JPH0579403U - Lever type dial gauge - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a lever type dial gauge that detects a displacement with high accuracy and obtains an electrical output without being affected by the mechanical accuracy of a sensor and the winding state of a coil. [Structure] The parallel magnetic field generation units 10 and 1 are provided on the other end side of a detection lever 3 whose one end is in contact with an object to be measured and which swings around a fulcrum 2.
1 is fixed, the magnetic detection sensor 12 is externally fixed in the parallel magnetic field, and the displacement of the parallel magnetic field due to the displacement of the object to be measured is detected by the magnetic detection sensor. Thereby, the displacement can be detected with high accuracy and an electric output can be obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lever type dial gauge for measuring a precision error of a machined surface by a machine tool and a minute roughness of the surface of various objects.

[0002]

[Prior Art]

 Conventionally, a lever type dial gauge has been used to measure the micro-roughness of the surface of various objects. This dial gauge presses one end of a probe that swings around a fulcrum against the object to be measured, expands the displacement on the other end using various gears such as racks and pinions, and measures minute lengths by rotating the pointer. It is a thing.

On the other hand, the mechanical dial gauge is inconvenient because the user has to detect the measured value by looking at the scale and perform various processing and work corresponding to it. Therefore, it has been proposed to convert the displacement caused by the lever into an electrical change and output the electrical change.One of them is to move the core that makes the enlarged displacement back and forth in the coil forming the differential transformer. There are also those that obtain the detection output.

[0004]

[Problems to be solved by the device]

 Among the above conventional lever type dial gauges, the pure mechanical type using various gears is not only inconvenient for human eyes, but also the angle conversion by the rack and pinion for the direct displacement to be measured. As a result, there was an error due to the gear pitch difference, and there was a limit in terms of accuracy.

Further, in the case of using a differential transformer, in order to improve the accuracy, it is necessary to wind the transformer coil as close as possible to improve the inductance, but the coil is tightly wound. This caused distortion in the winding, and there was a limit to the improvement of the instance, and thus there was a limit to the improvement of the accuracy.

In addition, since the tip of the probe moves in an arc during measurement and the core in the differential transformer also moves in an arc, the clearance between the core and the coil must be set relatively large. However, when the adjustment is difficult and the amount of change in the angle of the circular arc movement becomes large, the moving amount of the tracing stylus and the electric signal output do not have a one-to-one correspondence, and the measuring range becomes narrow.

Therefore, an object of the present invention is to provide a lever type dial gauge that detects a displacement with high accuracy and obtains an electrical output without being affected by the mechanical accuracy of a sensor or the winding state of a coil. To do.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned drawbacks of the conventional device, the present invention fixes the parallel magnetic field generating portion to the other end side of the detection lever, which has one end abutting against the object to be measured and swings around the fulcrum, A lever type dial gauge is configured so that the magnetic detection sensor is fixed to the outside from the outside and the displacement of the parallel magnetic field due to the displacement of the measured object is detected by the magnetic detection sensor. It is designed so that an electrical output can be obtained.

[0009]

[Action]

 Since the present invention is configured as described above, one end of the detection lever abuts the object to be measured, and the detection lever swings around the fulcrum depending on the state of the object to be measured, and the other end side of the detection lever The parallel magnetic field generator provided at the position oscillates. As a result, the magnetic detection sensor fixed from the outside in the parallel magnetic field detects the change in the magnetic amount to the magnetic detection sensor that changes according to the change in the angle of the parallel magnetic field. Detect and get electrical output.

[0010]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, a detection lever 3 is provided in the case 1 so as to be swingable around a support shaft 2 supported by the case 1, and one end of the detection lever 3 protruding from the case 1 is provided. The detection lever 3 is provided with a plug 4, and a support plate 5 is formed on the other end side of the detection lever 3.

A U-shaped yoke 6 is fixed on the support plate 5, and the first magnet 10 and the second magnet 11 are respectively faced inwardly to the standing pieces 7 and 8 of the yoke 6. It is fixed. The first magnet 10 has an N pole on the side facing the second magnet and an S pole on the other side, and the second magnet 11 has an S pole on the side facing the first magnet and an N pole on the other side. And As a result, the opposing surfaces of both magnets become the N pole and the S pole, a parallel magnetic field is generated between both poles, and the poles on the other surface side are connected by the yoke 6.

A magnetic detection sensor 12 fixed to the case 1 is arranged between the facing surfaces of the first magnet 10 and the second magnet 11. The magnetic detection sensor 12 is composed of a first coil 14 wound around one side of a square-shaped core 13 and a second coil 15 wound around an opposite side thereof, and each coil is a saturable coil. In addition, the winding directions of the first coil 14 and the second coil 15 are reversed, and the magnetic fields are reversed by energizing each coil, so that the magnetic field circulates in the core. The orientation of the central core of each coil is arranged and fixed so as to be perpendicular to the parallel magnetic field when the magnetic sensor 12 is initially set (zero output). Further, as shown in FIG. 3, the direction of the central core of each coil may be arranged so as to be parallel to the parallel magnetic field.

An arc-shaped rack 16 is formed at the end of the detection lever 3, a pinion 17 engaging with the rack 16 is rotated to rotate a pointer 18, and its position can be read on a scale 19. It acts as a mechanical dial gauge and is also used for zero point adjustment of the magnetic detection sensor 12.

The first coil 14 and the second coil 15 are connected to the circuit shown in FIG. That is, based on the output from the pulse oscillator 20, the first coil 14 and the second coil 15 are substantially magnetically saturated in the opposite directions by the pulse current supplied from the transformer 21. When a DC magnetic field is applied, the inductance of one coil (for example, the first coil 14) increases and the inductance of the other coil (and thus the second coil 15) decreases. The pulsed voltage supplied to the anode side of the diodes 22 and 22 changes according to the change in the inductance, and the rectified voltage generated in the output resistors 23 and 23 also changes according to the change. Since the changes in the rectified voltage occur in opposite directions, the difference between the two rectified voltages becomes the output of the detection circuit 24. Therefore, as shown in FIG. 5, this output is set to linearly increase up to a magnetic field of ± 50 gauss to obtain an output of ± 6V. The change (s in θ) of the parallel magnetic field given to the magnetic detection sensor is detected by utilizing the portion of this detection characteristic having good linearity. It should be noted that, in a magnetic field higher than that, the characteristic is that the voltage gradually saturates and a voltage of approximately ± 9 V is output in a magnetic field of ± 100 gauss.

As shown in FIG. 6, the BH characteristic when the coil having such a circuit structure is wound around the core made of permalloy has a good linearity in the unsaturated region and a flat saturated portion, It has the characteristics of small hysteresis and very good temperature characteristics. When this permalloy core is constantly saturated by high-frequency excitation, the amount of change in magnetic flux density inside the core changes linearly in proportion to the external magnetic field.

FIG. 6 shows the direction and magnitude of the exciting magnetic field of the coil when there is no external magnetic field, and how the magnetic flux density of the core changes at this time. The magnetic flux density of the core changes from 0 to the saturated magnetic flux density Bs by excitation.

FIG. 7 shows a state when an external magnetic field is applied, and the magnetic flux density of the core changes from Bex to Bs. The coil wound around the core is used for excitation, and at the same time, the change in its inertia is used for detecting the external magnetic field. Since the inductance of the coil is proportional to the change in magnetic flux per unit time, it can be seen that the inductance of the coil changes in proportion to the magnetic flux density of the core having a constant cross-sectional area and the external magnetic field. Moreover, the inductance increases when the direction of excitation of the core and the direction of the external magnetic field are the same, and decreases when they are opposite.

Based on such a principle, it is composed of a detection coil section in which a permalloy core is wound, an oscillation circuit section for exciting the core, and a detection rectification circuit section, and the coil and the detection rectification circuit are both It consists of two groups and works differentially.

As described above, the core is excellent in temperature stability, and the circuit portion is also extremely stable because a completely symmetrical circuit is differentially used. Further, as shown in FIG. 4, a coil and a resistor are connected in cascade, and a pulse voltage having a constant peak value and a constant peak value is applied in one direction to both ends thereof. This causes the pulsed current supplied to the coil to magnetically saturate the core. The voltage generated in the resistor connected to the coil is a pulse voltage for excitation divided by the coil inductance and resistance, and is converted to a DC voltage by the detection rectification circuit.

When using the above device, as shown in FIG. 8, a saw-type displacement detection sensor 31 is fixed by a milling machine 30, a probe 32 thereof is brought into contact with a work 33, and zero adjustment is performed by a dial gauge portion 34. .. As the cutting by the milling machine progresses, the detection lever 3 swings around the support shaft 2 depending on the accuracy and roughness of the cut surface.

The swing angle of the probe 32 portion is the same as the angle change of the parallel magnetic flux with respect to the magnetic detection sensor 12. That is, as shown in FIGS. 9 and 10, the signal detected by the magnetic detection sensor in the parallel magnetic field between the first magnet and the second magnet is detected and rectified by the circuit shown in FIG. (E) becomes E = αH sin θ. Here, θ is an angle with the magnetic field, that is, a displacement angle with respect to the fulcrum of the lever, α is a proportional constant, and H is a Gaussian amount of the parallel magnetic field and is constant. Further, the moving distance (L) of the measuring portion at the tip of the lever is L = asin θ. Here, a is the distance between the measuring part of the lever type dial gauge and the fulcrum. Taking the ratio of the above two equations, E / L = αH sin θ / asin θ = α H / a, and the sensor output E becomes E = L (α H / a). Since (αH / a) is a proportional constant, if this is set to γ, then E = Lγ, and the output (E) is in direct proportion to the moving distance (L) of the measuring part at the lever tip.

This output is subjected to signal processing by the circuit shown in FIG. 4 in the circuit box 9 provided in the sensor body, and sent to the amplifier box 35 as an analog signal. The signal from the amplifier box 35 is displayed on a liquid crystal display unit 36 having a built-in display CPU and is also sent to a transmitter 37 to be wirelessly sent to various control devices such as a milling machine control device 38.

In the above embodiment, it can be used for various machine tools in addition to being used as a milling machine. In addition to machine tools, like the conventional dial gauge, the outer diameter, inner diameter, groove width, Naturally, it is possible to measure the surface roughness and the like, and it can also be used for measuring the eccentricity of the rotating body, the waveform of the vibrating body and the like. The same effect can be obtained by using another magnetic element such as a Hall element or a magnetoresistive element as the magnetic detection sensor.

[0024]

[Effect of the device]

 Since the present invention is configured and operates as described above, no gear is used, no mechanical error occurs, and winding distortion that occurs when a differential transformer is used does not occur. Moreover, it is not necessary to adjust the clearance between the core and the coil. In addition, since the angle change due to the partial circular arc movement of the tracing stylus directly changes the angle of the parallel magnetic flux, there is a proportional relationship between the moving amount of the tracing stylus and the electrical signal output, which results in a clearance similar to when using a differential transformer. A precise sensor can be obtained without any change. Further, it has excellent temperature characteristics and can be used in a wide range of applications, and its output can be transmitted to various control devices to enable accurate control of various devices.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of an essential part of an embodiment of the present invention.

FIG. 3 is a perspective view of a main part of another embodiment of the present invention.

FIG. 4 is a circuit diagram of an embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the external magnetic field of the magnetic sensor and the output voltage.

FIG. 6 is a graph showing the direction and magnitude of the exciting magnetic field when there is no external magnetic field, and the change in the core magnetic flux density at this time.

FIG. 7 is the same graph when an external magnetic field is applied.

FIG. 8 is a system configuration diagram when the sensor of the present invention is used in a milling machine.

FIG. 9 is a schematic view of a lever dial gauge of the present invention.

FIG. 10 is a schematic diagram when the measuring unit of the lever type dial gauge of the present invention is displaced.

[Explanation of symbols]

 1 Case 2 Spindle 3 Detection Lever 4 Probe 5 Support Plate 6 Yoke 9 Circuit Board 10 First Magnet 11 Second Magnet 12 Magnetic Detection Sensor 13 Core 14 First Coil 15 Second Coil 16 Rack 17 Pinion 18 Pointer 19 Scale 20 Pulse Oscillator 21 transformer 22 diode 23 output resistance 24 detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayuki Nakanishi Sakai 535 Sasaki Co., Ltd. Sayama, Sayama City, Saitama Prefecture (72) Creator Shigejiro Shimizu Shigejiro Shimizu 7-32-6 Tokyo Kamata Co., Ltd. In-house

Claims (1)

[Scope of utility model registration request] 1. A parallel magnetic field generator is fixed to the other end of a detection lever, one end of which abuts against an object to be measured and which swings about a fulcrum, and a magnetic detection sensor is externally fixed in the parallel magnetic field.
A lever type dial gauge, wherein the displacement of the parallel magnetic field due to the displacement of the object to be measured is detected by the magnetic detection sensor.