JPH04301574A - Rotary sensor - Google Patents

Abstract

PURPOSE:To dispense with a specific structure for application of a preload on the bearing of a magnetic drum. CONSTITUTION:A magnetic drum 1, a magnetism detecting element 7 and a housing 8 accommodating these components inside are prepared. Besides, a support member 4 to which the magnetism detecting element 7 is fixed is disposed with interposition of a bearing 5 which bears a fixed shaft 2 provided above the main body of a motor. Moreover, inside the housing 8, for instance, a spring 10 is fitted between the end part of this housing 8 and the support member 4. Since the spring 10 is used also as a damper spring and thereby a preload can be applied to the bearing, any specific structure is dispensed with.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

[Field of Industrial Application] The present invention relates to a rotation sensor used to detect the rotational speed and rotational position of a rotating body such as the output shaft of various engines or the rotating shaft of various motors, and in particular to a preload spring for a bearing. The present invention relates to a rotation sensor including a member.

0002

[Prior Art] When detecting the rotational speed or rotational position of a rotating body, for example, changes in magnetism are detected by a magnetic detection element such as an MR element or a Hall element, and then converted into an electrical signal and output. ing.

FIG. 8 shows such a detection principle.
At least one pair of magnetic poles N and S are arranged on the outer peripheral surface of a cylindrical rotating body, such as a magnetic drum 1, and a magnetic detection element 7 is arranged with a predetermined gap G between the magnetic pole surface and the magnetic pole surface. The rotating shaft 2 of the magnetic drum 1 is connected to a rotating shaft of a motor (not shown), etc., and when the magnetic drum 1 starts rotating, magnetic poles N and S are connected.
The magnetism generated from the magnetic field changes.

This change in magnetism is detected by the magnetic detection element 7, which converts it into an electrical signal and outputs a substantially sinusoidal signal as shown in FIG. This output signal is subjected to signal processing, and based on this, the rotational speed and rotational position of the motor are detected. The conventional magnetic rotation sensor that detects magnetic changes in this manner has a structure in which the rotating shaft of the magnetic drum is supported by two bearings. When the rotating shaft is supported through a bearing in this way, it is necessary to apply preload to the bearing. Conventionally, preload is applied by two bearings and a spring provided between them.

[0005]

However, conventional rotation sensors have a problem in that they require a special structure to apply preload to the bearing.

The present invention has been made in response to the above-mentioned problems, and it is an object of the present invention to provide a magnetic encoder unit that can apply preload without requiring any special structure.

[Configuration of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a cylindrical rotating body attached to a rotating shaft of a rotation source, and a surface of the rotating body facing the rotating body through a predetermined gap. and a detection element that detects the rotation amount of the rotation body and outputs an electric signal corresponding to the rotation amount, the rotation sensor is arranged via a bearing that receives a rotation shaft coupled to the rotation source of the rotation body, and The present invention is characterized by comprising a detection element support member that fixes the detection element in position, and a spring member that applies preload to the bearing whose one end is attached to the detection element support member.

[0009]

[Operation] A detection element support member with a detection element fixed at a predetermined position so as to face the surface of the rotating body is arranged via a bearing that receives a rotating shaft provided, for example, at a position opposite to the rotation source of the rotating body. do. Further, one end of a spring member used as a damper spring member is attached to the support member. As a result, the damper spring member can also be used as a preload applying spring member, so that no special structure is required for applying preload.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a first embodiment of the rotation sensor of the present invention, and its cross section is shown in FIGS. 2 and 3. 1 is a magnetic drum with at least one pair of magnetic poles N and S arranged on its outer peripheral surface 1A as shown in FIG.
The rotating shaft 2 is coupled to the rotating shaft of the motor body 3. Reference numeral 4 denotes a plate-shaped support member, which is disposed above the motor body 3 via a bearing 5 consisting of a ball bearing that receives the rotary shaft 2 .

Reference numeral 7 denotes a magnetic detection element such as an MR element or a Hall element, and as shown in FIG. They are fixed so that they are facing each other. A housing 8 houses the magnetic drum 1 and the magnetic detection element 7 therein. This housing 8 has fixing screws 11
It is fixed to the motor main body 3 at a plurality of locations. The magnetic drum 1, rotating shaft 2, support member 4, magnetic detection element 7, housing 8, etc. constitute a unit 9 that constitutes a magnetic drum mounting structure.

10 is a spring as shown in FIG.
One end is attached to the support member 4 and the other end is attached to the housing 8 by the fixing screw 11. That is, the spring 10 is installed inside the unit 9. This spring 10 is used to apply a preload to the damper spring/bearing 5, and the supporting member 4
It acts to apply preload to the bearing 5 so as to lift or lower it.

Next, the operation of this embodiment will be explained.

As shown in FIG. 4, when a spring 10 having a larger height L than that shown in FIG. It acts to apply preload to the bearing 5 which is provided above the motor body 3 and which receives the rotating shaft 2.

On the other hand, when a spring 10 having a smaller height L than that shown in FIG. 2 is attached to the housing 8 as shown in FIG. By working, it acts to apply pressurization to the bearing 5.

By combining the spring 10 with the bearing 5 in this manner, it is possible to apply a preload to the bearing.

Further, according to this embodiment, when the magnetic drum 1 starts rotating, the upper surface of the magnetic drum 1 can continue rotating without touching the support member 4 due to the presence of the spring 10.

FIG. 6 shows a second embodiment of the present invention, in which a spring 10 is attached to the outside of the unit 9. One end of the spring 10 is directly attached to the support member 4 and the other end to the motor body 3 by a fixing screw 11. The support member 4 also includes one bearing 5 for receiving the rotating shaft 2 provided above the motor body 3.
is located through.

Similar effects can be obtained in the second embodiment as well, as in the first embodiment, by comparing the axial height dimension of the spring 10 with the rotating shaft 2.

FIG. 7 shows a third embodiment of the present invention, in which reference numeral 1 denotes a magnetic drum with at least one pair of magnetic poles N and S arranged on its outer peripheral surface 1A as shown in FIG. ,
The rotating shaft 2 is connected to the rotating shaft of the motor main body 3 so that rotational force is transmitted thereto. Reference numeral 4 denotes a plate-shaped support member, which is disposed above the motor body 3 via two bearings 5 and 6 that receive the rotating shaft 2. The support member 4 is positioned at a desired position facing the magnetic pole surface of the magnetic drum 1. The magnetic detection element 7 is fixed via the intermediate member 12 so as to be arranged. A housing 8 houses the magnetic drum 1 and the magnetic detection element 7 therein. The magnetic drum 1, rotating shaft 2, support member 4, magnetic detection element 7, housing 8, etc. constitute a unit 9 that constitutes a magnetic drum mounting structure.

[0022] According to such a third embodiment, the second
Similar effects can be obtained according to the embodiment.

Although each embodiment has been described using a magnetic drum as a rotating body, the rotating body is not limited to a magnetic drum.

[0024]

As described above, according to the present invention, the spring that acts as a damper spring is used as it is to apply preload to the bearing, so preload can be applied without the need for a special structure. be able to.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a first embodiment of a rotation sensor of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is a sectional view illustrating the operation of this embodiment.

FIG. 5 is a sectional view illustrating the operation of this embodiment.

FIG. 6 is a sectional view showing a second embodiment of the invention.

FIG. 7 is a sectional view showing a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of the principle of magnetic detection.

FIG. 9 is a signal waveform diagram output from a magnetic detection element.

[Explanation of symbols]

1 Magnetic drum 2 Rotation axis 4 Magnetic detection element support member 5 Bearing 7 Magnetic detection element 8 Housing 9 units 10 Spring

Claims (3)

[Claims] Claim 1: A cylindrical rotating body attached to the rotating shaft of a rotation source, and a rotating body arranged opposite to the surface of the rotating body through a predetermined gap to detect the amount of rotation and output an electric signal in accordance with the rotation amount. a detection element support member disposed via a bearing for receiving a rotation shaft coupled to the rotation source of the rotating body and fixing the detection element at a predetermined position; A rotation sensor comprising: a spring member that applies preload to the bearing whose one end is attached to the detection element support member. 2. The rotation sensor according to claim 1, wherein the rotation axis of the rotor is provided at a position opposite to the rotation source. 3. The rotation sensor according to claim 1, wherein the rotation axis of the rotor is provided on the same side as the rotation source.