JPS5914802B2 - oil dump equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is concerned with an oil dump device that can be used for a cassette holder of a cassette tape recorder, etc., and is a device that always slides smoothly at a substantially constant speed even when the ambient temperature changes. The purpose is to provide

The following is an example of the use of oil dump equipment.

The cassette holder of the set tape recorder will be shown and explained. As a cassette holder for a cassette tape recorder.
There is one in which the upper body of the cassette holder is in the form of a door that can be opened and closed.

In this structure, a piston type, windmill type, sliding type, etc. are used as the eject mechanism in order to smoothly open the cassette holder at a constant speed when the eject button is pressed. In the piston type, fluid is filled in a cylinder divided into two chambers by a pair of pistons with a narrow gap, one of the cylinders or pistons is fixed to the main body, and the other piston is connected to a cassette holder. The cassette holder opens smoothly at a constant speed due to the resistance when the fluid passes through the gap between the piston and the cylinder when the cassette holder is opened.

When gas is used as the fluid in this method, at the beginning of the opening operation of the cassette holder, the gas opens rapidly because the gas is compressed, and then after the pressure of the gas becomes constant, it suddenly opens due to the effect of the viscous resistance of the gas. The movement of the cassette holder becomes slow, and the cassette holder opens at two speeds of 15 degrees. When a liquid is used as the fluid, the opening operation of the cassette holder is smoother than when using a gas. However, since pressure is applied to the liquid during operation, the liquid tends to leak into the cylinder, and the leaked volume is replaced with air, which has the disadvantage that the movement gradually becomes two stages. The windmill type converts the spring pressure that opens the cassette holder into rotational force, increases the gear ratio of the gear, and rotates the rotary blades at high speed.

At this time, the opening operation of the cassette holder is performed slowly due to the viscous resistance of the air. However, with this method, the cassette holder opens in stages due to uneven rotational speed of the rotary blades, is weak against large loads, has almost no effect, and has drawbacks such as the rotary blade's 90-turn sound. have The sliding type uses sliding resistance, and an example is shown in Fig. 1.

In FIG. 1, 1 is a cassette holder that can be opened and closed;
A tape cassette 2 can be stored inside. Reference numeral 3 denotes a spring that biases the cassette 35 holder 1 to open in one direction, and is provided between the cassette holder 1 and the chassis 4.

When the cassette holder 1 is closed, it is locked to a hook 5, and when the eject button 6 is pressed to release the hook 5, the tape cassette opening is projected by the biasing force of the spring 3. A fan-shaped drive tooth r is integrally provided at the lower end of the force set holder 1, and the drive tooth T meshes with cylindrical bodies 9 and 10 attached to a mounting board 8 provided on the chassis 11. One of the cylindrical bodies 9 and the other cylindrical body 1
0 is rotatable, and grease is filled between the two cylindrical bodies 9 and 10, and when the force set holder 1 is opened, the rotating shaft 12
The cylindrical body 10 is rotated by the driving teeth 7 which rotate around the cylindrical body 10. Since the cylindrical body 10 rotates slowly due to the effect of the grease, the force set holder 1 opens smoothly. Figures 2A and 2b show details of the oil dump portion in Figure 1.

A pair of metal fixed shafts 9a, 10a are implanted in the chassis 8, and cylindrical tooth bodies 9b, 10b made of polyacetal resin are attached to the fixed shafts 9a, 10a, respectively, with a gap between them. The tooth members 9b and 10b are engaged with each other. Drive teeth r mesh with the gear body 10b. Rings 14 and 14a prevent the gear bodies 9b and 10b from falling off the fixed shafts 9a and 10a.

The gaps between the two gear bodies 9b, 10b and the fixed shafts 9a, 10a are filled with grease 13, 13a. Note that the thickness of this layer of grease 13, 13a is approximately half the thickness of the above-mentioned gap. FIG. 2C shows another embodiment.

A fixed shaft 21 is implanted on the base plate 15, a spacer 18, a washer 19, and a nut 20 are fitted into the fixed shaft 21, and a rotary plate 17 is fitted onto the base plate 15 with a small gap therebetween. Grease 16 is filled between the substrate 15 and the rotating plate 1r. 22 is a connecting rod that connects the force set holder and the rotary plate 1r.

However, such a conventional sliding type has fixed shafts 9a, 1
The gap between Oa and the gear bodies 9b, 10b is neglected, and emphasis is placed only on the material and processing of the gear bodies 9b, 10b.

Therefore, when the ambient temperature changes, the grease 13, 13a
The viscosity of the pressure changer changes greatly, and the opening time of the force set holder changes greatly depending on whether it is cold or loose, which is very inconvenient for the user. The principle of this sliding type can be considered as follows.

Assuming that the grease is a Newtonian fluid, the thickness of the grease layer sandwiched between two planes is h, the viscosity of the grease is η, and the force per unit area required when moving the two planes at a relative speed v is as follows. It is expressed by the formula. Applying this to the cassette eject mechanism shown in Fig. 1, the pressure of the spring 3 is expressed as S
The distance that the gear body 10b moves relative to the fixed shaft 10a when the one-force set holder 1 is changed from the closed state to the open state is t.
Let T be the time required for one opening.

The opening time of the force set holder 1 is therefore inversely proportional to the thickness of the grease layer. The viscosity of grease varies greatly depending on the ambient temperature, and varies by more than an order of magnitude within the normal operating temperature range of approximately 0 to 40°C. Therefore, if the force set holder is designed to open in about 1 second at 0°C, then at 40°C it will be about 0.1
It opens at a speed of less than a second, so it cannot be said that the opening state is smooth.Also, while the fixed shafts 9a and 10a are made of metal, the gear bodies 9b and 10b are made of resin, so the gear body 9b
, 10b has a much larger coefficient of thermal expansion than gear body 9b.
, 10b and the fixed shafts 9a, 10a are wide at high temperatures and narrow at low temperatures, and the frictional forces of the greases 13, 13a are different.

Therefore, if the change due to thermal expansion (contraction) in the gap between the fixed shaft and the gear body designed at 20° C. exceeds 20%, the influence on the opening time of the force set holder becomes significant. FIG. 3 shows the relationship between the opening time of the force set holder shown in FIG. 1 and the ambient temperature.

As shown in the previous equation, the opening time of the force set holder changes depending on the viscosity of the grease, the thickness of the layer, and the contact area, so if these conditions are changed, the characteristic curve will become almost parallel to the characteristic curve in Figure 3. It will be moved. As is clear from this figure, it can be seen that the opening time of the force set holder changes greatly as the ambient temperature changes. FIG. 4 shows the relationship between force set holder formation time, grease thickness, and contact area. This characteristic curve also changes as the conditions change, as in FIG. 3. As is clear from this figure, the narrower the gap between the fixed shaft and the gear body, the longer it takes to open the force set holder, and the wider the opposing area, the longer the opening time. The present invention improves the above conventional drawbacks and provides an oil dump device that always slides at a substantially constant speed even when the ambient temperature changes.One embodiment of the present invention will be described below with reference to the drawings. .

In FIG. 5, reference numeral 26 denotes an elongated sliding device main body having a U-shaped cross section, and a rectangular slider 23 is slidably provided inside this main body.

A pair of opposing side walls 2r, 27a of the sliding device main body
Grease 24, 24a is applied to the inner surface of. The slider 23 slides in contact with the grease 24, 24a on both inner walls. A connecting rod 25 is connected to the force set holder and is fixed to the slider 23.

The slider 23 is made of a material with a large coefficient of thermal expansion (for example, resin), and the slide device main body 26 is made of a material with a coefficient of thermal expansion smaller than that of the slider 23 (for example, metal).

Therefore, at low temperatures, the contraction rate of the slider 23 is greater than the contraction rate of the sliding device main body 26.
, 27a becomes larger to offset the fact that the grease becomes hard at low temperatures.

On the other hand, at high temperatures, the gaps between the slider 23 and both side walls 2r, 2Ta become smaller, offsetting the fact that the grease becomes softer at high temperatures. Therefore, even if the ambient temperature changes, the slider 2
3 slides inside the sliding device body 26 at a substantially constant speed. FIG. 6 shows the relationship between force set holder opening time and temperature when the device of the present invention is applied to a force set holder.

As is clear from this figure, even if the temperature changes greatly, the difference in opening time is small. FIG. 7 shows an example in which the oil dump device of the present invention is applied to a force set holder, in which the force set holder 1 and the connecting rod 25 are connected, the opening operation of the force set holder 1 is transmitted to the slider 23, and the force set holder 1 is This is to keep the opening speed constant. Although the above embodiment has been explained using the force set holder of a force set tape recorder as an example, the present invention is not limited to this in any way, and can be used in various types of equipment that require this type of oil dump device. It goes without saying that there is.

As described above, according to the present invention, in the oil dump device, the slider is made slidable within the slider main body via grease, and the slider is made of a material with a large coefficient of thermal expansion. It is possible to provide a device that can always slide at a substantially constant speed even when the ambient temperature changes greatly.

[Brief explanation of the drawing]

Figure 1 is a side view of the conventional force set holder part, Figure 2A
, b are an enlarged sectional side view and a plan view of the main part of Fig. 1, Fig. 2c is an enlarged sectional side view of the main part of another embodiment shown in Fig. 2a, and Figs. Figure 5 is a cross-sectional side view of an oil dump device according to an embodiment of the present invention, Figure 6 is a diagram showing the characteristics of the same device, and Figure R is a diagram showing the characteristics of the force set holder. FIG. 23...Slider, 24, 24a...Grease, 26...Sliding device main body, 27, 27a
・・・・・・Side wall.

Claims (1)

[Claims] 1. An elongated sliding device main body with a U-shaped cross section, a slider that is slidable within the sliding device main body, and a highly viscous fluid attached between the slider and the sliding device main body. and the slider is made of a material with a coefficient of thermal expansion larger than that of the material of the sliding device main body.