JPH0637730U - Torque sensor - Google Patents

Abstract

(57) [Summary] [Purpose] An object is to provide a torque sensor that can be easily assembled. [Structure] The input shaft 1 is moved to the bearing 35 side along the axial direction of the torsion bar TB, and the input shaft 1 is fixed to the torsion bar TB at the position where the snap ring 32 abuts on the bearing 35. It is possible to position the fifteen and the torque detection section 72 at positions that correctly face each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a torque sensor used in an electric power steering device or the like.

[0002]

[Prior art]

 BACKGROUND ART Conventionally, an electric power steering system detects a torque applied to a steered wheel and controls an electric motor according to the detected torque. A torque sensor for detecting this torque is shown in the schematic view of FIG. The torque detection structure of this torque sensor is such that three detection rings 15a, 15b, 15c are formed on the annular member 15 arranged on the hollow input shaft 1, and the detection rings 15a, 15c have a constant pitch. To form the tooth part. In addition, a torque detecting portion 72 having two coils 72d and 72e is arranged inside the inner wall of the housing G which is the outer periphery of the annular member 15 and faces the detecting rings 15a, 15b and 15c. The coil rings 72a, 72b, 72c are arranged. Further, a tubular member 25 attached to the output shaft 2 is disposed between the detection ring 15a and the coil ring 72a. The tubular member 25 has a tooth portion facing the tooth portion of the detection ring 15a. Form. In the above-described configuration, this torque sensor is configured such that the annular member 15, the tubular member 25 and the torque are generated due to the relative displacement between the input shaft 1 and the output shaft 2 connected via the torsion bar TB. The torque is detected by changing the magnetic characteristics by utilizing the fact that relative displacement is generated between the detection unit 72 and the detection unit 72.

Below the mechanism for detecting the torque described above, an input side tooth portion 11 formed on the input shaft 1 acting as a manual stopper and an output side formed on the output shaft 2 are provided. A tooth portion 21 is provided. As shown in FIG. 2, each tooth of the input side tooth portion 11 is inserted in each tooth of the output side tooth portion 21 with a certain gap therebetween. A stopper detector 71 is fixed to the housing G on the outer circumferences of the input side tooth portion 11 and the output side tooth portion 21. With such a structure, when the input-side tooth portion 11 and the output-side tooth portion 21 come into contact with each other, the magnetic flux emitted from the stopper detection unit 71 is blocked. It is to detect that it has acted as a manual stopper.

[0004]

[Problems to be solved by the device]

 When assembling the above-mentioned torque sensor, it is necessary to assemble the detection rings 15a, 15b, 15c, which are the parts for transmitting the magnetic force, and the coil rings 72a, 72b, 72c, which are correctly arranged in a straight line. In addition, since the input-side tooth portion 11 and the output-side tooth portion 21 are normally required to be in a non-contact state, a constant gap is provided between the bottom surface of the input-side tooth portion 11 and the mounting surface of the output-side tooth portion 21. It is necessary to provide a space α.

In order to assemble the torque sensor while satisfying the above two conditions, the operator inserts the input shaft 1 into the torsion bar TB press-fitted into the output shaft 2, and inserts the input side tooth portion 11 and the output side tooth portion 11. After engaging with the tooth portion 21, the housing G is assembled. At this time, the bottom surface of the input side tooth portion 11 and the top surface of the output side tooth portion 21 are in contact with each other, and the input shaft 1 is movable in the axial direction of the torsion bar TB. In such a state, the operator manually pulls up the input shaft 1 to obtain the desired characteristics while taking the characteristics of the torque sensor, and the detection rings 15a, 15b, 15c and the coil rings 72a, 72b. , 72c are correctly arranged on a straight line. While maintaining this state, the operator forms a through hole in the torsion bar TB and the input shaft 1 and drives the pin 30 to fix the input shaft 1.

The above-described assembly process requires a lot of time for the operator to determine the position of the input shaft 1 while taking the characteristics of the torque sensor, which causes a problem of low productivity. there were. The present invention has been made to solve the above problems, and an object thereof is to provide a torque sensor that can be easily assembled.

[0007]

Means for Solving the Problems The torque sensor of the present invention is, as means for achieving the above-mentioned object, a hollow input shaft rotatably supported by a housing via a first bearing and a second input shaft by a main body. An output shaft that is rotatably supported via a bearing, a torsion bar that is inserted into the input shaft and that connects the input shaft and the output shaft by a coaxial line, and a torsion bar that is provided in the circumferential direction of the input shaft. And a second ring-shaped member provided on the inner wall of the housing facing the teeth of the first ring-shaped member. In a torque sensor that detects a relative displacement as a relative displacement between the first ring-shaped member and the second ring-shaped member to detect torque, the first ring-shaped member and the second ring-shaped member Position facing the ring-shaped member When being positioned, it is characterized in that the positioning member abuts against the second ring-shaped member side of said first bearing mounted on the input shaft.

[0008]

[Action]

 Insert the torsion bar into the hollow part of the input shaft where the first ring-shaped member and the positioning member are installed, with the output shaft with the torsion bar supported on the main body side. On the other hand, it is temporarily assembled. After this, the housing to which the second ring-shaped member and the first bearing are attached is assembled to the main body. In this state, the input shaft is moved to the first bearing side along the axial direction of the torsion bar, and the input shaft is fixed to the torsion bar at the position where the positioning member contacts the first bearing. In this state, the first ring-shaped member is positioned at the correct position facing the second ring-shaped member.

[0009]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same parts as those of the conventional technique will be described using the same reference numerals as those of the conventional technique. FIG. 1 is a view showing a torque sensor of this embodiment, and shows a state after being assembled according to an assembling procedure described later. Reference numeral 1 is an input shaft, and 2 is an output shaft. The input shaft 1 and the output shaft 2 are coaxially connected by a torsion bar TB. The torsion bar TB has one end fixed to the input shaft 1 by a pin 30 and the other end press-fitted to the output shaft 2.

The input shaft 1 is rotatably supported by the housing G through a bearing 35 (first bearing), and the output shaft 2 is rotatably supported by the main body B through a bearing 34 (second bearing). The housing G is assembled with bolts such as the bolt 31. The torque sensor of the present embodiment is used in an electric power steering apparatus, in which an input shaft 1 is connected to a steering shaft, an output shaft 2 is connected to steering wheels, and an output shaft 2 is steered. A gear 33, which transmits the rotational torque from an electric motor (not shown) that generates an assisting force to the output shaft 2, is fixed.

An annular member 15 (first ring-shaped member) is provided at a substantially central portion of the input shaft 1 in the axial direction. Three detection rings 15a, 15b, 15c are formed on the annular member 15, and the detection rings 15a, 15c are formed with teeth at a constant pitch. A torque detector 72 (second ring-shaped member) having two coils 72d and 72e is provided inside the inner wall of the housing G, which is the outer periphery of the annular member 15. The torque detection unit 72 has coil rings 72a, 72b, 72c. The coil rings 72a, 72b, 72c and the detection rings 15a, 15b, 15c face each other in the order of reference numerals and have a predetermined gap. Installed. The tubular member 25 attached to the output shaft 2 is disposed between the detection ring 15a and the coil ring 72a. A tooth portion is formed on the tubular member 25 so as to face the tooth portion of the detection ring 15a.

In the configuration as described above, this torque sensor is configured so that the relative displacement between the input shaft 1 and the output shaft 2 connected via the torsion bar TB causes the teeth of the coil ring 72a to move. By causing relative displacement between the tooth portion of the tubular member 25 facing the tooth portion and detecting the change in the magnetic flux passing between the two tooth portions by the torque detection portion 72, The torque is being detected.

Next, the portion of the manual stopper provided below the annular member 15 will be described. An input side tooth portion 11 is formed at the lower end of the input shaft 1, and an output side tooth portion 21 is formed at the upper end of the output shaft 2. The above-mentioned tubular member 25 is attached to the tip of the output side tooth portion 21. As shown in FIG. 2, each tooth of the input side tooth portion 11 is inserted in each tooth of the output side tooth portion 21 with a certain gap, and the bottom surface of the input side tooth portion 11 and the output side tooth portion A predetermined gap α 2 is provided between the mounting surface 21 and the mounting surface 21. . A stopper detector 71 fixed to the housing G is located on the outer circumference of the input side tooth portion 11 and the output side tooth portion 21. The stopper detecting unit 71 has a coil, and when the input side tooth portion 11 and the output side tooth portion 21 are in contact with each other in a normal state where there is a gap between the input side tooth portion 11 and the output side tooth portion 21. The contact between the input side tooth portion 11 and the output side tooth portion 21 is detected by detecting the change in the magnetic flux between the state in which the input side tooth portion 11 and the output side tooth portion 21 are in contact with each other. It is determined by the characteristics of the stopper detector 71.

A snap ring 32 acting as a positioning member is attached above the annular member 15 of the input shaft 1. The snap ring 32 is in contact with the bottom surface of the bearing 35 when the assembly is completed. Next, the operation of assembling the torque sensor of this embodiment will be described. FIG. 3 is a model diagram showing a procedure for assembling the torque sensor of the present embodiment. At a stage before assembling the housing G to the main body B, the torsion bar TB is press-fitted into the main body B and the output having the gear 33 fixed thereto is output. The shaft 2 is attached. An operator inserts the input shaft 1 with the annular member 15 and the snap ring 32 already attached to the output shaft 2 from above and fits the input side tooth portion 11 and the output side tooth portion 21 together. Tell Then, the tubular member 25 is attached to the output side tooth portion 21. In this state, the bottom surface of the input side tooth portion 11 and the mounting surface of the output side tooth portion 21 are in contact with each other. Further, the input shaft 1 is movable in the axial direction of the torsion bar TB, and no hole for driving the pin 30 for fixing the input shaft 1 and the torsion bar TB is formed (FIG. 3 (a)).

Next, the housing G is attached to the main body B with the bolts 31. At this time, the bearing 35, the torque detecting section 72, and the stopper detecting section 71 are attached to the housing G. Further, in this state, the detection rings 15a, 15b, 15c of the annular member 15 and the coil rings 72a, 72b, 72c of the torque detection unit 72 are displaced from each other in the axial direction of the torsion bar TB (Fig. 3 ( b)).

From the state where the main body B and the housing G are assembled, the operator pulls up the input shaft 1 along the axial direction of the torsion bar TB. At this time, the snap ring 32 fixed to the input shaft 1 contacts the bearing 35, and the amount of pulling up of the input shaft 1 is limited. In this state, the operator makes a through hole in the input shaft 1 and the torsion bar TB, and fixes the input shaft 1 to the torsion bar TB with the pin 30 (FIG. 3 (c)).

In the assembling process described above, the relative positional relationship between the snap ring 32, the annular member 15 and the input side tooth portion 11 on the input shaft 1 is determined by the output ring when the snap ring 32 contacts the bearing 35. 15a, 15b, 15c and the coil rings 72a, 72b, 72c are correctly opposed to each other, and a gap of α is generated between the bottom surface of the input side tooth portion 11 and the mounting surface of the output side tooth portion 21. Therefore, if the input shaft 1 is fixed at the position where the snap ring 32 abuts on the bearing 35 as described above, the assembly is completed, and the stopper detection unit 71 and the torque detection unit 72 provide correct detection values of the characteristics. Obtainable.

Although the snap ring 32 is used as the positioning member for the input shaft 1 in the above-described embodiment, the input shaft 1 may be provided with a positioning projection or the like.

[0019]

[Effect of device]

 As described above, in the torque sensor of the present invention, the input shaft is moved to the first bearing side along the axial direction of the torsion bar, and the input shaft is twisted at the position where the positioning member is in contact with the first bearing. The first ring-shaped member is positioned at the correct position facing the second ring-shaped member only by fixing it to the bar. Therefore, it is possible to provide a torque sensor that is easy to assemble and has few assembly errors. Therefore, the production efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an overall view of a torque sensor of this embodiment.

FIG. 2 is a diagram showing an input side tooth portion 11 and an output side tooth portion 21 of the present embodiment.

FIG. 3 is a diagram for explaining the operation of the present embodiment.

FIG. 4 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 1 Input Shaft 2 Output Shaft 15 Annular Member 72 Torque Detection Part B Main Body G Housing TB Torsion Bar

Claims (1)

[Scope of utility model registration request] 1. A hollow input shaft rotatably supported by a housing through a first bearing, an output shaft rotatably supported by a main body through a second bearing, and inside the input shaft. A torsion bar that is inserted and connects the input shaft and the output shaft with a coaxial line, a first ring-shaped member provided in the circumferential direction of the input shaft, and a tooth portion of the first ring-shaped member. A second ring-shaped member facing each other and provided on the inner wall of the housing, wherein the relative displacement between the input shaft and the output shaft is determined between the first ring-shaped member and the second ring-shaped member. In a torque sensor that detects torque by capturing it as a relative displacement, when the first ring-shaped member and the second ring-shaped member are positioned at positions facing each other, the first ring-shaped member of the first bearing is positioned. Abut on the ring-shaped member side of No. 2 A torque sensor having a positioning member attached to the input shaft.