JPH0244171Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotary encoder that is directly connected to a rotary drive source, and its purpose is to provide an apparatus equipped with a coupling mechanism that performs heat insulation and heat radiation functions.

Figure 1 is a sectional view of the main parts showing an example of a conventional configuration.
2 is a rotating shaft to which a coupling boss 4 to which an encoder plate 3 is fixed is fitted; 5 is a mounting plate; 6 is a cover; and 7 and 7' are opposed to each other. It is a detection sensor arranged.

In FIG. 1, an encoder plate 3 is attached to a coupling boss 4 between detection sensors 7 and 7'.
are arranged vertically, and these detection sensors 7,
7' is attached to the vertical plane P of the rotary drive source 1 by means of a mounting plate 5 via a mounting seat 8 and a cover 6. More specifically, in such a device, the coupling boss 4 is fitted onto the rotating shaft 2 and then fixed, the encoder plate 3 is assembled, and the mounting plate 5
is fixed, and the detection sensors 7, 7' are positioned and arranged in the slit detection portion of the encoder plate 3, and are integrated.

Such a rotary encoder is directly connected to the rotary drive source 1 when applied to, for example, a high-speed drawing device.
A material with low inertia is preferred.
On the other hand, the rotary drive source 1 has become more compact due to improvements in insulation technology, and it is now possible to use F-class insulation or higher as a general-purpose product. As a result, when high-acceleration drawing is desired for the above-mentioned application, it is preferable to use a rotary encoder connected to the rotary drive source 1 with F-class insulation or higher. However, in the structure of the conventional device as shown in FIG. 1, the encoder plate 3 is usually made of plastic and deforms when exposed to high temperatures.
For example, this will affect the measurement of the slit portion. If this material is made of a heat-resistant material such as glass, problems such as cracking in the fixed part of the encoder plate 3 may occur due to the difference in thermal expansion coefficient between the coupling boss 4 and the metal material. Become. Further, as the radiant heat and conductive heat from the rotary drive source 1 are transmitted to the fixed portion of the encoder, the heat exceeds the amount of heat radiated from the surface of the cover 6, for example, and the temperature rises. For this reason, as a method of suppressing the detection sensors 7, 7' within the allowable operating temperature, it is attempted to provide a margin in the rotational drive source 1 or to reduce the operating conditions. Of course, if the encoder body is separated by a coupling or the like, a heat insulating effect can be obtained, but this is not suitable for high-acceleration rotation or for improving accuracy.

The present invention was developed in view of the above-mentioned points, and in particular, in order to provide heat insulation to the rotating parts, the coupling bosses are brought into contact with each other in an edge-like manner, and grooves are provided in the circumferential direction of the contact surface, thereby creating an exceptional design. This realizes a device with a coupling function. The present invention will be explained below with reference to the drawings.

2 to 4 show an embodiment according to the present invention, and FIGS. 2a and 2b are sectional views of main parts in FIG. Figures 3 and 4 are cross-sections of Figure 2, respectively.
B is an explanatory diagram of a cross section. In the figure, the same reference numerals as in FIG. 1 indicate parts having the same function.

In FIGS. 2 to 4, 9 is a heat shield plate, 10 is a spacer, 11 is a tightening metal fitting, M is a groove appropriately provided on the circumferential side of the coupling boss 4', and A is a heat shield plate 9 and a mounting plate 5'. This shows the air layer that forms between the two. That is, in the configuration of this embodiment, the coupling boss 4' has an edge shape at both end sides in the axial direction at the portion that contacts the rotating shaft 2, and a groove M is provided in the circumferential direction of the shaft to prevent rotation. It is fitted onto the shaft 2. The encoder plate 3 is attached to this coupling boss 4', and the detection sensors 7, 7' are disposed on the mounting plate 5' via the mounting seat 8' and the cover 6' in the fixed part as shown in Fig. 1. is the same as Further, the mounting plate 5' is installed on the vertical plane P of the rotary drive source 1 via a heat shield plate 9 for shielding the encoder fixing portion from heat and a spacer 10 for maintaining the air space A.

Next, we will consider the heat transfer behavior according to this embodiment by dividing it into a rotating part and a fixed part. That is, the heat from the rotating shaft 2 is transmitted to the rotating part through the abutting surface of the coupling boss 4', but since this abutting surface is extremely small in both the axial and circumferential directions as shown in the example, the amount of heat transferred is small. It is possible to prevent heat from being dissipated without being accumulated and causing an unreasonable increase. This will be explained in further detail with reference to FIG. 2b.

Since we are only concerned with preventing heat transfer from the rotating shaft 2, if the wall thickness W of the edge portion of the coupling boss 4' is ideally straight and extremely thin, the drive will occur as the rotating shaft 2 rotates. This results in a large deflection due to various vibrations on the source side and the encoder side. In particular, axial deflection vibration causes contact between the encoder plate 3 and the detection sensors 7, 7', causing a fatal problem of erroneous measurements.

Therefore, if this wall thickness W is made into a straight shape with the required rigidity, the amount of heat transferred from the contact surface with the rotating shaft 2 will increase in proportion to the increase in the wall thickness W, and the Since it receives radiant heat from the rotating shaft 2 and convection heat from the air, it cannot provide effective heat insulation.

Here, since the thickness W shape of the contact part with the rotating shaft 2 is made into an edge shape as shown in FIG. 2b,
It has suitable rigidity and can obtain extremely high heat insulation and heat dissipation.

That is, the moment M received by the wall thickness W when the axial force Zp is applied is zero at the contact point N and reaches a maximum (M=MAX) at the root. For the sake of explanation, this can be simply assumed to be flat (M=
Zp・H).

Therefore, even if the thickness is made thinner at the N point, the rigidity is hardly impaired, and by adding thickness toward the root according to the distance from the contact surface, it is possible to maintain both rigidity and heat insulation effects. becomes possible. In other words, since the contact portion with the rotating shaft 2 has an edge shape and is in line contact with the wall thickness W, the amount of heat transfer is extremely small. Furthermore, the area near the shaft surface receives high radiant heat HT ₁ and air convection heat HT ₂ , but since the area near the shaft surface is thin and edge-shaped, there is little heat conduction surface, so the amount of heat received is straight as described above. In addition, the edge-shaped oblique surface H ₁ has a larger surface roughness than the vertical surface H in the straight case, so that more heat can be radiated.

In this way, it is clear that the coupling boss 4' contributes to the heat insulation of the encoder plate 3 and provides many heat insulation effects without impairing rigidity.

Further, the fixing part has a structure in which radiant heat is shielded by the heat shield plate 9, and furthermore, an air layer A is provided by the spacer 10, so that almost no heat transfer occurs. In this way, the amount of heat input to the encoder can be made very small, and the amount of heat dissipated can be made almost equal.
Since the temperature rise can be suppressed to a small level, the encoder plate portion and the detection sensor portion can be used under normal environmental conditions. This allows the encoder to be designed to the extreme with reduced weight and inertia.

As explained above, according to the present invention, it is possible to provide a device with an adiabatic coupling function that allows the encoder to be used under normal environmental conditions.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of main parts showing a conventional configuration example;
Figures a and b are explanatory diagrams of a main part cross section and a coupling part showing one embodiment of the present invention, and Figures 3 and 4 are partial explanatory diagrams showing cross sections A and B of Figure 2, respectively. 2...Rotating shaft, 3...Encoder plate, 4,
4'...Coupling boss, 7,7'...detection sensor, 9...heat shield, 10...spacer.

Claims (1)

[Scope of utility model registration request] A rotary type characterized in that a coupling boss fitted to a rotating shaft protruding from a rotational drive source is brought into edge-like contact at both ends in the axial direction, and an encoder plate is attached to the coupling boss. encoder.