JPS6126817A - Transducer for measuring torque and/or speed of shaft - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a magnetic transducer that senses changes in magnetic permeability of a rotating shaft to determine the speed and torque of the rotating shaft.
Regarding.

Encircling the rotating shaft, having primary and secondary windings, creating an alternating magnetic field adjacent to and within the shaft and measuring changes in this field to determine various shaft values such as speed, torque, and horsepower. essentially a transformer to obtain information about the properties of
Devices have been developed that have magnetic transducers that act as magnetic transducers.

When a driven or loaded shaft is subjected to torsional stress, compression and tension occur in various parts of the shaft, which changes the magnetic permeability of the shaft and thus changes the pattern of magnetic flux in the shaft, changing the magnetic field. known to change. A torque information signal can be created from this altered or resulting magnetic field. Such a detection device is disclosed in U.S. Pat. No. 4,100,794, issued July 18, 1978, in the name of Nidwin, J. Meixner. Additionally, in the Makesner patent it is recognized that the magnetic field also varies as a function of shaft speed due to amateur reactions in the shaft. Eddy currents flow along the surface of the rotating shaft, creating a countermagnetic field that opposes and distorts the initial magnetic field. As the rotational speed increases, the flow of eddy currents increases and the amount of distortion of the magnetic field also increases. As a result, this modified magnetic field can also be utilized to generate a velocity information signal.

The required alternating magnetic field is described in Meixner's U.S. Patent No. 4.
, 100,794, by means of a primary or excitation magnetic assembly that surrounds an axis of rotation and includes a circular magnetic core having a series of radially inwardly extending poles whose free ends are in close contact with the axis. It will be done.

A primary winding containing a corresponding series of series-connected winding coils is wound on the magnetic core, each coil being positioned on a respective radial pole to align the axis of the winding of each #@ wire. is done perpendicular to the axis. an alternating current voltage source is connected to the multiple coil primary windings to apply an alternating current to the windings to generate an alternating magnetic flux adjacent to and within the shaft;
This causes the magnetic field generated in the primary winding to be perpendicular to the axis. According to the Makesner patent, the bidirectional current flow within the primary winding required to provide the necessary alternating current excitation may also be achieved by converting direct current to alternating current by means of a Bridge-type inverter or similar switching device. It can be caused by U.S. Patent No. 4,100
, 794, a pair of secondary or pick-up magnetic assemblies of similar construction to the primary assembly respond to the resulting magnetic fields modified by the torque and velocity characteristics of the shaft to generate these sensed magnetic fields. It provides information signals that indicate characteristics.

An improved excitation system for the transducer was developed by George
U.S. Patent No. 4,10 issued August 15, 1978 in the name of Etsch Stasotman and assigned to the Assignee.
No. 6,334. In the detection device shown in the Shuxotman patent, the other multiple coil primary winding is wound on the primary magnetic assembly in a two-wound arrangement. Each radial pole has another coil wound thereon consisting of one coil from each of the other primary windings. The other coils on each pole are physically adjacent to each other, but electrically isolated from each other. In such a drive method, bidirectional current flow is not necessary and a simple switching circuit can be used to alternately supply DC current pulses from a DC voltage source to the other primary winding. , when a pulse of DC is applied to one primary winding, the other primary winding is deactivated and all the poles are magnetized to one polarity; When the next winding is applied, the first winding is deactivated and all the poles are magnetized with opposite polarity.As a result, the DC pulses are passed through the alternating flux, or the alternating magnetic field, by the axis of rotation. It is generated in the central part of the magnetic core.

A similar transducer with a different output signal processing circuit was published by Nidwin J. Meixner 19
No. 4.3Q6,462, issued Dec. 22, 1981, and assigned to the assignee of the present invention.

The magnetic transducer of the present invention is disclosed in U.S. Pat. No. 4,100,794, U.S. Pat. No. 4,106,334 and U.S. Pat.
It can be replaced in place of the transducer used in the detection device disclosed in No. 462. The transducer of the present invention is significantly smaller, requires much less space, is significantly lighter, requires fewer windings, can be manufactured with stamped parts, and has a much more efficient magnetic The use of materials provides substantial improvements and advantageous advances over the transducers of the above-mentioned patents. Furthermore, the transducer of the present invention is similar to the conventional transducer.
This allows for flexibility in design that would not otherwise be possible. For example, multiple poles can be used if desired.

As another example, the number of poles is not determined by the number of winding coils, but the number of coils is independent of the number of poles.

The present invention provides a transducer for sensing a predetermined characteristic, such as torque or speed of a rotating shaft, that is a function of and modified by the sensed characteristic. It includes a primary magnetic assembly having a primary winding energized by an applied excitation signal to create an alternating magnetic field near and within the shaft. The transducer further includes first and second magnetic secondary windings for producing a signal responsive to the modified magnetic field to provide an information signal indicative of the properties of the sensed axis. Contains assembly. According to the invention, each magnetic assembly includes a hollow ring-shaped magnetic shell surrounding and coaxial with the axis of rotation;
The other sides of the shell are closed and joined at the radially outermost rim of the shell, and these other sides are separated and joined at the radially innermost rim of the shell. It is open at the rim so that the shell has a U-shaped cross section. At least one winding is disposed within the magnetic shell, the plane defined by the turns of each winding being perpendicular to the axis of the rotational shaft. Each magnetic assembly also includes a number of relatively short poles extending radially inwardly from the innermost rim on each side of the shell;
The free ends of these poles are close enough to the shaft that a magnetic circuit is formed through both the shell and the shaft.

The features of the invention that are considered novel are particularly defined in the claims. The invention, however, is best understood by reference to the following description in conjunction with the accompanying drawings in which like reference numerals indicate like parts.

FIG. 1 now shows the transducer 10 of the present invention disposed about a rotating shaft 11 whose torque and speed are to be sensed. The device driving the shaft and the load driven by the shaft are not shown. This is because it is not important to understanding the invention. For example, a transducer can sense the torque and speed of any one of the vehicle's drive elements, as taught by the aforementioned US patents. Thus, to sense driveline torque and speed, the transducer 10 extends from the transmission housing and is attached to a portion of the output shaft that is typically connected to a universal joint that provides torque to the vehicle's drive wheels. I can do it.

As disclosed in the above-mentioned U.S. patents, transducer 10 includes three basic elements, a primary or excitation magnetic assembly 14 and a pair of secondary or pink-up magnetic assemblies 15 and 1G. , magnetic assembly 14 is mounted between magnetic assemblies 15 and 16. These three assemblies I4.15 and 16 can be held together by suitable devices such as screws. Such attachments are not shown in the drawings to simplify the drawings. Since assembly 15 is in front of transducer 10, it will be referred to below as the front secondary magnetic assembly, and assembly 16 will be referred to as the rear secondary magnetic assembly. As will become apparent from the following description, the primary assembly 14 is arranged adjacent to and within the portion of the shaft 11 extending through the transducer 10 for creating the required alternating magnetic field. at least one 1 for producing an alternating current excitation effect of
Including the next winding. Also, as will become apparent below, each secondary assembly 15 and 16 includes a pair of secondary windings that provide output information signals related to the speed and torque characteristics of the rotating shaft 11.

The energization or drive circuitry of primary assembly 14 and the signal processing output circuitry of secondary assemblies 15 and 16 are described in detail in the aforementioned U.S. patents, and such circuitry has been shown here to avoid obscuring the drawings.・Illustrations are omitted here. Accordingly, reference may be made to these patents for an understanding of the manner in which transducer 10 is incorporated into an overall sensing system for generating speed and torque indicating signals. These patents also suggest various ways to utilize the information found by the detection device. For example, the speed indicating signal can be used in an odometer or odometer. On the other hand, the torque indication signal can be used to control gear ratio switching in automatic transmissions. The connection from the drive circuit to the primary winding device is made via cable 17, and the connection from the secondary winding is via cables 18 and 19.
carried out by. Although cable 17 is shown as a single conductor pair, three separate conductors are of course required when the other double-wound primary winding is used.

Now, to describe the detailed structure of the transducer 10, in the drawings, the respective assemblies 14, 15 and 1 are shown.
It can be seen that 6 has basically the same structure. Considering first the primary magnetic assembly 14, this primary magnetic assembly 14 is shown in FIG.

This assembly 14 includes a magnetic shell formed by the other parts 21 and 22 and shaped like a hollow ring or body of revolution, which shell surrounds the axis of rotation 11 and is coaxial with this axis. and the other side of the shell (numerals 21a and 2
2a) are closed and joined at the radially outermost rim of the shell by annular flange portions 21b and 22b of portions 21 and 22, respectively, while the other side is separated. and the shell is open at the radially innermost rim of the shell formed by circular edges 21c and 22c, so that the shell parts 21 and 22 have a U-shaped cross section. It looks like this. More particularly, the shell is formed by two annularly shaped rings 21, 22 having an L-shaped cross section, one ring (21) intersecting the other ring (22).
It is designed to fit inside and be held.

The assembled rings have a U-shaped cross-section, with the outermost rim forming the closed part of the U-shape and the innermost rim of the shell forming the opening of the U-shape. .

Extending radially inwardly from the innermost rim of each side of the shell ring portions 21 and 22 are a number of relatively short poles equally spaced about the rim; The free ends of these poles are brought into close contact with the rotating shaft 11.

More specifically, poles 21d and 21e are 180°
spaced apart from side 21a of shell 21.22, and poles 22d and 22e also spaced 180° and extending radially inwardly from side 22a of the shell 11. It is placed in close proximity to the It is noted that the poles on one side are oriented angularly offset relative to the poles on the other side, such that each pole on each side is aligned with the other pole on the opposite side. In other words, they are arranged at the center between the two, that is, shifted by 90°. This is best illustrated in FIG.

The poles 21d, 21e, 22d, and 22e are located on the side 2
As well as extending radially inwardly from 1a and 22a, these poles also have free ends of all four poles effectively aligned along the same circumference of the axis of rotation in the same plane. It is shaped like this. As mentioned above, the free ends of these poles are arcuately shaped to form an arcuate or curved surface that matches the curvature around the axis. As can be seen, it is important that the curved surfaces of the free ends of these poles be as close as practical about the circumference of the shaft 11 to permit the passage of magnetic flux through the shaft.

Although only one pole is disclosed extending from each side of the shell 21,22, any number of poles, even or odd, can be provided.

At least one primary winding 25 is arranged in the magnetic shell 21.22 in connection with the energizing circuit to which the cable 17 is connected, the winding of each winding wrapping around the shell axis. This causes the plane defined by each winding to be perpendicular to the axis of the shaft. Of course, the wound coil 25 can include a large number of individual winding turns so that a substantially large magnetic field is created. An insulating material 26 is wrapped around the winding 25. Due to this arrangement, when the winding 25 is excited with alternating current, an alternating magnetic field or alternating magnetic flux is generated around the winding, and the shell 21
．． Since 22 is made of magnetic material, most of this magnetic field is effectively constrained by the shell and poles 21d, 21e, 22 and 22e and the magnetic circuit is
It comes to include the part. In this way, magnetic flux is passed from the pole on one side of the shell through a portion of and near the shaft 11 and then to the pole on the other side of the shell. Without these poles, the shell 21.2
2 resembles a series of U-shaped horseshoe magnets arranged in an annular manner, the center or common part of the horseshoe magnets forming the outermost rims 21b, 22b of the shell, and freeing the horseshoe magnets. The ends form circular edges 21c and 22c, and the magnetic flux is simply allowed to pass between these edges.

However, because the poles are provided in this way, the magnetic circuit is controlled so that most of the magnetic flux passes through the shaft 11 from one circular edge to the other.

More specifically, when the primary winding 25 creates an alternating magnetic field, the poles alternate between north and south polarity, such that when poles 22d and 22e are of south polarity, poles 21d and 21e are of north polarity; 22d and 22e
When the poles 21d and 21e have the north polarity, the poles 21d and 21e have the south polarity.

For example, when poles 21d and 21e are of north polarity, magnetic flux is passed from these poles circumferentially around a portion of axis 11 to poles 22d and 22e, which now have south polarity.

Thus, the axial magnetic field is first bent radially by the pole and then circumferentially by the shaft. An alternating magnetic field passing circumferentially through and in the vicinity of shaft 11 is passed through cables 18 and 19 into the secondary windings of secondary magnetic assemblies 15 and 16 as described in the previously mentioned US Pat. is large enough to induce a signal that is applied to and processed by the circuit described in .

The magnetic field generated in the vicinity of and within the shaft 11 is a function of, and is modified by, the rotational speed of the shaft II and the torque applied to the shaft.

In other words, the alternating magnetic flux produced by the excitation of the primary winding 25 is varied as the shaft speed and/or torsional stress within the shaft changes. The modified magnetic field thus obtained induces a signal in the big amplifier or secondary winding, which provides a signal containing information regarding the torque and speed characteristics of the shaft 11. These information signals are processed by the circuitry described in the aforementioned US patents to provide visual indications of shaft speed and torque, for example.

Secondary magnetic assemblies 15 and 16 are clearly similar to primary assembly 1.
4, so only one of the secondary assemblies will be briefly described.

Of course, the physical dimensions of primary assembly 14 are larger than the dimensions of assemblies 15 and 16, as clearly seen in the drawings. This is usually desirable so that the alternating magnetic field produced by the primary assembly is adequate to induce the necessary information signals in the other secondary winding.

Turning now to the front secondary assembly 15 shown in FIG.
8.29, these rings 28.29 having an L-shaped cross-section, such that the rings 28 are fitted and retained within the rings 29. It turns out that there is. These combined shell parts 28, 29 have other sides 28a and 29a, which sides have annular flange parts 28b and 29.
b is closed and joined at the radially outermost rim of the shell. These other sides 28a and 2
9a is open at the radially innermost rim of the shell bounded by circular edges 28C and 29c.

A pair of short poles 28d and 28e extend radially inwardly from the innermost rim of side 28a and along axis 11, and a pair of short poles 29d and 29e extend along axis 11 from side 29a. 11 and extends along this,
The curved free ends of these poles fit around and close enough to the shaft 11 that a magnetic circuit is formed through both the shell and the shaft. The poles are shaped so that their curved surfaces are all aligned along the same circumference of the axis 11. As with the primary assembly 14, the other poles on each side of the shell 28, 29 are spaced apart by 180°, with the poles on one side relative to the poles on the other side. Each pole on each side is oriented so that it is centered between the other adjacent poles on the opposite side, or spaced 90 degrees from the poles. This is best illustrated in Figure 6. One secondary winding 31, around which a layer 32 of insulating material is wound, is arranged in the magnetic shell 28, 29, the turns of the winding surrounding the shaft 11, in this way each winding The plane of the rotating portion is perpendicular to the axis of the shaft 11.

What is noted in FIG. 6 is that the secondary assemblies 15 and 1
6 corresponding poles are aligned with each other. On the other hand, in the preferred embodiment, the poles of the primary assembly 14 are angularly offset relative to the poles of the secondary assembly, such that each primary pole is aligned with two adjacent pairs of aligned poles. It is placed centrally between the secondary poles.

Although each of these three shells is formed from components of the other, it can be seen that each shell can be formed as a single unit. Of course, it is easier to insert the winding inside the shell if the shell is formed from two parts.

Although not shown in the drawings, non-magnetic conductive spacers, such as aluminum spacers, can be used to minimize direct connections between the primary and secondary windings.

Preferably, the signal induced in the secondary winding is uniquely determined by the magnetic field available in the shaft, modified by the speed and torque characteristics of the shaft.

The present invention thus provides a significantly simpler and cheaper construction than conventional transducers which require relatively long radial poles and a significant number of windings, and which require individual wound coils for each pole. It turns out that. The dimensions of the transducer of the present invention, particularly its diameter, are significantly smaller than conventional transducers, and its weight is also much smaller. Furthermore, substantially less magnetic material is required. Furthermore, the transducer of the present invention
The magnetic shell can be easily manufactured by stamping. Furthermore, the number of poles used is also freely selectable, and this number is independent of the number of winding coils, which must be at least three, with one primary winding and the other two
All that is needed is the next winding.

While particular embodiments of the invention have been described and illustrated above, modifications thereof are possible and the invention as limited by the claims may include all that come within the true spirit and scope of the invention. It is intended to include modifications.

[Brief explanation of drawings]

FIG. 1 shows a transducer having primary and secondary magnetic assemblies constructed in accordance with the present invention fitted around a rotating shaft to measure torque and speed characteristics of the rotating shaft. FIG. 2 is a partially cutaway perspective view showing an embodiment. FIG. 2 is a plan view of the transducer shown partially cut away along line 2--2 of FIG. . FIG. 3 shows the primary or excitation magnetic assembly sandwiched between the other secondary or big amp magnetic assembly.
3 is a partial cross-sectional view of the transducer taken along line 3--3 of the figure; FIG. FIG. 4 is an exploded perspective view, partially cut away, of the primary magnetic assembly. FIG. 5 is an exploded perspective view, partially cut away, of the front secondary magnetic assembly. FIG. 6 is a plan view showing each of the three magnetic assemblies, with the left and right assemblies showing the front and rear secondary assemblies, respectively, and the primary assembly shown in the center. 10...Transducer-11...
...Rotating shaft 14...Primary magnetic assembly 15.16...Secondary magnetic assembly 17.18.19...Cable 21.22...Shell Body parts 21a, 22a...Side parts 21b, 22b...Flange parts 21c, 22c...Circular edge 21d121e...Pole 22d, 22e...Pole 22d, 22e...Pole 25. ......Primary winding 26...Insulating material 28.29...Shell body parts 28a, 29a...Side parts 28b, 29b...Flange part 28c , 29c...Circular edge 28d128e...Pole 29d, 29e--Po/l/ 31...Secondary winding 32...Insulating material patent applicant Porg Warner Corporation

Claims (9)

[Claims] (1) for sensing a predetermined characteristic of a rotational axis (11), generating an alternating magnetic field in the vicinity of said axis that is a function of the sensed characteristic of this axis and modified by said sensed characteristic; and a primary magnetic assembly (14) having a primary winding (25) energized by an excitation signal applied therein, further comprising an information signal indicative of a characteristic of said sensed axis. a secondary winding (3) for producing a signal responsive to said modified magnetic field to produce a
1) having first and second secondary magnetic assemblies (15,
16), each of said magnetic assemblies comprising a hollow ring-shaped magnetic shell (21, 22) surrounding and coaxial with said shaft, the two sides of said shell (2
1a, 22a) is the radially outermost rim (21
b, 22b) are joined and closed,
These two sides are separated and the shell is open at the radially innermost rim (21c, 22c), so that said shell has a U-shaped cross section. The hollow ring-shaped magnetic shell (21, 22
), and at least one winding (2) disposed within the magnetic shell.
5), the at least one winding (25) in which a plane defined by the winding portion of each winding is perpendicular to the axis of the rotating shaft; and the outermost part of each side of the shell. A number of relatively short poles (21d, 2) extend radially inwardly from the inner rim.
1e, 22d, 22e), the free ends of these poles being arranged close enough together that a magnetic circuit is formed through both the shell and the shaft. Paul (21d, 21e, 22d, 22e)
A transducer comprising: (2) The predetermined characteristic of the shaft is the torque of the rotating shaft, and the AC magnetic field is changed as the torsional stress in the shaft changes. A transducer according to scope 1. (3) The primary magnetic assembly comprises two primary windings (25) in the shell wound in a two-turn arrangement. transducer. (4) The transducer according to claim 1, wherein the free end of each of the poles is shaped into an arc, forming a curved surface that matches the curvature of the rotation axis. (5) The transformer according to claim 1, wherein the free ends of the poles are shaped into an arc shape and are aligned along the same circumference of the rotating shaft in the same plane. Ducer. (6) The shell body is formed by two parts (21, 22), one part (21) including the other side part. transducer. (7) The shell has an L-shaped cross section and is attached in two annular shapes dimensioned so that one ring (21) fits and is retained within the other ring (22). formed by shaped rings (21, 22), such that the combined ring has a U-shaped cross section and the outermost rim (
21b, 22b) form a closed part of the U-shape, and the innermost rims (21c, 22b) of the shell form a closed part of the U-shape.
Transducer according to claim 1, characterized in that 1c) forms the U-shaped opening. (8) each side of said shell has the same number of poles equally spaced around the innermost rim, the poles (21d, 21e) of one side being the same as the poles (21d, 21e) of the other side; Paul (
22d, 22e) such that each pole on each side is centered between two adjacent poles on the opposite side. A transducer according to claim 1, characterized in that: (9) Each side of said shell has two poles spaced 180° around the innermost rim, the poles (21d, 21e) on one side being on the other side; are oriented angularly offset with respect to the poles (22d, 22e), such that each pole on each side is in the middle of the two poles on the opposite side and thus 90° from these poles. The transducer according to claim 1, characterized in that the transducer is arranged at intervals of .