JPH0119366Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a potentiometer used as a sensor for detecting the operating position and operating direction of a detected object, such as a directional control valve for hydraulic equipment. be.

(Prior Art) Conventionally, this type of potentiometer has a single resistor 1, which is in sliding contact with the resistor 1, and connects an object to be detected (not shown) and a machine, as shown schematically in FIG. 1a, for example. A slider 2 is connected to the slider 2, and a change in the position of the object to be detected is detected by a change in voltage appearing at a terminal 3 electrically connected to the slider 2. That is, the first
As shown in the output characteristics in Figure b, if the horizontal axis represents the change in the position of the slider 2, if a positive voltage of, for example, 24 volts is applied to the other end of the resistor 1, one end of which is connected to the ground, the sliding When the child 2 slid from one end of the resistor 1 to the other end, the amount of sliding and the voltage appearing at the terminal 3 (vertical axis in FIG. 1b) were in a one-to-one correspondence.

Therefore, when point A shown in FIG. 1a is used as a predetermined position, for example, as a neutral position, the position of slider 2 where the voltage appearing at terminal 3 in FIG. 1b is 12 volts is used as a neutral position. When using a potentiometer, the voltage appearing at terminal 3
When Vx is 12<Vx<24, slider 2 is on the right side from neutral position A (arrow R side in Fig. 1b), and O<Vx
When <12, it was judged that it was on the left side (arrow L side in Figure 1b).

(Problem to be solved by the invention) However, according to the configuration of the above-mentioned prior art,
For example, if the potentiometer is installed in a humid environment, if water droplets adhere to the resistor 1 and the attached part becomes short-circuited, the voltage corresponding to the position of the slider 2 cannot be obtained, so the slider It becomes impossible to determine in which position and direction 2 is located with respect to the neutral position A, and in some cases, misjudgment of the direction of movement may lead to unexpected failures due to malfunction of the detected object, for example. There was a problem that there was.

(Means for Solving the Problems) The present invention has been made to solve the problems of the prior art described above, and includes a first resistor and a first conductor, each of which is linear, with a first specific position sandwiched therebetween. A first sliding resistance section connected in series, and a second sliding resistance section each connected in series.
a second sliding resistance section formed by connecting a conductor and a second resistor in series across a second specific position, and a first slider slidingly in contact with the first sliding resistance section. , a second slider that is in sliding contact with the second sliding resistance part, and the first sliding resistance part and the second sliding resistance part are connected to the first resistor body. The two conductors are installed in a cylindrical case so that they face each other, and the second resistor is opposite to the first conductor, and is located between the two sliding resistance parts and on one side in the longitudinal direction of the case. A guide shaft is provided protruding from one end of the case toward the other end, and one end of the sliding shaft that can freely slide along the guide shaft, which engages with the object to be detected, is connected to the other end of the case in a watertight manner. the first and second sliders are made to protrude to the outside in a state such that when the first specific position and the first slider come into sliding contact, the second slider and the second specific position come into sliding contact. a lead wire for attaching a second slider to the sliding shaft and outputting a signal according to a sliding contact position between the first slider and the first resistor; Lead wires for outputting signals corresponding to the sliding contact position between the child and the second resistor are respectively extended outside the case in a watertight state, thereby preventing misunderstanding of the position and direction of the object to be detected. It can be detected easily and is compact by being housed in one case.
The purpose of the present invention is to provide a potentiometer that can be easily watertight.

(Operation) The first slider and the second slider are
When the potentiometer is brought into sliding contact with a specific position, the output of the potentiometer becomes zero. When the sliding shaft is slid in one direction from the first and second specific positions, the first slider comes into sliding contact with the first resistor, and the second slider comes into sliding contact with the second conductor. When the sliding shaft is slid from the sliding contact position between the first slider and the second slider and the first and second specific positions to the other, the first slider contacts the first conductor. To,
The second slider is in sliding contact with the second resistor. Therefore, when the first slider is in sliding contact with the first resistor, only the output corresponding to the sliding contact position of the first slider is obtained, and the second slider is in sliding contact with the first resistor. When the potentiometer is in sliding contact with the resistor, only the output corresponding to the sliding contact position of the second slider is obtained, and the potentiometer always outputs the increase or decrease in the resistance value alternatively. The direction and position of the object to be detected can be determined at the same time.

(Embodiment) An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 is a longitudinal sectional view of a potentiometer according to an embodiment of the present invention, and FIG.
FIG.

Hollow cylindrical case 1 of potentiometer 10
A flange 12 is formed integrally with the case 11 at one end of the flange 12, and a shaft 15 is slidably inserted through a bush 13 and an O-ring 14 fitted inside the end. Further, a cap 16 for sealing the case 11 is attached to the other end of the case 11.

A guide shaft 17 is provided protruding from the cap 16, and the guide shaft 17 is loosely inserted into a bottomed hole 18 drilled along the center of the shaft 15, and the outer peripheral surface of the guide shaft 17 and the bottomed hole 18 are connected to each other. A coil spring 19 is interposed between the cap 16 and the bottom surface of the bottomed hole 18 through a gap formed between the cap 16 and the inner peripheral surface.

Insulating substrates e.g. alumina substrates 2 elongated in the axial direction are disposed on the inner peripheral surface of the case 11, for example at the upper and lower parts.
0 and 21 are arranged and fixed, respectively. On these alumina substrates 20 and 21, a first resistance section and a plurality of electrodes connected thereto, and a second resistance section and a plurality of electrodes connected thereto are formed, respectively, as will be described in detail later. There is. And the lead wire 22a,
22b, 22c and 23a, 23b, 23c are soldered to each electrode formed on each alumina substrate 20, 21 through holes 24 and 25 drilled in the cap 16, respectively. It is sealed by.

A brush holder 27 is externally fitted and fixed to the end of the shaft 15 inside the case 11, and is connected to a first sliding resistance part 40 (FIG. 4a) formed in the longitudinal direction on the alumina substrate 20 and parallel thereto. A brush (slider) 28 electrically connected to the provided electrode 44 (FIG. 4a) and slidingly contacted on the upper surface thereof is caulked to the brush holder 27 by a brush holding fitting 29. There is.
Similarly, the second sliding resistance section 50 (FIG. 4a) formed in the longitudinal direction on the alumina substrate 21 and the electrode 53 (FIG. 4a) arranged in parallel thereto are electrically connected. A brush (slider) 30 that slides on the upper surface of these components is caulked to the brush holder 27 by a brush holding fitting 31.

FIG. 4a shows first and second sliding resistors formed on alumina substrates 20 and 21, respectively.

On the right side from the specific position B of the longitudinal first resistor 41 formed on the alumina substrate 20, there is a longitudinal first resistor 41 formed on the alumina substrate 20.
The first sliding resistance section 40 is constituted by the first resistor 41 and the first conductor 42 . Electrodes 43 and 44 made of elongated conductors are formed in parallel at a predetermined interval on both sides of the first sliding resistance section 40 in the width direction.
The electrode 43 and the first conductor 42 are connected at the right end, and the electrode 44, the first resistor 41 and the electrode 43
have lead wires 22a, 22 at their left ends, respectively.
b, and 22c.

A second sliding resistance section 5 formed on the alumina substrate 21 so as to be parallel to the first sliding resistance section 40
0 is the first sliding resistance portion 40 for the specific position B.
A long second resistor 51 is formed on the right side of the specific position B, and a second conductor 52 is connected to the left side so as to be oppositely symmetrical. Electrodes 53 and 54 made of elongated conductors are formed in parallel at a predetermined interval on both sides of the second sliding resistance section 50 in the width direction. The electrode 54 and the second resistor 51 are connected at the right end, and the electrode 53, the second resistor 51 and the electrode 54 are connected to the lead wire 23 at the left end.
a, 23b and 23c.

The sliders 28 and 30 shown in FIG. 2 are arranged between the first resistance section 40 and the electrode 44 and between the second resistance section 50 and the electrode 53 shown in FIG. 4a. .

The longitudinal lengths of the first resistor 41 and the second resistor 51, their respective resistance values, resistance change rates, and other specifications are set according to the intended use of the potentiometer 10. .

Next, the output signal of the potentiometer 10 configured as described above will be explained. Note that for ease of explanation, the first resistor 41 and the second resistor 5 are
1. The length in the longitudinal direction and other specifications of each are the same.

In FIGS. 2 to 4a, the lead wires 22c and 23b of the potentiometer 10 are both grounded, and a predetermined voltage V _B is applied to the lead wires 22b and 23c.

If the sliders 28 and 30 that move together in this state are in sliding contact with the specific position B, the lead wire 22a
The electrode _V1 , which is transmitted through the slider 28 and the electrode 44, becomes the ground potential, and the voltage is transmitted to the lead wire 23a through the slider 30 and the electrode 53.
V ₂ is also at ground potential, that is, zero volts.

When the sliders 28 and 30 slide from the specific position B to the right, the voltage V ₂ changes as shown in Fig. 4b according to the amount of sliding.
On the other hand, the voltage V ₁ increases as shown by the solid line in FIG.
It is maintained at ground potential as shown by the broken line.

When the sliders 28, 30 slide to the left from the specific position B, the voltage _V1 increases from the ground potential in accordance with the amount of this sliding, while the voltage _V2 is maintained at the ground potential.

For this reason, the axis 1 of such a potentiometer 10
5 is connected to a detected object (not shown), a change in the position of the detected object can be detected as a change in voltages V ₁ and V ₂ . If the object to be detected is, for example, a directional valve with a neutral position, the potentiometer 10
When the specific position of the directional control valve is set to the neutral position, the amount of change in the position of the directional control valve from the neutral position can be detected as the amount of voltage change in the voltage V ₁ or V ₂ increasing from the ground potential.
Also, move the potentiometer 10 to position X in FIG. 4b.
When used in the range from
4 or the electrode 53 to which the lead wire 23a is connected.

Furthermore, the output voltage V ₁ of the potentiometer 10
When the two signals V2 and _V2 are input to a control device (not shown) and the control device controls a hydraulic device or the like (not shown) based on these signals, the inside of the potentiometer 10 is Even if an abnormality occurs in the potentiometer 10 due to a short circuit between the electrodes due to adhesion of water droplets, independent signals will be generated on the right and left sides of the neutral position.
Since V ₁ and V ₂ are input, there is no mistake in identifying the right side and the left side. Therefore, safety is improved.

In the above embodiment, since the sliding contact positions of the sliders 28 and 30 that move together are the same, the specific position B of each of the first sliding resistance 40 and the second sliding resistance 50 is Although the explanation has been made assuming the same position, when the first slider slides into contact with a specific position of the first sliding resistance part 40, the second slider slides into a specific position of the second sliding resistance part 50. It is only necessary that they touch, and it is not necessary that both specific positions be at the same position.

(Effects of the invention) As described above, according to the invention, the first sliding resistor is formed by connecting the first resistor and the first conductor, each of which is linear, in series with the first specific position in between. Department and
A second conductor and a second resistor each having a linear shape are connected to a second conductor and a second resistor.
a second sliding resistance section connected in series across a specific position, a first slider slidingly in contact with the first sliding resistance section, and a second sliding resistance section connected in series with a specific position sandwiched therebetween; a second slider in contact with the first slider, the first sliding resistor and the second sliding resistor are arranged such that the second conductor faces the first resistor and The second resistor is mounted inside the cylindrical case so as to face the conductor, and the second resistor is mounted between the two sliding resistors from one end of the case in the longitudinal direction to the other end. A guide shaft is provided in a protruding manner, and one end of the sliding shaft that is slidable along the guide shaft and that engages with the detected object protrudes from the other end of the case in a watertight manner, and the first The first and second sliders are moved around the sliding axis so that the second slider and the second specific position come into sliding contact when the specific position and the first slider come into sliding contact. the first slider and the first
A lead wire that outputs a signal corresponding to the position of sliding contact with the second resistor and a lead wire that outputs a signal corresponding to the position of sliding contact between the second slider and the second resistor are made watertight. Since the potentiometer is configured to extend outside the case, it is possible to store the potentiometer compactly and watertight within the same case, avoiding short-circuiting of the resistor due to water droplets adhering to it as in the past. can do.

Also, the first and second resistors in the case are
As the single sliding shaft moves through the second slider, the resistance value increases and decreases independently of each other, and the two resistance value increases and decreases due to both resistors are always output alternatively. It is possible to simultaneously determine the position and direction of the object to be detected without error, and even if water droplets adhere to the resistor, at least the direction of the object to be detected will not be erroneously determined.

Furthermore, since both sliders of the potentiometer move in a straight line with a specific position in between, it is useful for detecting, for example, the left/right position and neutral position of a directional control valve for hydraulic equipment. In this case, one end of the sliding shaft protrudes outside the cylindrical case, but since the movable part is only near the one end of the sliding shaft, the seal between the inside of the case and the outside is created by the protruding sliding shaft. It only needs to be applied to the surrounding area.

[Brief explanation of the drawing]

Figures 1a and b are circuit configuration diagrams and characteristic diagrams of a conventional potentiometer, Figure 2 is a vertical cross-sectional view of a potentiometer to which an embodiment of the present invention is applied, and Figure 3 is an arrow shown in Figure 2. Line-sectional views and FIGS. 4a and 4b are explanatory diagrams of essential parts and characteristic diagrams of the potentiometer shown in FIG. 2. 10... Potentiometer, 15... Shaft (sliding shaft), 17... Guide shaft, 22a, 23a... Lead wire, 28... First slider, 30... Second slider , 40...first sliding resistance section, 41...first
resistor, 42... first conductor, 50... second sliding resistance section, 51... second resistor, 52... second conductor, B... first and second specific position.

Claims (1)

[Scope of utility model registration request] A first sliding resistance section including a first resistor and a first conductor, each linear, connected in series with a first specific position in between;
a second sliding resistance section formed by connecting resistors in series across a second specific position; a first slider in sliding contact with the first sliding resistance section; a second slider slidingly in contact with the sliding resistance section;
the sliding resistance part and the second sliding resistance part in the first sliding resistance part.
The second conductor faces the resistor, and the second resistor faces the first conductor, respectively, in a cylindrical case, and between the two sliding resistors, A guide shaft is provided protruding from one end of the case in the longitudinal direction to the other end, and one end of the sliding shaft that engages with the detected object is slidable along the guide shaft. the first specific position and the first specific position.
the first and second sliders are attached to the sliding shaft so that the second slider and the second specific position come into sliding contact when sliding in contact with the slider of the first slider; a lead wire that outputs a signal corresponding to a sliding contact position between the slider and the first resistor; and a signal corresponding to a sliding contact position between the second slider and the second resistor. A potentiometer characterized in that lead wires for outputting the power are each extended outside the case in a watertight state.