JPH06221870A - Linear resolver - Google Patents

Abstract

PURPOSE:To develop a rotary type resolver into a linear resolver by solving problems on configuration specific to a linear resolver. CONSTITUTION:From a coil 28 wound around the first salient pole the detection signal, wherein detection value changes by 360 deg. each time a slider part moves by pitch p, is obtained. From a coil 29 wound around the second salient pole 23, the detection signal, wherein detection value changes by 360 deg. each time a slider part moves by L/M, is obtained. From a coil 30 wound around the third salient pole 24, the detection signal whose level changes each time a slider part 2 moves by L/(m+1) is obtained, and based on the signal level of the third detection circuit 7, the cycle order of the detection signal of the second detection circuit 6 is detected. Based on the value of the detection signal of the second detection circuit 26, the cycle order of the detection signal of the first detection circuit 5 is detected, and from the detected cycle number and the value of the detection signal of the first detection circuit 5, absolute position of the slider part is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a linear resolver which detects an absolute position in a linear direction.

[0002]

2. Description of the Related Art Conventionally, as a rotary type magnetic resolver, for example, Japanese Patent Application No. 3-16555 filed by the present applicant.
There was one described in the specification of No. 9. This magnetic resolver is a combination of a 1X resolver and an nX resolver. The 1X resolver is a resolver in which the phase of the detection signal is modulated by 360 ° each time the rotor makes one revolution.
The nX resolver is a resolver in which the phase of the detection signal is modulated by 360 ° each time the rotor rotates 1 / n (n is an integer). In such a magnetic resolver, the rotation position is detected with the resolution of 1 / n rotation by the detection signal of the 1X resolver, and the rotation position within the detected 1 / n rotation is detected by the detection signal of the nX resolver, thereby performing an absolute rotation. Detect the position. When this magnetic resolver is expanded to form a linear resolver, the rotor of the magnetic resolver becomes a slider of the linear resolver. However, in the magnetic resolver, the length of the rotor is equal to the length of the stator, whereas in the linear resolver, the length of the slider must be shorter than the length of the stator. Therefore, it is necessary to devise the setting of the slider length.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and solves a structural problem peculiar to a linear resolver and develops a rotary type resolver into a linear resolver. The purpose is to

[0004]

SUMMARY OF THE INVENTION The present invention is a linear resolver for detecting an absolute position in a linear direction, wherein the linear resolver extends in the traveling direction of the slider portion and has teeth formed at a pitch p along the length direction. No. 1 stator core and a second stator core extending in the running direction of the slider portion, the width of which changes by m cycles over the entire length, and a second stator core extending in the running direction of the slider portion, the width of which changes in m + 1 steps over the entire length. And a stator portion having a stator core 3 and a 0 ° salient pole group, a 90 ° salient pole group, a 180 ° salient pole group, and a 270 ° salient pole group, and teeth are formed at a pitch p in each salient pole group. The respective salient pole groups are out of phase with each other by p / 4, and these salient pole groups include a first salient pole facing the first stator core and a 0 ° salient pole group, 90 °. ° salient pole group, 180 ° salient pole group and 270 ° salient pole group The salient pole groups are arranged so as to be offset from each other by p _s / 4 (p _s is the pitch at which the second stator core changes), and these salient pole groups are arranged in a second position facing the second stator core. A salient pole and a third salient pole having teeth facing the third stator core, and a first winding portion wound around each of the first, second and third salient poles. , Second and third coils, excitation means for exciting the first to third coils, and the inductance of the first coil is determined by the positions of the teeth of the first stator core and the teeth of the first salient poles. By utilizing the change according to the phase difference, the inductance of the second coil and the first detection circuit that outputs a detection signal that changes the detection value by 360 ° each time the slider section moves by the pitch p. Depending on the facing area between the second stator core and the second salient pole The second detection that outputs a detection signal in which the detection value changes 360 ° each time the slider portion moves by L / m (L is the total length of the first to third stator cores) Utilizing the fact that the inductance of the circuit and the third coil changes according to the facing area between the third stator core and the third salient pole, each time the slider unit moves by L / (m + 1). A third detection circuit that outputs a detection signal whose signal level changes, and the detection signal of the second detection circuit based on the signal level of the third detection circuit is the detection signal in what cycle. Whether or not the second
Of the detection signal of the first detection circuit on the basis of the value of the detection signal of the detection circuit, and the detected cycle number and the detection signal of the first detection circuit are detected. A linear resolver, comprising: a calculation unit that obtains the absolute position of the slider unit from the value.

[0005]

According to the present invention, three types of stator cores and three types of salient poles facing the stator cores are provided. First
From the coil wound on the salient pole of the
A detection signal in which the detection value changes by 360 ° is obtained each time it moves. From the coil wound around the second salient pole, a detection signal whose detection value changes by 360 ° is obtained every time the slider portion moves by L / m. From the coil wound around the third salient pole, a detection signal whose level changes each time the slider unit moves by L / (m + 1) is obtained. Then, based on the signal level of the third detection circuit, it is detected in what cycle the detection signal of the second detection circuit is. Furthermore, the second
Of the detection signal of the first detection circuit based on the value of the detection signal of the detection circuit, the detected cycle number and the value of the detection signal of the first detection circuit are detected. The absolute position of the slider is calculated from

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
2 is a block diagram showing an embodiment of the present invention. FIG. 1 is a diagram showing a configuration of a stator portion, and FIG. 2 is a diagram showing a configuration of a slider portion. In these figures, (a) is a plan view and (b) is a side view.

In FIG. 1, reference numeral 1 is a stator portion. In the stator portion 1, 11 is a stator plate, and 12 to 14 are stator cores fixed to the stator plate 11. The stator core 12 extends in the traveling direction (cc 'direction) of the slider portion and has teeth formed at a pitch p along the length direction. The stator core 13 also extends in the traveling direction of the slider portion, and the width thereof changes in a sinusoidal shape for four cycles over the entire length. The stator core 14 also extends in the traveling direction of the slider portion, and the width changes in five steps over the entire length.

In FIG. 2, reference numeral 2 is a slider portion. In the slider portion 2, 21 is a slider plate, and 22 to 24 are salient poles provided on the slider plate 21. The salient poles 22 are 0 ° salient pole group 22 ₁ , 90 ° salient pole group 22 ₂ , and 180 ° salient pole group 22 _3.
And a 270 ° salient pole group 22 ₄ . Each salient pole group is formed with three teeth 25 at a pitch p. Further, the phases of the teeth 25 of each salient pole group are shifted by p / 4. These salient pole groups face the stator core 12. No salient pole 23
° salient pole group 23 ₁ , 90 ° salient pole group 23 ₂ , 180 ° salient pole group 2
3 ₃ and 270 ° salient pole group 23 ₄ . Two teeth 26 are formed in each salient pole group. These four salient pole groups are arranged within the slider long pitch p _s . The salient pole groups are arranged at positions shifted by p _s / 4. here,
The slider long pitch p _s is the period of a sine wave that represents the change in the width of the stator core 13. Moreover, each salient pole group faces the stator core 13. The salient pole 24 has a stator core 1
Teeth 27 facing the 4 are formed. 28, 29, 3
Reference numeral 0 is a coil wound around salient poles 22, 23 and 24, respectively.

Reference numeral 4 is an exciting means for exciting the coils 28 to 30, reference numerals 5, 6 and 7 are detection circuits for performing position detection based on the induced voltages of the coils 28, 29 and 30, respectively, and reference numeral 8 is a detection circuit 5 to 7. This is a calculation unit that obtains the absolute position of the slider unit based on the detection signal.

Here, for example, when the pitch p of the stator core 12 is 3 mm and the number of teeth n is 100, the total length L of the stator core 12 is 3 mm × 100 = 300 mm. The slider long pitch p _s is 300 mm / 4 = 75 mm

The operation of the linear resolver thus configured will be described. First, the operation of the detection circuit 5 will be described. FIG. 3 is a diagram showing a specific configuration of the excitation means 4 and the detection circuit 5 of FIG. In FIG. 3, L ₀ , L ₉₀ , L ₁₈₀ , and L ₂₇₀ are wound around a 0 ° salient pole group 22 ₁ , a 90 ° salient pole group 22 ₂ , a 180 ° salient pole group 22 ₃ , and a 270 ° salient pole group 22 ₄ , respectively. It is a coil that has been burned. L ₀ , L ₉₀ , L ₁₈₀ , and L ₂₇₀ are a 0 ° phase coil, a 90 ° phase coil, a 180 ° phase coil, and a 270 ° phase coil, respectively. 0 ° salient pole group 22 ₁ , 90 ° salient pole group 22 ₂ , 1
Since 80 ° stator teeth 22 _3, 270 ° stator teeth 22 ₄ the formed teeth phases are shifted by p / 4, 0 ° phase coils,
90 ° phase coil, 180 ° phase coil, 270 ° phase inductance L ₀ of the _{coil, L 9 0, L 180,} L 270 is respectively given by the following equation. L ₀ = L ₁ (1 + msin θ) L ₉₀ = L ₁ {1 + msin (θ + 90 °)} = L ₁ (1 + mcos θ) L ₁₈₀ = L ₁ {1 + msin (θ + 180 °)} = L ₁ (1-msin θ) L ₂₇₀ = L ₁ {1 + msin (θ + 270 °)} = L ₁ (1-mcos θ) L ₁ , m; constant, θ: phase difference between teeth of stator core 12 and 0 ° salient pole group 22 ₁ tooth Excitation means 4 is 0 ° phase coil L ₀ and 180 ° phase coil L ₁₈₀
Is excited with an AC voltage of Ecos ωt (E: amplitude of voltage, ω: angular velocity, t: time). Also, 90 ° phase coil L
_{The 90} and 270 ° phase coil L ₂₇₀ is excited with an AC voltage of Esin ωt. Voltages V _{1 to} V ₄ given by the following equations are applied to the detection resistor R connected to the coils of each phase by such excitation.
Occurs. _{V 1 = K (1 + msinθ} ) cosωt V 2 = K (1-msinθ) cosωt V 3 = K (1 + mcosθ) sinωt V 4 = K (1-mcosθ) sinωt K: constant amplifier A1~A3 for V ₁ ~V ₄ The calculation shown in the following equation is performed. V = V ₁ −V ₂ + V ₃ −V ₄ = 2 mK (cosωt sin θ + sin ωt cos θ) = 2 mK sin (ωt + θ) = 2 mK cos (ωt + θ−90 °) The signal V thus obtained is the low-pass filter 51.
The low frequency component is extracted by and the waveform is shaped by the comparator 52. Further, the excitation signal Ecos generated by the excitation means 4
The waveform of ωt is also shaped by the comparator 53. The phase difference counter 54 measures the phase difference θ−90 ° between the phase modulation signal from the comparator 52 and the reference signal from the comparator 53 which is not phase modulated. By this, the pitch p
The phase difference within is detected.

Next, the operation of the detection circuit 6 will be described. 0 °
Salient pole group 23 ₁ , 90 ° salient pole group 23 ₂ , 180 ° salient pole group 23
Position of the ₃ and 270 ° stator teeth 23 ₄ are shifted by p _s / 4. As a result, the 0 ° salient pole group 23 ₁ , the 90 ° salient pole group 23 ₂ , the 180 ° salient pole group 23 ₃ and the 270 ° salient pole group 23 ₄
And the facing areas S ₁ , S ₂ , S ₃ , and S ₄ of the stator core 13 are given by the following equations. _{S 1 = S 0 + ΔSsinθ 1} S 2 = S 0 + ΔSsin (θ 1 + 90 °) = S 0 + ΔScosθ 1 S 3 = S 0 + ΔSsin (θ 1 + 180 °) = S 0 -ΔSsinθ 1 S 4 = S 0 + ΔSsin (θ ₁ + 270 °) = S ₀ −ΔS cos θ ₁ θ ₁ : Phase with pitch p _s of 360 ° Since the inductance of the coil wound around each salient pole group is proportional to the facing area of the stator core and salient pole, Group 2
The inductance of each coil wound on 3 ₁ to 23 ₄ is also expressed by the formula (1). The detection circuit 6 has the same configuration as the detection circuit 5 and performs detection in the same manner as the detection circuit 5. As a result, the slider portion 2 within the pitch p _s
Is detected.

Next, the operation of the detection circuit 7 will be described. Since the width of the stator core 14 changes in 5 steps every L / 5,
The inductance of the coil 30 changes in five steps every time the slider unit 2 moves L / 5. The detection circuit 7 detects the induced voltage of the coil 30. Therefore, the level of the detection signal of the detection circuit 7 changes in five steps as the slider unit 2 moves. As a result, the position of the slider portion 2 is detected with L / 5 as the resolution. At this time, E from the excitation circuit 4
The coil 30 is excited by using one of the signals of cos ωt and Esin ωt. This is because the detection circuit 7 only needs to detect the signal level.

The absolute position is detected as follows. Figure 4
Is a graph showing changes in the detection signal of the detection circuit,
(A), (b), (c) are detection circuits 5, 6, 7 respectively.
The change of the detection signal of is shown. As shown in FIG. 4, the detection value of the detection signal of the detection circuit 5 changes 360 ° each time the slider portion moves by the pitch p. The detection value of the detection signal of the detection circuit 6 is 36 each time the slider portion moves by L / 4.
Change by 0 °. The detection signal of the detection circuit 7 is L when the slider section is L.
The level changes every time you move by / 5. The calculation unit 8
Based on the signal level of the detection circuit 7, it is detected in what cycle the detection signal of the detection circuit 6 is a detection signal.
Further, based on the value of the detection signal of the detection circuit 6, the detection circuit 5
Of the detection signal is detected, and the absolute position of the slider portion is obtained from the detected cycle number and the value of the detection signal of the detection circuit 5. In this way, the absolute position is detected.

Although the width of the stator core 13 changes over four cycles and the width of the stator core 14 changes over five steps in the embodiment, the present invention is not limited to this value. Generally, the stator core 1
When the width of 3 changes over m periods (m is an integer), the width of the stator core 14 changes in m + 1 steps.

[0016]

According to the present invention, three types of stator cores and salient poles are provided in the stator portion and the slider portion, respectively, and the absolute positions are detected by properly using these. As a result, the length of the slider section can be made shorter than the length of the stator section, the structural problems peculiar to the linear resolver can be solved, and a rotary type resolver can be expanded into a linear resolver. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

FIG. 3 is a diagram showing a specific configuration example of a detection circuit.

FIG. 4 is a waveform diagram of a detection signal of the detection circuit.

[Explanation of symbols]

1 stator 12-14 stator core 2 slider section 22-24 poles 22 ₁ to 22 _4, 23 ₁ to 23 ₄ stator teeth 25-27 teeth 28-30 the coil 4 exciting means 5-7 detecting circuit 8 arithmetic unit

Claims (1)

[Claims] 1. A linear resolver for detecting an absolute position in a linear direction, comprising: a first stator core extending in a traveling direction of a slider portion and having teeth formed at a pitch p along a length direction; A stator having a second stator core extending in the traveling direction and having a width that changes by m cycles over the entire length, and a third stator core extending in the traveling direction of the slider portion and having a width that changes in m + 1 steps over the entire length. Section, 0 ° salient pole group, 90 ° salient pole group, 180 ° salient pole group and 270
° Each salient pole group has teeth formed at a pitch p, and each salient pole group has a tooth phase difference of p / 4. A first salient pole facing the stator core, a 0 ° salient pole group, a 90 ° salient pole group, a 180 ° salient pole group and 270
° It consists of salient pole groups, each salient pole group is p _S / 4 (p _S is the second
The stator cores are arranged at different pitches, and these salient pole groups are formed with second salient poles facing the second stator core and teeth facing the third stator core. Third
A salient pole having a salient pole, first, second and third coils respectively wound around the first, second and third salient poles, and exciting the first to third coils. And the inductance of the first coil changes in accordance with the phase difference between the teeth of the first stator core and the teeth of the first salient poles to move the slider portion by the pitch p. And the inductance of the second coil changes in accordance with the facing area between the second stator core and the second salient pole. Utilizing this, the detected value is 3 every time the slider portion moves by L / m (L is the total length of the first to third stator cores).
By utilizing a second detection circuit that outputs a detection signal that changes by 60 °, and that the inductance of the third coil changes according to the facing area between the third stator core and the third salient pole, A third output of a detection signal whose signal level changes each time the slider unit moves by L / (m + 1)
Of the detection circuit and the third detection circuit, the detection signal of the second detection circuit is detected based on the signal level of the third detection circuit, and the second detection circuit is further detected. Of the detection signal of the first detection circuit based on the value of the detection signal of the first detection circuit, and the slider is detected from the detected cycle number and the value of the detection signal of the first detection circuit. A linear resolver, comprising: a calculation unit for obtaining an absolute position of the unit.