JPH022509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cam drive device that uses the rotational force of a motor to switch operating modes in devices such as magnetic recording and reproducing devices.

Conventional configurations and their problems In recent years, magnetic recording and reproducing devices that use the rotational force of a motor to perform various operations without directly using the operator's hand power have become popular, and small and compact devices have become popular. There are also remarkable trends in energy saving and energy saving. Among these, a method has been proposed in which a cam gear having a toothless portion is used to utilize the rotational force of a motor, and a small force of a drive trigger of the cam gear is used as an operation.

An example of a cam drive device proposed by the present applicant prior to the present application will be described below.

1 to 3 are plan views of the cam drive device during operation, and numeral 1 denotes a drive gear which is directly decelerated by the motor and constantly rotates. 2 is a cam gear located in a position where it meshes with the drive gear, and has several missing teeth. In FIG. 1, one of the two missing teeth faces the drive gear 1. Although not shown, there is a cam surface on the back surface of the cam gear 2, and when the rotational force of the drive gear 1 is transmitted to the cam gear 2, power can be extracted from this cam surface. Also,,
The cam gear 2 has an engaging portion 2a, and when the toothless portion is in a position facing the drive gear 1, the cam gear 2 is urged counterclockwise by a biasing spring 3.

Reference numeral 4 denotes a control rod, which is guided by a shaft 6 mounted on a mechanical chassis and stabilized by the biasing force of a spring 5. This control rod 4 is slid by an operating force such as an operating button or an electromagnet. An engaging protrusion 4a provided at one end of the control rod 4 can engage with protrusions 2b and 2c of the cam gear 2, and the engaging protrusion 4a and the protrusion 2b in FIG. The engagement protrusion 4a and the protrusion 2c are engaged.

The operation of the cam drive device configured as described above will be explained below.

First, from the state shown in Figure 1, connect the control rod 4 to the spring 5.
When it is slid against the urging force of , it moves to the state shown in FIG. In other words, the engaging protrusion 4a of the control rod 4
and the protrusion 2b of the cam gear 2 are disengaged, and the biasing force of the biasing spring 3 causes the drive gear 1 and the cam gear 2 to
interlock. As shown in Fig. 2, the drive gear 1
While the rotational force is being transmitted from the cam gear 2 to the cam gear 2, the cam surface provided on the back uses the power to move other mechanisms.

In the state shown in FIG. 3, the toothless portions of the drive gear 1 and the cam gear 2 face each other again, the engagement protrusion 4a of the control rod 4 engages with the protrusion 2c of the cam gear 2, and the cam gear 2 is stopped. When the control rod 4 is returned from this state, the engagement protrusion 4a of the control rod 4 and the protrusion 2c of the cam gear 2 are disengaged again.
The rotational force of the drive gear 1 is transmitted to the cam gear 2, and the cam surface performs work. Then, the state returns to the state shown in Fig. 1, and the cam gear 1 corresponds to the reciprocating position of the control rod.
is locked at the missing tooth position and the operation is repeated.

Figure 4 schematically shows only the cam gear in the above-mentioned cam drive device.For simplicity, the total number of teeth is 19, there are two missing teeth, and the number of missing teeth is 3 each. It is written as a real gear with 13 teeth, and a missing tooth part is provided at almost the opposite position. As shown in this figure, when the total number of teeth is an odd number, it is not possible to provide a missing tooth at the 180° position, and the missing tooth is at least half a tooth away.For example, the most common cam gear When extracting driving force from the cam surface every 180 degrees, designing the cam surface becomes extremely difficult. Also, the number of teeth on the two gear parts is 7 and 6.
The energy taken out on the cam surface is determined by the number of teeth on the smaller gear part, so in order to take out the specified energy, it is necessary to have a large diameter (number of teeth).
The disadvantage was that this required a number of gears, which deteriorated operating conditions such as motor driving force and arrangement.

On the other hand, even if the total number of teeth is not an odd number, the number of teeth in the gear portion may be reduced. In particular, when the toothless parts are close together due to the design, as shown in FIG. 5, the gear part cannot be formed, which may cause the inconvenience that the desired drive mode cannot be realized.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide an energy-saving cam drive device in which cams and gears can be easily designed, the parts can be made smaller, and the components can be made smaller.

Composition of the Invention The present invention has a motor, a drive gear that is decelerated from the motor, a cam surface that is in a meshing position with the drive gear and transmits power to another mechanism, and has at least two or more missing teeth. A cam drive device comprising: a cam gear having a toothless portion; and a control member that locks and biases the cam gear in response to when the toothless portion and the drive gear face each other; By adopting a configuration in which is a non-integer, it is possible to obtain a cam drive device that is small, energy-saving, and easy to design.

DESCRIPTION OF THE EMBODIMENTS The outline of the embodiment of the cam drive device is the same as that of the conventional example, and the characteristic parts of the embodiment of the present invention are schematically shown in FIGS. 6 and 7. 1 is a drive gear, and 2 is a cam gear. As shown in Figure 6,
The right half gear was in the position shown by the dashed dotted line in FIG. For the half, the number of teeth increases by one, and the relative position of the missing tooth part with the drive gear (other missing tooth part) also increases.
This makes it possible to set the position at 180°, which makes it easier to design the cam surface, etc. that extracts the driving force. Furthermore, being able to manufacture a larger number of teeth has the advantage that it is not necessary to increase the gear diameter. For example, when seven gears are required for cam power as shown in Figure 6, the conventional configuration uses an integer number of missing teeth (7 + 3 + 7 + 3 for a total of 20 gears in Figure 4). , so the pitch circle is φ10 with a module of 0.5.In contrast, in this embodiment, the number of teeth in the missing tooth part is a non-integer (Fig. 6), so it is 7 + 2.5 + 7 + 2.5. total of 19 pieces
Therefore, when the module is 0.5, the pitch circle becomes φ9.5, achieving a smaller diameter gear.

In addition, as shown in FIG. 7, in this embodiment, the toothless portion 2
It is possible to place one tooth 2s at the gear position between p and 2q by shifting it by half a tooth, and when moving between the toothless parts, it can be driven using the rotational force generated by meshing with the tooth 2s added above, realizing energy savings. It is possible.

Effects of the Invention The present invention is arranged so that the gear parts between the intermittent parts of the cam gear having the missing tooth parts are shifted by a non-integer number of gears, and the number of teeth is increased by one, producing the effect that the actual diameter becomes larger. , it is possible to realize a cam drive device that can reduce parts size, achieve energy saving, and is easy to design.

[Brief explanation of drawings]

1 to 3 are plan views for explaining the operation of the cam drive device, FIGS. 4 and 5 are plan views schematically showing the cam gear, and FIGS. 6 and 7 are plan views for explaining the operation of the cam drive device. FIG. 3 is a plan view schematically showing a cam gear in one embodiment. 1... Drive gear, 2... Cam gear, 2p, 2q
...teeth, 2s...teeth, 3...biasing spring, 4...
control rod.

Claims (1)

[Claims] 1 a motor, a drive gear that is decelerated from the motor, and a cam surface that is in a position to mesh with the drive gear and that transmits power to another mechanism;
A cam gear having three or more toothless portions, and a control member that locks and biases the cam gear in response to when the toothless portion and the drive gear face each other,
A cam drive device characterized in that the number of teeth in the toothless portion of the cam gear is a non-integer.