 disposed between the permanent magnet 40 and the yoke 41. The yoke 41 is made of a soft magnetic material such as silicon iron, and is attached to the housing 4 by appropriate means such as resin molding.
It is fixed at 6. As shown in FIGS. 4(a) and 4(b), the shape of this yoke 41 is such that the width -1 at one end is narrower than the width -8 at the other end, and gradually increases as it goes from one end to the other end. ing. In the example shown in FIG. 4, the slope between b and yoke 4 is thicker than the slope between 8 and 0.
1.41, the distance H21 between them at one end is greater than the distance M2 at the other end, and gradually decreases as one goes from one end to the other. In the example shown in Figure 4, the reduction ratio between b and 0 is thicker than the reduction ratio between 8 and 0 (
It has become.

Next, the hydraulic cylinder 31 includes a cylindrical cylinder 52 screwed onto the housing 33, and a cylinder 52 that is threaded onto the housing 33.
It consists of a first relay piston 53 and a second relay piston 54, each of which is slidably disposed therein. The first relay piston 53 is connected to a piston rod 55 of the power piston 35, and the second relay piston 54 is connected to a clutch lever (not shown) by a bushing rod 56.
is connected to. Compression springs 57 and 58 are disposed between the first relay piston 53 and the second relay piston 54, and the compression springs 57 and 58 constantly move the second relay piston 54 in the forward direction (see Fig. 2). (in the right direction). Further, an oil chamber 59 is formed between the first relay piston 53 and the second relay piston 54, and the bushing rod 56 or the second relay piston 54 moves in the backward direction as the clutch wears. , the oil chamber 59
It is configured so that it can be absorbed automatically when the volume changes. Therefore, there is no need to attach a manual length adjustment device such as a turnbuckle to the bushing rod 56 (there is an advantage that maintenance of the actuator requires almost no effort. Furthermore, an air bleed plug 60 is attached to the cylinder 52, When air accumulates in the oil chamber 59, this air can be discharged to the outside through an air vent plug 60.

A passage 61 is formed inside the first relay piston 53 along its axial direction. This passage 61 communicates with a passage 62 formed within the housing 33, and this passage within the housing 33 is connected by a tube 63 to an oil reservoir (not shown). Note that an air vent plug 64 is attached to the upper part of the housing 33, and the air that has entered the passage 62 is removed from the air vent plug 64.
It is designed so that it can be discharged to the outside. A valve body 65 is disposed in the middle of the passage 61 of the first relay piston 53, and this valve body 65 is always urged in the closing direction by a compression spring 66. On the other hand, a cylindrical portion 67 is formed at the rear end of the first relay piston 53;
A slit 68 is formed in the rear end portion of the relay piston 53 along the diameter direction. A U-shaped yoke 69 is inserted into this slit 68, and when the yoke 69 presses the rear end of a rod 70 connected to the valve body 65, the valve body 65 opens against the compression spring 66. It is configured as follows. A spring 71 is disposed on the outer periphery of the cylindrical portion 67, and connects the piston rod 55 and the first relay piston 53.
The connecting bin 72 connecting the two is configured so that it cannot be pulled out.

Note that a disk-shaped plug 73 is press-fitted into the inner circumference of the cylindrical portion 67 of the first relay piston 53.
3 prevents the yoke 69 from coming out of the slit 68.

Next, the configuration of the solenoid valve unit 32 will be explained.

This solenoid valve unit 32 has a first solenoid valve 75 . Second solenoid valve 76 and third solenoid valve 77
This is the one with the . The first solenoid valve 75 is a normally closed solenoid valve, and an input port and an output port (not shown) are communicated with the compressed air supply lower 8 and the compressed air discharge lower 9, respectively. The compressed air supply lower 8 is connected to a near reservoir (not shown) by a tube 80, and the compressed air discharge lower 9 is connected to the pressure chamber 38 of the power cylinder 30 by a tube 81. And this first
When the electromagnetic valve 75 is excited, the compressed air supply lower 8 and the compressed air discharge lower 9 are communicated with each other, and as a result, compressed air from the near reservoir is supplied to the pressure chamber 38 of the power cylinder 30.

The second electromagnetic valve 76 is also a normally closed electromagnetic valve, and is configured in substantially the same manner as the first electromagnetic valve 75 described above. However, in this second electromagnetic valve 76, an input port and an output port (not shown) are connected to the compressed air discharge lower 9 and one end of the vibe 82, respectively, and the pipe 8
The other end of 2 is connected to the atmospheric pressure chamber 36 of the power cylinder 30. The atmospheric pressure chamber 36 is connected to an atmospheric valve 83 attached to the upper part of the housing 33 through a passage (not shown). This atmospheric valve 83 is composed of a check valve that performs only an exhaust action, and is connected to the hydraulic cylinder 3.
The inside of the boot 84 attached to the air conditioner 1 is also connected to this atmospheric valve 83 via a tube 85. When this second solenoid valve 76 is excited, the compressed air discharge lower 9
and the atmospheric pressure chamber 36 , and as a result, the compressed air in the pressure chamber 38 is discharged to the atmospheric pressure chamber 36 , and the atmospheric valve 83
is discharged to the outside through the

The third solenoid valve 77 is a normally closed solenoid valve, and an input port and an output port (not shown) are connected to the compressed air discharge lower 9 and the atmosphere port 86, respectively. This third electromagnetic valve 77 opens the pressure chamber 38 to the atmosphere through the atmosphere port 86 in a non-energized state, and is energized to cut off the space between them.

The clutch actuator is constructed as described above. The opening and closing of the second and third solenoid valves 75 to 77 are controlled by a controller (not shown). Like conventional clutch actuators, this controller receives a detection signal from the sensor 39, a range confirmation signal from a change lever (not shown), a signal corresponding to the engine rotational speed, a signal corresponding to the amount of accelerator depression, etc. Based on these signals, the first . Second and third solenoid valves 75 to 77 are controlled to open and close. In FIG. 2, 87 is a cable of the solenoid valve unit 32, and the socket 112 of this cable 111 is connected to the controller. Further, in FIG. 1, 113 is a lead wire of the stroke sensor 39, and this lead wire 113 is connected to the controller.

The opening and closing of the electromagnetic valves 75 to 77 is controlled as shown in FIG. 8 in detail. First, when a change lever (not shown) is placed in, for example, a D range (automatic shift position), a confirmation signal confirming that the change lever has been placed is input to the controller.

When this confirmation signal is input to the controller, the first solenoid valve 75 and the third solenoid valve 77 are turned on. When the first solenoid valve 75 is turned ON, the compressed air in the near reservoir is transferred from the compressed air supply lower 8 to the compressed air discharge lower 9 to the tube 8.
This pressure causes the power piston 35 to move forward in the direction of arrow e in FIG. 2 against the compression spring 37.

On the other hand, when the third solenoid valve 77 is turned on, the pressure chamber 38
The space between the air vent 86 and the air vent 86 is closed. Therefore, the compressed air supplied to the pressure chamber 38 of the power cylinder 30 is not discharged from the atmosphere port 86 of the third electromagnetic valve 77.

When the power piston 35 moves forward in the direction of arrow e in FIG.
3 is pushed forward by the piston rod 55, and the yoke 69, which normally contacts the stopper 89 and presses the rod 70 of the valve body 65, leaves the stopper 89.

As a result, the valve body 65 is pressed against the valve seat 90 by the compression spring 66, the passage 61 of the first relay piston 53 is closed, and the hydraulic pressure 59 is sealed. Therefore, the first relay piston 5
The forward force of 3 is transmitted to the second relay piston 54 via the oil in the oil chamber 59, and the first and second relay pistons 53 and 54 move forward integrally to disengage the clutch.

Thus, when the power piston 35 moves forward, the power piston 35 moves the permanent magnet 40 to the right in FIG. 1 via the rod 50.degree. 44. Permanent magnet 40
When the permanent magnet 40 and the yoke 41 are moved to the right, the area where the permanent magnet 40 and the yoke 41 face each other increases, and the distance between the permanent magnet 40 and the yoke 41 decreases. Therefore, the permanent magnet 40
．． York 41. The magnetic flux density within the magnetic circuit constituted by the Hall element 42 gradually increases. This magnetic flux density is converted into a voltage by the Hall element 42, and the voltage is inputted to a controller (not shown) via an amplifier 43. The controller compares, for example, the input voltage value with preset operation start and end values of each element,
When the value of the voltage reaches the set value, a command signal is output to the drive circuit of each element.

Now, due to the forward movement of the power piston 35, the permanent magnet 4
0 is the position where the clutch is disengaged (indicated by symbol A in Figure 8)
When it reaches this point, the Hall element 42 detects this, and this detection signal is input to the controller. When the detection signal of the Hall element 42 is input to the controller, a command signal is output from the controller, thereby turning off the first electromagnetic valve 75.

When the first solenoid valve 75 is turned off, the supply of compressed air to the pressure chamber 38 is stopped.

When the clutch is disengaged in this manner, the transmission is operated, for example, from neutral to second gear. Then, when the accelerator is depressed by a predetermined amount, a command signal is output from the controller and the second solenoid valve 76 is turned on. At this time, the third solenoid valve 77 maintains the ON state. When the second solenoid valve 76 is turned on, the compressed air in the pressure chamber 38 of the power cylinder 30 is transferred from the tube 92 to the compressed air discharge lower 9 to the pipe 82, as in the case of the first solenoid valve 75 described above.
→ Atmospheric pressure chamber 36 → Atmospheric valve 83 and is discharged to the outside.

When the compressed air in the pressure chamber 38 is discharged to the outside, the power piston 35 receives the return force from the clutch and the return spring 3.
7 in the direction of arrow d in FIG. 1, and the first relay piston 53. The second relay piston 54 and bushing rod 56 also move back in the same direction to connect the clutch. At this time, the bushing rod 56 or the power piston 35 moves back to the position where the clutch starts to be in a half-clutch state (indicated by the symbol B in FIG. 8), and this is detected by the sensor 3.
9 detects and this detection signal is input to the controller. When the detection signal of the sensor 39 is input to the controller, the second solenoid valve 76 is alternately turned ON-OFF@? I was
The clutch is connected smoothly.

Push the bushing rod 56 or the power piston 35 until the clutch connection is completed (indicated by C in FIG. 8).
When the motor moves back, the sensor 39 detects this, and this detection signal is input to the controller.

When the detection signal of the sensor 39 is input to the controller,
The second solenoid valve 76 and the third solenoid valve 77 are simultaneously turned off. When the second solenoid valve 76 is turned off, the discharge of compressed air from the atmospheric valve 83 is stopped. On the other hand, when the third solenoid valve 77 is turned OFF, the residual pressure remaining in the pressure chamber 38 of the power cylinder 30 is discharged to the outside through the path of the tube 81 → compressed air discharge lower 9 → atmospheric port 86. Ru. At this time, since the third solenoid valve 77 is kept OFF and open until the next clutch operation, there is no risk of residual pressure remaining in the pressure chamber 38 of the power cylinder 30, and the power piston 35 moves completely backward as shown in FIG.

In addition, in the stroke sensor 39 shown in the above embodiment,
As shown in FIG. 4, the width of the yoke 41 is gradually increased from one end to the other, and the distance between the yokes 41 and 41 is increased, thereby increasing the magnetic flux density with respect to the amount of movement of the permanent magnet 40. Although the sensitivity of the stroke sensor 39 is improved by increasing the rate of change, the shape of the yoke 41 may be as shown in FIGS. 5 and 6. The yoke 41 in FIG. In this yoke 41, the width -8 at the other end is larger than that at the other end, and the convergence gradually increases from one end to the other.However, in this yoke 41, the distance between the yokes 41 and 41 is In the stroke sensor 39 using such a yoke 41, a spacer 91 made of polytetrafluoroethylene is interposed between the permanent magnet 40 and the yoke 41, so that the permanent magnet 4
0 can be guided while maintaining a uniform distance from the yoke 41. Furthermore, the yoke 41 in FIG. 6 has uniform convergence from one end to the other, and the distance between the yokes 41 and 41 is smaller than the distance Mtt+ at one end, and the distance l at the other end is smaller than the distance Mtt+ at one end. The distance gradually decreases towards the end.

Further, in the above embodiment, the Hall element 4 is used as the magnetoelectric conversion element.
However, instead of the Hall element 42, other magnetoelectric conversion elements such as a magnetoresistive element, a magnetic diode, a magnetic transistor, etc. can be used.

Further, in the above embodiment, an example was shown in which the stroke sensor of the present invention is used in a clutch actuator, but the stroke sensor of the present invention can also be used in other applications such as a vehicle height sensor for an air suspension system, an accelerator depression angle detection sensor, etc. Of course, it can also be used as a stroke sensor in a device.

r. Effects of the Invention As described above, the stroke sensor according to the present invention is composed of a permanent magnet, a yoke, and a magnetoelectric converter, and the permanent magnet and yoke, which are moving objects, are always separated from each other without causing wear. Therefore, it is highly durable, has a simple structure, and is inexpensive.Furthermore, since it performs magnetic detection, it is not affected by the external environment and is highly reliable.

[Brief explanation of the drawing]

1 to 4 show a clutch actuator using the stroke sensor of the present invention.
The figure is a longitudinal sectional view showing the stroke sensor of the clutch actuator, FIG. 2 is a longitudinal sectional view showing the main body of the clutch actuator, FIG. 3 is a perspective view conceptually showing the stroke sensor, and FIG. The figure is a side view and a plan view showing the shape of the yoke of the stroke sensor, FIGS. 5 and 6 are side views and a plan view showing other shapes of the yoke in the stroke sensor according to the present invention, and FIG. Figures 9 to 9 show conventional actuators, with Figure 7 being a conceptual diagram of the actuator, Figure 8 being a time chart showing the control status of the solenoid valve, and Figure 9 being a longitudinal section showing the stroke sensor. It is a front view. 30... Power cylinder, 31... Hydraulic cylinder, 32... Solenoid valve unit, 33... Housing, 35... Power piston, 36... Atmospheric pressure chamber, 37... Return spring , 38... Pressure chamber, 39... Stroke sensor, 40... Permanent magnet, 41... Yoke, 42... Hall element (magnetoelectric conversion element), 43... Amplifier, 44... Piston rod, 45... Piston, 46
...Housing, 47...Cylinder,
4B...Groove, 49...Guide pin, 50...Rod, 51...Spring. Figure 4 (a) Figure 5 (b) Figure 6 (b)

Claims (2)

[Claims] (1) A magnet is integrally installed on the rod, a magnetic transmission means is arranged along the movement range of the magnet, and a magnetoelectric conversion element is arranged in the magnetic transmission means, and the magnetic transmission means A stroke sensor characterized by different convergence at both ends within the moving range. (2) A magnet is integrally installed on the rod, a magnetic transmission means is arranged along the movement range of the magnet, and a magnetoelectric conversion element is arranged in the magnetic transmission means, and the magnetic transmission means is A stroke sensor characterized in that a gap between the magnet and the magnet is different within a moving range.