JP2846249B2 - Piston position detection switch and piston position detection device for cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston position detecting switch and a piston position detecting device for a cylinder.
More specifically, the present invention relates to a piston position detection switch and a piston position detection device in a cylinder for detecting a piston at an intermediate position in an air cylinder or the like.

[0002]

2. Description of the Related Art Conventionally, for example, in a production line or the like,
There are air cylinders that can be stopped at a plurality of intermediate positions to stop the work at a plurality of positions. In this air cylinder, the position of the piston is detected by a magnet provided on the piston by a magnetic detection switch such as a reed switch provided outside the cylinder tube. And
When a detection signal is output from the magnetic detection switch, brakes such as a brake valve and a mechanical brake are actuated based on the detection signal to apply a brake to the movement of the piston.

The position where the braked piston actually stops is determined by the time delay between when the magnetic switch outputs a detection signal and when the brake is actuated and the inertia of the load, piston rod, etc. The position overruns from the position where the detection signal is output.

The overrun amount increases as the load and the piston speed increase, and has a certain range of variation. Normally, the overrun amount of the piston is expected to be within a detection range in which the detection switch can still detect the stopped piston. That is, the stopped piston needs to be continuously detected by the magnetic detection switch. That is, when the overrun amount of the piston exceeds the detection range of the magnetic detection switch, the magnetic detection switch is prevented from being unable to detect the stopped piston. However, if the overrun amount of the piston increases as a result of increasing the load or the piston speed, the piston may not stop within the detection range of one magnetic detection switch. As a result, the stopped piston cannot be detected by the magnetic detection switch.

For example, a programmable controller is used as a control circuit for operating the brake by inputting the detection signal of the magnetic detection switch. In this case, the input to the programmable controller is performed every scan time. Done in Therefore, the time width of the detection signal of the piston needs to be longer than the scan time. However, when the moving speed of the piston increases, the time width of the detection signal that can be output from the magnetic detection switch in a predetermined detection range decreases. As a result, the time width of the detection signal becomes shorter than the scan time,
The controller may not be able to input the detection signal.

As a method for solving the above problems,
It is conceivable to widen the detection range of the magnetic detection switch. However, since the detection range of one magnetic detection switch is limited, in order to widen the detection range, FIG.
As shown in (b), it is conceivable to dispose a plurality of magnetic detection switches 21 in the direction of movement of the piston with respect to the cylinder tube T. According to this arrangement method,
Since the detection range of each magnetic detection switch 21 is shifted in the movement direction of the piston, a wide detection range can be obtained as a whole. In the case of this method, when the piston is detected within the detection range of the first magnetic detection switch 21, the brake is operated based on the detection signal output from the magnetic detection switch 21. Then, the piston stops within the detection range of any one of the magnetic detection switches 21, and the stop of the piston is confirmed by the detection signal output from the magnetic detection switch 21. As described above, when a plurality of magnetic detection switches 21 are used, the output of each magnetic detection switch 21 is input to a separately provided signal processing circuit unit, and the signal processing circuit unit detects the detection signal of each magnetic detection switch 21. And outputs a detection signal which is the logical sum of Therefore, since the detection signal is continuously output from the time when the piston is detected by the first magnetic detection switch to the time when the piston stops, a substantially wide detection range can be obtained. The control circuit detects the operation of the brake and the stopped piston based on the detection signal.

[0007]

However, the method of arranging a plurality of magnetic detection switches 21 outside the cylinder tube is substantially impossible when the outer diameter of the cylinder is small. Also, a plurality of magnetic detection switches 21
In the case where is mounted, the efficiency of use of the space around the cylinder is deteriorated, so that it may not be possible in the manufacturing process.
Further, a signal processing circuit unit for generating a logical sum of the detection signals output from the plurality of magnetic detection switches must be provided, and an extra space is required for the circuit, so that the installation is not easy.

As another problem, when a wide detection range is obtained by using a plurality of magnetic detection switches 21, the detection range for detecting a stopped piston is widened. As a result, when stopping the piston in a narrow range with high accuracy, it becomes impossible to detect the piston stopped in the detection range according to the accuracy. That is, there is a problem that the detection accuracy of the stopped piston becomes coarse.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to prevent a large space outside a cylinder tube from being occupied by mounting.
Further, a piston position detection switch and a piston position in a cylinder capable of detecting a piston stopped at an intermediate position of the cylinder in the stop position and a stop range distant from the stop position, and detecting with a detection accuracy according to the stop range. A detection device is provided.

[0010]

According to a first aspect of the present invention, there is provided a magnetic sensor for detecting a detected member provided on a piston which is disposed outside a cylinder and moves inside the cylinder. A first magnetic detection element having a plurality of detection elements and having a detection range for detecting the magnetic detection element at a first position; and a second magnetic detection element separated from the first position.
Thereby divided into a second magnetic detecting element of the multiple that have a detection range for detecting at a position, the first magnetic detection
The detected element is first detected by moving the
A piston position detection switch that is arranged on the output side, and the detection range of adjacent magnetic detection elements is set to overlap,
From the respective detection ranges of the second magnetic detection element, detection range setting means for setting a detection range for detecting a stopped piston, and when the piston stops within the detection range set by the detection range setting means, And a piston stop determination means for outputting a detection signal, wherein the piston position detection switch, the detection range setting means and the piston stop determination means are accommodated in one case.

The invention described in claim 2 is the same as the invention described in claim 1.
In the piston position detection device in the cylinder described
Detection range setting means is provided for each magnetic detection element.
Input of the output of the corresponding magnetic sensing element to the OR circuit
Changeover switch to select piston and judge piston stop
The means was an OR circuit.

[0012] Further, the invention according to claim 3 is characterized in that :
A piston that is located outside and moves inside the cylinder
Provide multiple magnetic sensing elements to detect the provided sensing members
The brake is applied to the piston
First magnetic detection element having a detection range for detecting by position
Child and the range where the braked piston stops
Division into a plurality of second magnetic detection elements included in the detection range
At the same time, the detection range of adjacent magnetic sensing elements
It was housed in one case.

[0013]

[0014]

Therefore, according to the first aspect of the present invention, since a plurality of magnetic detecting elements are housed in one case, each magnetic detecting element is housed independently in the case. In comparison with the above, the number of parts is omitted and the space use efficiency is improved. The piston is detected at a first position within a detection range of the first magnetic detection element, and is detected at a second position within a detection range of the second magnetic detection element, which is separated from the first position. Is done.
As a result, the piston is detected in a wide range. Also, detection
Each detection range of the second magnetic detection element is set by the range setting means.
Set detection range to detect piston stopped from
Is done. Then, the piston is set within the set detection range.
Stops, the piston stop judgment means outputs a detection signal
I do. As a result, the detection range for detecting the stopped piston
Can be changed. In addition, piston position detection
Switch, detection range setting means and piston stop determination means
Each magnetic sensing element is housed in one case.
The magnetic detection switches housed in the case independently of each other
Provide detection range setting means and piston stop judgment means
The number of parts is reduced and the space is
The use efficiency of the tool is improved.

According to the second aspect of the present invention, detection is performed.
The range is set by the changeover switch. As a result,
The detection range of the piston
Or the sum of each detection range. This result
As a result, if the detection range is narrowed,
Tons can be detected with corresponding accuracy.

According to the third aspect of the present invention, a plurality of
Of the magnetic sensing elements are housed in one case.
Each magnetic sensing element is housed independently in the case.
The number of parts is reduced compared to the magnetic detection switch
At the same time, the space use efficiency is improved. And pis
Ton at a first position within the detection range of the first magnetic sensing element.
Detected and separated from the first position, a second
It is detected at a second position within the detection range of the magnetic detection element.
As a result, the piston is detected in a wide range. in addition,
The moving piston is within the detection range of the first magnetic sensing element.
The detected and stopped piston is detected by the second magnetic detecting element.
Detected within the outgoing range. That is, the stopped piston shakes.
Detection of the first magnetic detection switch for detecting
Detection range of the second magnetic detection element independent of the output range
Is detected within. As a result, the detection range must be increased.
Can be.

[0017]

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a piston position detecting device for a cylinder will be described below with reference to FIGS.

As shown in FIG. 4, the piston position detecting device 1 is mounted outside the tube T of the air cylinder Sc. The piston position detection device 1 detects a magnet M as a detected member attached to the piston P, and outputs a detection signal to the control circuit unit C. Control circuit section C
Operates the brake valve V to drive the brake Q of the air cylinder Sc.

As shown in FIG. 2, a pair of upper and lower substrates 3 and 4 arranged at opposing positions are provided in a case 2 of the piston position detecting device 1. A magnet detector 5 is formed on the lower surface of the lower substrate 3. A signal processing circuit section 6 is formed on the upper surface of the upper substrate 4.

The magnet detector 5 is fixed with four first to fourth reed switches S1 to S4 such that the outer peripheral surfaces thereof are in contact with each other. Also, each reed switch S
1 to S4 are sequentially arranged at positions shifted by the same length in the length direction. That is, as shown in FIG. 3, the rear end of the detection range of the first reed switch S1 and the front end of the detection range of the second reed switch S2 overlap, and the rear end of the detection range of the second reed switch S2 and the third reed switch S2 overlap. The front end of the detection range of the switch S3 is overlapped. The detection ranges of the first reed switch S1 and the third reed switch S3 are arranged so as not to overlap. Further, the rear end of the detection range of the third reed switch and the front end of the detection range of the fourth reed switch are overlapped. Also, the second reed switch S2 and the fourth
The detection ranges of the reed switch S4 are arranged so as not to overlap. As a result, the four reed switches S1 to S
4 forms a wider detection range.

The lower surface of the case 2 is a detection surface 2a which is in contact with the outside of the cylinder tube T. Accordingly, each of the reed switches S1 to S4 detects the magnet M provided on the piston P via the detection surface 2a and the cylinder tube T. In this embodiment, the first reed switch S
1, a first magnetic detecting element is configured, and second to fourth reed switches S2 to S4 configure a second magnetic detecting element.

The signal processing unit 6 includes an OR circuit 7, light emitting diodes 8, 9, zener diodes 10, 11, a resistor 12,
13. Changeover switches Sw1 to Sw4 are provided.
At a position on the upper surface of the case 2 opposite to the changeover switches Sw1 to Sw4, a window 2a for switching the changeover switches Sw1 to Sw4 is formed. A window 2b for viewing the light-emitting portions of the light-emitting diodes 8, 9 from the outside of the case 2 is provided at a position on the upper surface of the case opposite to the light-emitting diodes 8, 9.
Are formed.

FIG. 1 shows an electric circuit of the piston position detecting device 1. One end of each of the reed switches S1 to S4 is connected to a positive side of a DC power supply (not shown). The other end of the first reed switch S1 is connected to the resistor 12 and the light emitting diode 8
Is connected to the output terminal A via The output terminal A is connected to the control circuit section C (shown in FIG. 4) provided outside the piston position detecting device 1. In addition, a zener diode 10 is connected in parallel to the series circuit of the resistor 12 and the light emitting diode 8 with the anode on the light emitting diode 8 side and the cathode on the resistor 12 side. Therefore, the first
When the reed switch S1 detects the piston P and turns on, the light emitting diode 8 emits light and the output terminal A goes from a low potential to a high potential.

The other end of each of the reed switches S1 to S4 is connected to the input side of the OR circuit 7 via a changeover switch Sw1 to Sw4, respectively. The output side of the OR circuit 7 is connected to the output terminal B via the resistor 13 and the light emitting diode 9. The output terminal B is connected to the control circuit section C. The zener diode 11 is connected in parallel to the series circuit of the resistor 13 and the light emitting diode 9 with the anode on the light emitting diode 9 side and the cathode on the resistor 13 side. Therefore, the corresponding changeover switches Sw1 to Sw
When any one of the reed switches S1 to S4 in which the switch 4 is closed detects the piston P and turns on, the light emitting diode 13
Emits light, and the output terminal B changes from a low potential to a high potential.

When the piston position detecting device 1 is mounted on the air cylinder Sc, as shown in FIG.
a is brought into contact with the outside of the tube T of the air cylinder Sc.
At this time, the first reed switch S1 first moves the piston P in the moving direction of the piston P to apply the brake.
Of the piston position detecting device 1 in the direction in which the piston P is detected, and the detection range of the first reed switch S1 is
To be placed at the position where the brake is to be applied. That is, in FIG. 4, in order to apply a brake when the piston P moves from the right side to the left side, the piston position detecting device 1 sets the detection range of the first reed switch S1 to the right side and the detection range of the fourth reed switch S4. Is mounted in the direction arranged on the left side.

When a high-potential voltage is output from the output terminal A, the control circuit C operates the brake valve V to drive the brake Q to apply a brake to the movement of the piston P.
The control circuit C determines that the piston P has stopped within a predetermined stop range if a high-potential voltage has been output from the output terminal B when a predetermined time has elapsed since the brake Q was operated. Thus, the following operation is performed by the air cylinder Sc.

Next, the operation of the piston position detecting device configured as described above will be described. First, the piston position detecting device 1 is connected to the cylinder tube T of the air cylinder Sc.
Attach to That is, the detection surface 2a is connected to the cylinder tube T
, And the first reed switch S1 first turns the piston P in the direction in which the piston P is detected with respect to the moving direction of the piston P to apply the brake. Further, the detection range of the first reed switch S1 is arranged at a position where the piston P is to be braked. Then, in this embodiment, all the changeover switches Sw1 to Sw4 are closed. Therefore, as shown in FIG. 3, the entire detection range is a logical sum of the detection ranges of the reed switches S1 to S4. As shown in FIG. 3, when the piston P moves and the magnet M enters the detection range of the first reed switch S1, the first reed switch S1 is turned on. As a result, the light emitting diode 8
Is applied with the power supply voltage, the light emitting diode 8 emits light. At this time, since the zener diode 10 is connected in parallel to the resistor 12 and the light emitting diode 8, a large voltage is not applied to the resistor 12 and the light emitting diode 8 when the first reed switch S1 is turned on. As a result, damage to the resistor 12 and the light emitting diode 8 is prevented. At the same time, a high potential voltage is output from the output terminal A to the control circuit section C, and the control circuit section C operates the brake Q via the brake valve V based on this voltage. As a result, the piston P is braked.

When the first reed switch S1 is turned on, the power supply voltage is also applied to the light emitting diode 9. As a result, the light emitting diode 9 emits light. At the same time, a high potential voltage is output from the output terminal B.

The brake causes the piston P to overrun from the position detected by the first reed switch S1 and
To stop within any of the detection ranges of the fourth to fourth cylinder switches S1 to S4. During this time, the first to fourth reed switches S1
Since any one of S4 to S4 is turned on, the output side of the OR circuit 7 remains active, and the light emitting diode 9 remains in a light emitting state. Further, a high-potential voltage remains output from the output terminal B. As a result, the control circuit unit C determines that the piston P has stopped within the detection range of the first to fourth reed switches S1 to S4, and shifts to the next operation. At this time, if the stop position of the piston P exceeds the detection range of the first reed switch S1, the first reed switch S1 is turned off, so that the light emitting diode 8 does not emit light.

When the overrun amount of the piston P becomes excessive, the piston P is switched to any of the reed switches S1 to S4.
Stops at a position outside the detection range of. As a result, the output of the output terminal B becomes low potential. In this case, the control circuit unit C determines that the piston P has stopped beyond the detection range, and suspends the transition to the next operation.

As described above, according to the piston position detecting device 1 of the present embodiment, a plurality of reed switches S1 to S4 are provided in one case 2, and the first reed for detecting the piston P and operating the brake is provided. With respect to the detection range of the switch S1, the detection ranges of the second reed switches S2 to S4 for detecting the stopped piston P are arranged at positions sequentially shifted from each other, and are arranged such that adjacent ends overlap. or,
Change each reed switch S1 to S4 to a changeover switch S
It was connected to the OR circuit 7 via w1 to Sw4. And
In use, the changeover switches Sw1 to Sw4 are all closed, and the stop of the piston P is detected in the range of the sum of the detection ranges of the reed switches S1 to S4. Therefore, the first
Even if the piston P greatly overruns from the position detected by the reed switch S1, the piston P stops within the detection range, so that the stopped piston P can be detected.

According to the piston position detecting device 1 of this embodiment, the changeover switch S of each of the reed switches S1 to S4 is used.
By selecting and closing w1 to SW4, the detection range for detecting the stop of the piston P can be changed. For example, by closing only the changeover switch Sw3 corresponding to the third reed switch S3, the detection range for detecting the stop of the piston P is limited to only the detection range of the third reed switch S3, as shown in FIG. You can also. Therefore, when the piston P is stopped within a narrow range with high accuracy, the piston P can be detected with high detection accuracy according to the stop range.

It should be noted that the present invention is not limited to the above embodiment, but can be configured as follows. (1) Although the present invention is applied to the piston position detecting device 1 provided with the magnet detecting unit 5 and the signal processing unit 6 in the case 2, it is also possible to use only the magnet detecting unit 5 as a piston position detecting switch provided in the case 2. Good. In this case, the signal processing unit 6 is provided outside the piston position detection switch, and a logical sum of the detection signals of the respective reed switches S1 to S4 is created and output to the control circuit unit C.

(2) In the above embodiment, the reed switches S1 to S4 are connected to the OR circuit 7 to widen the entire detection range, but as shown in FIG. May be configured to be connected. According to this configuration, for example, as shown in FIG. 7, by closing only the changeover switches Sw3 and Sw4 of the reed switches S3 and S4, the detection range for detecting the stop of the piston P is detected by the reed switches S3 and S4. The range can be limited to a common range. As a result, the range in which the stop of the piston P is detected can be narrower than the range in which the reed switches S1 to S4 are detected. Therefore, when the piston P is stopped with high accuracy within a range narrower than the detection range of each of the reed switches S1 to S4, the piston P can be detected with high detection accuracy according to the stop range.

By operating each of the reed switches S2 to S4 independently, the detection range for detecting the stopped piston P can be moved. Therefore, even for the piston P of the air cylinder Sc having a different overrun amount, the piston P can be detected with high accuracy by changing the detection range according to the overrun amount.

(3) In the above embodiment, the first reed switch S1 is connected to the output terminal A,
The piston P was detected in the detection range of No. 1 and the brake was operated. The first reed switch S1 and the fourth reed switch S4 are connected to the output terminal A via the changeover switch. Then, the reed switches S1 and S4 for detecting the piston P for braking are connected to the output terminal A in accordance with the moving direction in which the piston P is braked. According to this configuration, the piston position detecting device 1 that detects the piston P in both movement directions can be provided. In this case, when attaching the piston position detecting device 1 to the air cylinder Sc, it is not necessary to consider the direction.

(4) The number of reed switches S1 to S4 may be two or three, or may be five or more. (5) The magnetic detection switches are reed switches S1 to S
4, not only Hall elements, magnetoresistive elements (semiconductor type, ferromagnetic type), magnetic diodes, magnetic transistors, SQ
A solid state magnetic sensor such as a UID (superconducting quantum interferometer) may be used.

(6) The light emitting diodes 12, 13 may not be provided in the piston position detecting device 1, but may be provided in the control circuit section C or the like. Also, it does not have to be provided. (7) Not only when the piston P is stopped, the stopped piston P may be moved within the detection range of the first reed switch S1 and stopped within the detection range of the second to fourth reed switches S2 to S4. it can. That is, the piston P detected by the first reed switch S1 is moved by a predetermined amount and stopped. Then, the stopped piston P is
To the fourth reed switch S2 to S4.

[0040]

[0041]

In this specification, means and members according to the present invention are defined as follows. (1) The detection range of the magnetic detection element refers to a movement range of the piston in which the magnetic detection element attached to the outside of the cylinder tube can detect a magnet provided on the piston moving inside the cylinder.

(2) The case accommodates a plurality of magnetic detecting elements or a piston detecting section, a detecting range setting means, and a piston stop determining means composed of a plurality of magnetic detecting elements. It means that the detection element can be attached so that the detection target member can be detected.

[0044]

As described in detail above, according to the first to third aspects of the present invention, the mounting does not occupy a large space outside the cylinder tube and stops at the intermediate position of the cylinder. The piston can be detected at the stop position and at a stop range distant from the stop position, and can be detected with detection accuracy corresponding to the stop range.

According to the second aspect of the present invention, the detection range can be changed to only the detection range of each magnetic detection element or the sum of the detection ranges. Therefore, when the piston is stopped with high accuracy in a narrow range, the piston can be detected in a narrow detection range including the detection range of one magnetic detection element.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a circuit configuration of a piston position detecting device according to an embodiment of the present invention.

FIG. 2A is a front sectional view showing a piston position detecting device, and FIG. 2B is a side sectional view of the same.

FIG. 3 is an explanatory diagram showing a relationship between a detection range of each reed switch and an output signal.

FIG. 4 is a front view showing an air cylinder to which a piston position detecting device is attached.

FIG. 5 is an explanatory diagram showing a relationship between a detection range of a reed switch and an output signal.

FIG. 6 is a circuit diagram showing a circuit configuration of another example of the piston position detecting device.

FIG. 7 is an explanatory diagram showing a relationship between a detection range of each reed switch and an output signal.

FIG. 8A is a front view showing a cylinder switch mounted on a conventional air cylinder, and FIG. 8B is a side view of the same.

[Explanation of symbols]

Reference numeral 2 denotes a case, 5 denotes a magnet detection unit as a piston position detection switch, 7 is an OR circuit, M is a magnet as a member to be detected, S1 is a first as a first magnetic detection element.
Reed switches, P ... pistons, S2 to S4 ... second to fourth reed switches as second magnetic detecting elements, Sc ...
Cylinders, Sw1 to Sw4 ... changeover switches.

Claims (3)

(57) [Claims] 1. A magnetic detecting element (S1) arranged outside a cylinder (Sc) and detecting a detected member (M) provided on a piston (P) moving inside the cylinder (Sc).
To S4), and the magnetic sensing element (S1 to S4)
A first magnetic detection element (S1) having a detection range for detecting the second position at a first position, and a second magnetic detection element (S1) separated from the first position.
While it divided into a second magnetic detection element number multiple that have a detection range for detecting at position (S2 to S4), before
The first magnetic sensing element (S1) is moved by the piston (P).
On the side that first detects the detected member (M)
And a piston position detection switch (5) in which the detection ranges of adjacent magnetic detection elements (S1 to S4) overlap each other, and a detection position of each of the second magnetic detection elements (S2 to S4). Detection range setting means (Sw1 to Sw4) for setting a detection range for detecting the stopped piston (P); and the piston (P) stops within the detection range set by the detection range setting means (Sw1 to Sw4). And a piston stop determination means (7) for outputting a detection signal, wherein the piston position detection switch (5), the detection range setting means (Sw1 to Sw4) and the piston stop determination means (7) are combined into one case (2). A piston position detecting device for a cylinder housed in the housing. 2. A piston in a cylinder according to claim 1.
In the ton position detection device, the detection range setting means is provided for each magnetic detection element (S1 to S4).
Corresponding to the magnetic detection elements (S1 to S4)
For selecting input of OR output to OR circuit (7)
Switches (Sw1 to Sw4) to determine piston stop
The means is a piston in a cylinder that is an OR circuit (7)
Position detection device. And a cylinder disposed outside the cylinder.
Provided on piston (P) that moves inside of Linda (Sc)
The magnetic detection element (S1) for detecting the detected member (M)
To S4) to detect the magnetic detecting elements (S1 to S4) at positions where the piston (P) is braked.
A first magnetic detection element (S1) having a detection range of
Detects the range where the piston (P) is stopped
A plurality of second magnetic sensing elements (S2 to S4) included in the range;
And the adjacent magnetic sensing elements (S1 to S1)
4) One case so that the detection ranges overlap each other
(2) Piston position detection in the cylinder housed inside
switch.