Acceleration sensor and acceleration sensing system

Claim 2

An acceleration sensor comprising: (a) a housing having an internal space; (b) a body having a receiving space, said body being received in said internal space, and that portion of said internal space other than the portion of said housing occupied by said body serving as an auxiliary receiving space; (c) a tubular bobbin received in said receiving space of said body, said tubular bobbin being fixed at only one of its opposite ends to said body, and the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (d) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (e) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (f) detection means mounted on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (g) a circuit board electrically connected to said detection means, said circuit board being received in said auxiliary receiving space of said housing; wherein said body has a tubular shape, a partition plate being secured to one end of said body, and said partition plate separating said receiving space of said body from said auxiliary receiving space of said housing; wherein the bobbin is positioned in such a manner that one end of said bobbin is disposed close to said auxiliary receiving space of the housing whereas the other end of said bobbin is disposed remote from said auxiliary receiving space; and wherein a rigid resin is filled in said auxiliary receiving space of said housing, and a gel material is filled in said receiving space of said body.

Claim 3

An acceleration sensor comprising: (a) a housing having an internal space; (b) a body having a receiving space, said body being received in said internal space, and that portion of said internal space other than that portion of said housing occupied by said body serving as an auxiliary receiving space; (c) a tubular bobbin received in said receiving space of said body, said tubular bobbin being fixed at only one of its opposite ends to said body, and the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (d) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (e) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (f) detection means mounted on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (g) a circuit board electrically connected to said detection means, said circuit board being received in said auxiliary receiving space of said housing; wherein said body has a tubular shape, a partition plate being secured to the one end of said body, and said partition plate separating said receiving space of said body from said auxiliary receiving space of said housing; wherein the bobbin is positioned in such a manner that one end of said bobbin is disposed close to said auxiliary receiving space of the housing whereas the other end of said bobbin is disposed remote from said auxiliary receiving space; wherein said bobbin has an end wall formed at the one end thereof, a plurality of terminals being formed on said end wall and extending through said partition wall toward said auxiliary receiving space of said housing, and said detection means being electrically connected to said circuit board via said terminals; and wherein a rigid resin is filled in said auxiliary receiving space of said housing, and a gel material is filled in said receiving space of said body.

Claim 4

An acceleration sensor comprising: (a) a housing having an internal space; (b) a body having a receiving space, said body being received in said internal space, and that portion of said internal space other than that portion of said housing occupied by said body serving as an auxiliary receiving space; (c) a tubular bobbin received in said receiving space of said body, said tubular bobbin being fixed at only one of its opposite ends to said body, and the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (d) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (e) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (f) detection means mounted on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (g) a circuit board electrically connected to said detection means, said circuit board being received in said auxiliary receiving space of said housing; wherein said body has a tubular shape, a partition plate being secured to the one end of said body, and said partition plate separating said receiving space of said body from said auxiliary receiving space of said housing; wherein the bobbin is positioned in such a manner that one end of said bobbin is disposed close to said auxiliary receiving space of the housing whereas the other end of said bobbin is disposed remote from said auxiliary receiving space; wherein said bobbin has an end wall formed at the one end thereof, a plurality of terminals being formed on said end wall and extending through said partition wall toward said auxiliary receiving space of said housing, and said detection means being electrically connected to said circuit board via said terminals; and wherein a rigid resin is filled in said auxiliary receiving space of said housing, and a gel material is filled in said receiving space of said body.

Claim 5

An acceleration sensor comprising: (a) a housing having an internal space; (b) a body having a receiving space, said body being received in said internal space, and that portion of said internal space other than that portion of said housing occupied by said body serving as an auxiliary receiving space; (c) a tubular bobbin received in said receiving space of said body, said tubular bobbin being fixed at only one of its opposite ends to said body, and the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (d) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (e) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (f) detection means mounted on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (g) a circuit board electrically connected to said detection means, said circuit board being received in said auxiliary receiving space of said housing; wherein said circuit board has a processing circuit for processing an output of said detection means to produce a detection signal representative of the direction and magnitude of the acceleration, said processing circuit having a temperature compensation circuit for compensating for a variation of the output of said detection means due to a variation of the relative position between said magnet means and said detection means in the direction of the axis of said bobbin, so as to keep said detection signal at a constant level when the acceleration is zero, and said variation of the relative position being caused by a temperature variation; and wherein a rigid resin is filled in said auxiliary receiving space of said housing, and a gel material is filled in said receiving space of said body.

Claim 6

An acceleration sensor comprising: (a) a housing having an internal space; (b) a body having a receiving space, said body being received in said internal space, and that portion of said internal space other than that portion of said housing occupied by said body serving as an auxiliary receiving space; (c) a tubular bobbin received in said receiving space of said body, said tubular bobbin being fixed at only one of its opposite ends to said body, and the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (d) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (e) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (f) detection means mounted on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (g) a circuit board electrically connected to said detection means, said circuit board being received in said auxiliary receiving space of said housing; wherein said circuit board has a processing circuit for processing an output of said detection means to produce a detection signal representative of the direction and magnitude of the acceleration, said processing circuit having a temperature compensation circuit for compensating for a variation of the output of said detection means due to a variation of the relative position between said magnet means and said detection means in the direction of the axis of said bobbin, so as to keep said detection signal at a constant level when the acceleration is zero, and said variation of the relative position being caused by a temperature variation; and wherein a rigid resin is filled in said auxiliary receiving space of said housing, and a gel material is filled in said receiving space of said body.

Claim 7

An acceleration sensor according to claim 3, in which said detection means comprises a differential transformer having a primary coil and a pair of secondary coils, said processing circuit comprising a primary exciting signal-generating circuit for outputting a primary exiting signal of high frequency to said primary coil of said differential transformer, a synchronous rectifying-smoothing circuit for effecting synchronous rectification and smoothing of a differential output of said second coils, and an output circuit for amplifying a voltage difference between a reference voltage and an output of said synchronous rectifying-smoothing circuit and for adding said reference voltage to the amplified voltage difference, and said output circuit having an element for varying said reference voltage in accordance with a temperature variation, so that said output circuit functions as said temperature compensation circuit.

Claim 8

An acceleration sensing system comprising: (a) a body; (b) a tubular bobbin which is fixed at only one of its opposites ends to said body, the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (c) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (d) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (e) detection means received on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (f) a processing circuit for processing an output of said detection means to produce a detection signal representative of the direction and magnitude of the acceleration, said processing circuit having a temperature compensation circuit for compensating for a variation of the output of said detection means due to a variation of the relative position between said magnet means and said detection means in the direction of the axis of said bobbin, so as to keep said detection signal at a constant level when the acceleration is zero, and said variation of the relative position being caused by a temperature variation.

Claim 9

An acceleration sensing system comprising: (a) a body; (b) a tubular bobbin which is fixed at only one of its opposites ends to said body, the other end of said bobbin being movable relative to said body in a direction of the axis of said bobbin; (c) a magnetic member received within said bobbin for movement in the direction of the axis of said bobbin; (d) magnet means for attracting said magnetic member to a reference position within said bobbin, said magnet means being disposed radially outwardly of said bobbin and supported on said body; (e) detection means received on an outer periphery of said bobbin so as to detect a displacement of said magnetic member from said reference position; and (f) a processing circuit for processing an output of said detection means to produce a detection signal representative of the direction and magnitude of the acceleration, said processing circuit having a temperature compensation circuit for compensating for a variation of the output of said detection means due to a variation of the relative position between said magnet means and said detection means in the direction of the axis of said bobbin, so as to keep said detection signal at a constant level when the acceleration is zero, and said variation of the relative position being caused by a temperature variation.