JPH02283937A - Gear driving device and tape recorder - Google Patents

Abstract

PURPOSE:To reduce the size of the devices in the title and to decrease the collision frequency of parts by providing a worm wheel which is engaged with a worm to transmit drive and can be disengaged therefrom, in which teeth having pointed addenda and the same chordal pitch of addendum are formed only in one direction from the maximum engaging portion. CONSTITUTION:A worm 3 is rotated clockwise by a switching lever 6 to be meshed with a worm wheel 4. Accordingly, the rotation of a motor gear 1 is transmitted through a gear 2, the first gear 3a of the worm 3 and the second gear 3b to the worm wheel 4 to obtain large speed reduction. When a standard tooth form is laterally shifted and the addendum is pointed, the collision of addenda caused when the gear 3b and the wheel 4 mesh with each other can be decreased. Further, when the gear space on the addendum circle of the gear 3b and the gear space on the addendum circle of the wheel 4 are equalized, there is no possibility that two teeth of the gear 3b enter between the teeth of the worm 4 at the time of meshing. If teeth are provided only on the lower side of the maximum engaging portion of the gear 3b with the wheel 4, at the time of collision, they are easy to escape due to contact of teeth most adjacent to each other at the time of engagement.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gear drive device and a tape recorder using the gear drive device.

2. Description of the Related Art In recent years, gear drive devices have been widely used in precision machinery, small electronic devices, and the like. Therefore, it is strongly desired to make the equipment more compact and reduce the number of parts.

Conventionally, in the case of a gear drive device using a worm, the worm and worm wheel are always engaged, and when it is necessary to switch the drive, the spur gear provided at the front or rear stage is used for attachment and detachment. mechanism was used.

However, with the conventional device described in 1., there is a limit to how compact it can be made due to constraints such as the number of parts and the arrangement of spur gears, and it is also difficult to streamline assembly and reduce costs. It had a difficult problem.

In view of the above problems, the present invention provides a gear drive device that is compact and has a small number of parts.

Means for Solving the Problems In order to achieve the above object, the gear drive device of the present invention has the following features:
The device includes a worm that transmits rotation, and a worm wheel that transmits drive when engaged with the worm and that can be released from engagement with the worm.

Further, the gear drive device of the present invention is characterized in that, in the configuration described in 1, the tooth tip pitch of the worm and the tooth tip pitch of the worm wheel described in OII are made the same.

Further, the gear drive device of the present invention has the above-described configuration.
The worm is characterized by having a worm having teeth in only one direction from the maximum engagement portion with respect to the worm foil.

Further, the gear drive device of the present invention has the above-described configuration.
The worm wheel and the worm are characterized in that the tooth profiles of the worm foil and the worm have pointed tips.

Still, the gear drive device of the present invention has the above-described configuration.
When the worm engages with the worm wheel, a biasing member capable of biasing the worm so that the spacing becomes a predetermined value when the spacing for engagement is not reached due to a collision between tooth tips is provided. It is something that

Further, the gear drive device of the present invention includes a worm that transmits rotation, a gear configured coaxially with the worm, and a worm wheel that serves as a first transmission means that transmits drive only when engaged with the worm. The worm is further provided with a gear serving as a second transmission means that engages with a gear coaxial with the worm and transmits drive only when the engagement between the worm and the worm wheel is released.

Still further, the tape recorder of the present invention includes a member that engages with the worm wheel and loads and ejects the skein and throat, respectively, depending on the direction of rotation of the worm wheel;
The apparatus includes a member that engages with a gear configured coaxially with the worm and switches between fast forwarding and rewinding depending on the direction of rotation of the worm wheel, and the gear driving device.

For production The present invention has the following effects due to the above-described configuration.

Since the gear drive device of the first invention is a gear drive using a worm, it is possible to take a high reduction ratio, and by attaching and detaching the worm and worm wheel, the
Compared to the case where an attachment/detachment mechanism for spur gears is provided after iTl, the configuration is simpler and the number of parts can be reduced, making it suitable for downsizing.

In the gear drive device of the third invention, when the worm and the worm wheel engage, the tooth tip pinch of the worm wheel that occurs when the gear pitch is matched with a normal reference pitch circle is thicker than the tooth tip pinona of the ohm. This can prevent misalignment of the tooth tips due to this.

The gear drive device of the fourth invention can avoid the risk of the two-tooth gear located at the maximum engagement portion on the worm side colliding with the tooth tips of the two-tooth gear on the worm wheel side at the same time, and the beginning of meshing is always Each tooth can be engaged with one another.

In the gear drive device of the second aspect of the invention, the tips of the teeth of the worm and the worm wheel are shaped to be sharp, so that collision of the tips of the teeth when biting can be prevented.

In the gear drive device of the sixth invention, even if the tips of the teeth collide during meshing, the collision is relieved by a spring or the like, so if the worm wheel is then rotated, the collision between the tips of the teeth is canceled. , the normal engagement shape (2) can be achieved by the force of a deflected spring or the like. .

In the gear drive device shown in Fig. 6, the gear configured coaxially with the worm is not engaged at all when the worm wheel and the worm are engaged, and the engagement between the worm wheel and the worm is released. Since it is engaged with the gear serving as the second transmission means only when the drive is in use, it is possible to perform two types of driving by switching with a very compact configuration.

In the tape recorder of the seventh invention, the rotation of the worm in one direction is used as a loading drive by means of a transmission member in which the worm and the worm wheel are engaged, and the rotation of the worm in the opposite direction is used as an ejection drive. Since the reduced high torque rotation can be used in both directions, it can be used as a drive means suitable for the application. In addition, by engaging a gear configured coaxially with the worm and a member that drives switching between fast forwarding and rewinding operations, rotation in one direction is switched to the fast forwarding side, and rotation in the opposite direction is switched to the fast forwarding side. By switching the drive to the return side, the rotation speed is higher than that when the worm is decelerated, so that the drive means is suitable for this application where quick operation switching is required.

Furthermore, since the gear drive unit can be configured compactly, it is possible to downsize the tape recorder main body and reduce the number of parts.

Example Embodiments of the present invention will be described below based on the drawings.

. FIG. 1 shows a first state of a configuration diagram showing an outline of a first embodiment of a gear drive device of the present invention, and FIG. 2 shows a second state thereof.

In FIGS. 1 and 2, reference numeral 1 denotes a motor gear, which is directly connected to the motor and is configured to be able to rotate clockwise and counterclockwise. 2 is a two-stage gear, and the large diameter gear 2
a engages with motor gear 1 to perform deceleration. 3 is a worm, and three gears 3a, 3 configured on the same axis
The first gear 3a is always in engagement with the small diameter gear 2b of the two-stage gear 2, causing the worm 3 to rotate. The worm 3 also has a worm-shaped second gear 3b provided at the center and a third gear 3c which is a reduction gear with fewer teeth than the first gear 3a provided at the bottom. The 3° worm 3 is supported so as to be swingable around its upper part, and can rotate in either the left or right direction around the axis of the worm 3 depending on the rotation of the two-stage gear 2. A worm wheel 4 is engaged with the second gear 3b of the worm 3 to perform transmission. The worm v4 depends on the rotation of the worm 3 and can rotate in either the left or right direction, and each rotation is decelerated by one degree. A gear 5 is engaged with the third gear 3c of the worm 3 to perform transmission. The gear 6 can rotate in either direction depending on the rotation of the worm 3, and its speed is reduced depending on the worm shape I and 4, although not in the other direction.

Reference numeral 6 denotes a switching lever, which rotatably supports the worm 3 at its lower part, and allows the worm 3 to rotate so as to be able to engage with either the worm wheel 4 or the gear 5.

In the case of FIG. 1, the worm 3 is rotated clockwise by the switching lever 6 and is engaged with the worm wheel 4. Therefore, the rotation of the motor gear 1 is transmitted from the gear 2 to the first gear 3a of the worm 3 to the second gear 3b of the worm 3 to the worm wheel 4, thereby achieving a large deceleration.

In the case of FIG. 2, the worm 3 is rotated counterclockwise by the switching lever 6 and is engaged with the gear 6. Therefore, the rotation of the motor gear 1 is transmitted from gear 2 to first gear 3a of worm 3 to third gear 3C of worm 3 to gear 6, resulting in less deceleration than in the case of FIG. 1.

Figure 3 shows the second gear b of the worm 3 and the worm wheel 4.
This figure shows the tooth profile of the gear shown in Fig. 1, in which the standard tooth profile shown by the dashed line is shifted laterally, and the tooth tip is pointed as shown by the solid line.

Therefore, the second gear 3b of the worm 3 and the worm wheel 4
It is possible to reduce the possibility of collision between the tips of the teeth that occurs during meshing.

4 and 6 compare the gear pitch of the second gear b of the worm 3 and the worm wheel 4. FIG. FIG. 4 shows a normal gear pitch setting, in which the gear spacing on the pitch diameter is the same in order to obtain accurate meshing. Therefore, in the second gear 3b of the worm 3, the spacing between the gears on the pitch circle diameter and the spacing between the gears on the tip circle diameter are the same, but in the case of the worm wheel 4, the spacing between the gears on the pitch circle diameter is the same. The spacing between the gears on the tip circle diameter is large. In the case of such a combination, when the worm wheel/I/4 is engaged, the worm 3 is inserted between the teeth of the worm wheel/I/4.
There is a risk that the two teeth of the second gear 3b may get stuck. Fifth
In the figure, the spacing between the gears on the diameter of the tip circle of the second gear 3b of the ohm 3 and the spacing between the gears on the diameter of the tip circle of the worm wheel 4 are made the same. In this case, since the intervals between the gears on the pitch circle diameter do not match, some loss occurs in the transmission of rotation, but the amount is very small. When engaging, there is no fear that the two teeth of the second gear 3b of the worm 3 will get stuck between the teeth of the worm 4 and the meat as shown in FIG. 4, which is a great advantage.

FIGS. 6 and 7 show the state in which the second gear b of the worm 3 and the worm wheel 4 are engaged. 8th
In the figure, the second gear 3b of the worm 3 is provided with teeth on both sides (both upper and lower) of the maximum engagement portion with the worm wheel 4. In this case, smooth transmission occurs in the engaged state, but when engaged, the two teeth near the maximum engagement part collide at the same time, so there is a concern that the tips of the teeth will have difficulty escaping. . In FIG. 7, the second gear 3b of the worm 3 is provided with teeth only at the lower side of the maximum engagement portion with the worm wheel 4. In this case, since the teeth closest to each other come into contact first during meshing, there is an advantage that even if the tips of the teeth collide, they can easily escape.

In FIG. 8, 7 is a switching cam that controls the aforementioned switching lever 6, and is controlled by changing the distance from the center of the outer cam portion. Reference numeral 8 denotes a worm compression spring, which constantly pulls the switching lever 6 in the direction of crimping the worm 3 and the worm wheel/L/4, and presses the switching lever against the outer cam portion of the switching cam 7. Therefore, if the second gear 3b of the worm 3 and the tips of the teeth of the worm hoist V4 collide, the worm compression spring 8 is stretched and the tips of the teeth are prevented from being crushed, and the tensile force of the spring ensures correct meshing. can do.

By performing the above-described t74 configurations in combination or singly, it is possible to obtain a gear drive device that utilizes the attachment and detachment of a worm and a worm wheel.

Further, an embodiment of a tape recorder using the above-mentioned gear drive device will be described with reference to FIGS. 9 and 10.

FIG. 9 is a simplified diagram of the members for loading and extracting the cassette. In FIG. 9, reference numeral 9 denotes a two-stage gear, which is configured to reduce the rotation of the worm wheel 4. Reference numeral 1o denotes an eject slider, and although the details are omitted here, it engages with the gear 9 to perform a loading operation by moving upward, and performs an ejecting operation by moving downward. The eject slider 10 requires a large force to move the cassette tape, but since it is decelerated by the worm 3, high torque can be obtained and the ejecting speed is also gentle, allowing for smooth loading and Eject operation can be performed. FIG. 10 is a simplified diagram showing switching between fast forward and rewind drives of a tape recorder. Reference numeral 11 denotes a fast-forwarding lever, which is rotatably supported, and is rotated counterclockwise to fast-forward and clockwise to rewind.

Reference numeral 12 denotes a fast-forwarding cam, which is engaged with one end of the fast-forwarding lever and is arranged so that it performs a fast-forwarding operation by rotating clockwise and performs a rewinding operation by rotating counterclockwise. The fast-forwarding cam 12 is driven by the rotation of the gear 6.
Since appropriate deceleration is achieved through engagement with the gear 3c, speedy fast-forwarding and rewinding operations can be performed.

By using the worm 3 and worm wheel 4 as shown in Figures 9 and 10, in addition to the above-mentioned effects, it is possible to share the drive system and deceleration mechanism, which greatly contributes to downsizing and reducing the number of parts. can do.

Effects of the Invention The present invention can provide a compact gear drive device with a small number of parts by attaching and detaching the drive of the worm and worm wheel.

Furthermore, by forming the tips of the teeth of the worm and worm wheel into sharp shapes, it is possible to prevent the tips of the teeth from colliding during biting. Furthermore, by making the chordal pitches of the teeth of the worm and worm wheel the same, it is possible to prevent biting errors due to differences in tooth tip pitch that would occur if the gear pitches were matched using a normal reference pitch circle. In addition, it is possible to avoid the risk of the tooth tips of the two gears on the maximum engagement part on the worm side and the two teeth on the worm wheel side hitting the f1 nail at the same time, and at the beginning of meshing, each tooth is always It can be an engagement. In addition, even if the tips of the teeth collide during meshing, they are released by a spring, etc., so if the worm is rotated afterwards, the collision between the tips of the teeth is canceled, and the force of the strained spring etc. causes the teeth to be released from their normal engagement. The state can be set to the same state. In addition, since the worm is engaged with the gear serving as the second transmission means only when the engagement between the worm and the worm wheel is released, two types of driving can be performed with a compact configuration. When used in a tape recorder, when the worm and worm wheel engage, loading and ejecting are performed depending on the rotational direction, and when the worm and wormwheel are released, fast forwarding and rewinding are performed depending on the rotational direction. It is possible to perform four types of operations with different required torques and rotational directions. Furthermore, since the gear drive unit can be configured compactly, it is possible to downsize the tape recorder main body and reduce the number of parts.

[Brief explanation of drawings]

1 and 2 show an embodiment of the gear drive device of the present invention, FIG. 1 is a plan view showing the first state, and FIG. 2 is a plan view showing the second state. FIG. 3 is a plan view showing the tooth profiles of the worm and worm foil in the same device. Figures 4 and 6 show the gear pitch of the worm and worm boil in the same device, Figure 4 is a plan view showing the state in which the pitch is matched on the pitch circle diameter, and Figure 5 is a plan view showing the state in which the pitch is adjusted on the tip circle diameter. FIG. Figures 6 and 7 show the engagement state of the worm and worm foil in the same device, Figure 6 is a plan view in which the worm has 114 teeth above and below the engaging part, and Figure 7 shows the worm in the downward direction only. FIG. FIG. 8 is a plan view showing an example of worm drive switching in the same device. Figures 9 and 10 show an example of application of the device to a tape recorder, with Figure 9 being a plan view showing the loading and eject drive systems, and Figure 10 being a plan view showing the fast forward and rewind switching drive systems. It is a diagram. 1...Motor gear, 2...2-stage gear, 3
... Worm, 4 ... Worm wheel, 6 ... Gear, 6 ... Switching lever, 7 ...
...Switching cam, 8...Crimp spring, 9...
・2-stage gear, 1o...Eject nullider, 1
1... Rapid feed lever, 12... Rapid feed cam,
13... Rapid feed gear, 14... Reel stand, 16... Flywheel. Name of agent Patent attorney Shigetaka Awano and 1 other person 77 to Figure to-112 ↓ to Sla f da

Claims (7)

[Claims] (1) A gear drive device comprising: a worm that transmits rotation; and a worm wheel that transmits drive when engaged with the worm and that can be released from engagement with the worm. (2) The gear drive device according to claim 1, wherein the worm wheel and the worm are tooth-shaped with pointed tips. (3) The gear drive device according to claim 1, wherein the pitch of the worm and the chordal pitch of the tips of the teeth of the worm wheel are the same. (4) The gear drive device according to claim (1), wherein the worm has teeth in only one direction from the maximum engagement portion with respect to the worm wheel. (5) a worm that transmits rotation; a worm wheel that transmits drive while engaged with the worm; and a worm wheel that can be released from engagement with the worm; A gear drive device comprising: a biasing member capable of biasing the worm so that the spacing becomes a predetermined value when the spacing for engagement is not reached due to collision between the tips of the teeth. (6) a worm that transmits rotation; a gear configured coaxially with the worm; a worm wheel serving as a first transmission means that transmits drive only when engaged with the worm; A gear drive device comprising a gear serving as a second transmission means that engages with a gear coaxial with the worm and transmits drive only when the engagement of the worm wheel is released. (7) a worm that transmits rotation; a gear configured coaxially with the worm; a worm wheel serving as a first transmission means that transmits drive only when engaged with the worm; A gear serving as a second transmission means that engages with a gear coaxial with the worm to transmit drive only when the engagement of the worm wheel is released, and a gear that engages with the worm wheel serving as the first transmission means. , a member for loading and ejecting a cassette, respectively, depending on the rotational direction of the worm wheel, and a gear configured coaxially with the worm serving as the second transmission means, and fast forwarding and winding, respectively, depending on the rotational direction of the worm. A tape recorder comprising a member for switching back and forth.