JP2003056666A - Rack and pinion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent mechanical lock generated by a pinion pressing a rack when it is engaged with the rack in a rack and pinion device of an engagement/ disengagement type in which the rack to be engaged with the pinion is normally separated from the pinion, and movable to advance to be engaged with the pinion, and backward to be disengaged from it. SOLUTION: Tip parts of a plurality of teeth 1a and 1b at tip parts of the rack 1 are cut along the addendum circle Ct of the pinion 2, so that a contact angle θ at a position where the tip tooth 1a of the rack 1 is firstly engaged with the pinion 2 becomes small. Partial force Fh in a horizontal direction to be consumed for driving the rack 1 becomes larger among force F transmitted from the pinion 2 to the rack 1 for driving the rack 1, thereby mechanical lock can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rack-and-pinion device including a linear rack and a pinion that meshes with the rack.

[0002]

2. Description of the Related Art Conventionally, a rack-and-pinion device is generally of a constant mesh type in which the rotary motion of a pinion driven by a motor by constantly meshing the two is converted into a reciprocating linear motion of a rack. Apart from such a type, from a pinion arranged at a predetermined position and a rack which is normally separated from this pinion, and which moves forward to engage with the pinion, and retracts to disengage from the pinion. There is also a detachable rack and pinion device.

Such an engagement-and-disengagement type rack and pinion device is used, for example, in a disk reproducing device for a vehicle which employs a suspension structure for damping vibration during traveling. This type of disk reproducing device for a vehicle has a suspension chassis supported by a lower chassis via a damper and a damper spring, a disk reproducing mechanism section attached to this suspension chassis, and a disk inserted into this disk reproducing mechanism section. , A suspension mechanism for ejecting the disc, which fixes the suspension chassis to the lower chassis and the upper chassis when inserting and ejecting the disc, and releases the suspension chassis from the fixation to the lower chassis and the upper chassis when reproducing the disc. Equipped with locking means.

FIG. 3 (a) is a schematic plan view showing a lower chassis and suspension chassis assembly of a conventional vehicle-mounted disc reproducing apparatus, and FIG. 3 (b) is a schematic side view of the lower chassis assembly. The right side of FIG. 3A is the front part of the device for inserting and ejecting the disc, the left side is the rear part of the device, the upper side is the right side part of the device, and the lower side is the left side part of the device. In FIG. 3, a disk transport mechanism 11 is arranged at the front part of the lower chassis 10. The disk transport mechanism 11 includes a feed plate 12 made of sheet metal, and a rotation support shaft 13 provided at the center of both sides of the feed plate 12 so as to project outward is rotatably supported by the lower chassis 10. Feed plate 1
A feed roller 14 is rotatably provided at the rear ends of both side portions of 2. The feed plate 12 has a rotary support shaft 13
By a torsion coil spring 15 provided around the disk, it is urged to rotate in a clockwise direction, and in a normal state, as shown in the front view of FIG. The disc insertion opening 32 formed in the front plate 30a of the upper chassis 30
The disc D inserted from above is conveyed so as to be sandwiched between the feed roller 14 and the disc guide 31.

The suspension chassis 20 includes damper mechanisms 21, 22, 23 composed of an oil damper and a coil spring.
Thus, the lower chassis 10 is supported at three points. A turntable mechanism and an optical pickup mechanism are attached to the opening 24 of the suspension chassis 20, and a clamp arm of a disc clamp mechanism that pushes the disc against the turntable is rotated via a suspension lock mechanism 25 provided on the left inner surface. It is movably attached. The suspension lock mechanism 25 includes a suspension lock member 26 provided on the left side surface of the suspension chassis 20 so as to be slidable in the front-rear direction.
0 is provided with a rack 27 that can mesh with a pinion 28, and a cam surface 29 is provided on the lower surface of the front end portion of the rack 27.
Is formed and is locked to the rotary shaft of the feed roller 14 from above.

When a user inserts a disc into the apparatus through the disc insertion opening 32, a signal from a photosensor which detects the insertion of the disc causes the disc carrying motor 16 to rotate and the feed roller 14 to rotate. A disk guide 31 formed on the upper chassis 30 and the upper chassis 14 draws it into the apparatus while centering it in the center. When the disc is pulled into the apparatus, the suspension lock mechanism 25 operates by the rear end of the disc, the suspension lock member 26 slides in the forward direction, and the rack 27 of the suspension lock member 26 meshes with the pinion 28. The rack 27 slides forward by the pinion 28 driven by
The feed roller 14 is pushed down by the cam surface 29 formed on the lower surface of the front end thereof, and the feed plate 12 rotates counterclockwise about the rotation support shaft 13. As a result, the feed roller 14 is separated from the upper chassis 30, and the state is maintained by the bottom surface of the cam surface 29. At the same time, the disc clamp arm descends to position the disc on the turntable, and the locking portion 26a at the rear end of the suspension lock member 26 is moved to the lower chassis 1.
The suspension chassis 20 is held in a floating state by the damper mechanisms 21, 22, and 23 apart from the locking portion of 0, and the disc is reproduced.

[0007]

However, in the above-mentioned conventional vehicle-mounted disc reproducing apparatus, when the disc is pulled into the apparatus, the suspension lock member 26 slides forward, and the rack 27 thereof meshes with the pinion 28,
The rotating pinion 28 pushes the rack 27, which sometimes causes a mechanical lock in which the mechanism does not move. FIG. 5 shows such a state. From the state where the rack 27 moves forward with respect to the rotating pinion 28 in (a), the tip teeth 27a of the rack 27 in (b) move to the pinion 28.
In many cases, a mechanical lock is generated when the tooth 28a is first meshed with the tooth 28a. If the mechanical lock does not occur and the meshing is successful as shown in (c), the rack 27 is driven by the pinion 28 and can further advance. The cause of the mechanical lock is that the force F transmitted from the pinion 28 to the rack 27 in (b) is the resultant force of the horizontal component force Fh and the vertical component force Fv, and the first meshing tooth 28a.
Depending on the contact angle between the tooth and the tooth 27a, the vertical component force Fv
The tooth 28a is often larger than the tooth 27a.
The mechanical lock is generated by pressing.

The present invention solves such a conventional problem, and a rack and pinion device capable of preventing a mechanical lock and ensuring a meshing operation in a disengageable rack and pinion device. The purpose is to provide a device.

[0009]

In order to achieve the above object, a rack and pinion device of the present invention includes a pinion arranged at a predetermined position and transmitting a driving force, and a pinion in a normal state with respect to the pinion. A rack that is spaced apart, meshes with the pinion by moving forward, and is disengaged from the pinion by retracting, and a tip portion of a plurality of teeth at the tip of the rack is cut off. This configuration reduces the contact angle at the position where the tip teeth of the rack first mesh with the pinion, so that the rack is driven by the force transmitted from the pinion to the rack. The part that is spent on is increased, and it is possible to reliably prevent mechanical lock.

The rack and pinion device of the present invention is characterized in that the tip teeth of the rack mesh with the pinion in the vicinity of a vertical line of the rack passing through the center of the pinion. With the configuration, most of the force transmitted from the pinion to the rack for driving the rack is spent for driving the rack, so that mechanical lock can be reliably prevented.

The rack and pinion device of the present invention is characterized in that the tip teeth of the rack mesh with the pinion inside the addendum circle of the pinion and outside the pitch circle. With this configuration, the tip teeth of the rack can be reliably meshed with the teeth of the pinion.

Further, the rack and pinion device of the present invention is characterized in that a plurality of teeth at the tip of the rack are cut off along substantially the tip circle of the pinion. Thereby, the cutting process of the teeth of the rack tip can be performed with high accuracy.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a tooth type diagram for explaining the basic configuration of the embodiment of the present invention, so that the position at which the tip tooth 1a of the rack 1 first meshes with the tooth 2a of the pinion 2 is substantially directly below the pinion 2. The tooth tops of the two teeth at the tip of the rack 1 are cut off along a substantially tip circle Ct of the pinion 2. The tip tooth 1a of the rack 1 is cut off slightly inside the tip circle Ct of the pinion 2 so as to mesh with the tooth of the pinion 2 with a meshing allowance t.
The second tooth 1b from the tip of the rack 1 is cut off slightly outside the tip circle Ct of the pinion 2 so that the tooth 2a of the pinion 2 that is trying to mesh first may not come into contact.
The meshing allowance t can be set arbitrarily between the inside of the pinion two tip circle Ct and the outside of the pitch circle Cp.

When the rack 1 moves forward in the direction of the arrow and tries to mesh with the pinion 2 rotating in the same direction, when the tip teeth 1a of the rack 1 come to a position just below the pinion 2,
When the tip teeth 1a and the teeth 2a of the pinion 2 are designed to mesh with each other, the force F transmitted to the rack 1 by the pinion 2 is the horizontal component force Fh rather than the vertical component force Fv. Is increased, the rack 1 is reliably driven by the pinion 2 and no mechanical lock occurs. The horizontal component force Fh is a straight line formed by a vertical line V of the rack 1 passing through the center O of the pinion 2 and a contact point between the center O of the pinion 2 and the teeth 2a of the pinion 2 and the tip teeth 1a of the rack 1. When the contact angle θ constituted by is zero, that is, the contact point coincides with the vertical line V, it becomes maximum, and most of the force transmitted from the pinion 2 to the rack 1 is spent for driving the rack 1. How much this contact angle θ is taken depends on at which position in the first stroke of the rack 1 the tip teeth 1a of the rack 1 and the teeth of the pinion 2 are meshed, which is a problem of mechanical design. is there. Therefore, in some cases, the teeth of the second tooth 1b in FIG. 1 may be engaged with each other, and the teeth of the rack 1 become higher by that amount (the portion to be cut out is reduced).

FIG. 2 shows how the rack 1 and the pinion 2 in this embodiment mesh with each other. The rack 1 advances with respect to the rotating pinion 2 (a), and the tip teeth 1a of the rack 1 first mesh with the teeth 2a of the pinion 2 (b).
At this time, since the tooth tip of the second tooth 1b is also cut off, it does not interfere with the tip tooth 1a. Further, among the forces F transmitted from the pinion 2 to the rack 1, the horizontal component force Fh is larger than the vertical component force Fv, so that the rack 1 is reliably driven by the pinion 2 and the second component force Fh. The tooth 1b can also mesh with the tooth 2b next to the pinion 2 (c).

[0016]

As described above, the rack and rack of the present invention is
The pinion device is arranged at a predetermined position and the driving force is transmitted to the pinion, and the rack is normally separated from the pinion. When the rack advances, the rack meshes with the pinion and when the rack retracts, the mesh with the pinion disengages. In the engagement-and-disengagement rack-and-pinion device, the tips of the teeth of the rack were cut off, so the contact angle at the position where the rack's tip teeth first mesh with the pinion is small, and the rack is driven. Since a part of the force transmitted from the pinion to the rack for driving the rack is increased, the mechanical lock can be prevented and the meshing operation can be ensured.

[Brief description of drawings]

FIG. 1 shows a rack and a rack according to an embodiment of the present invention.
Schematic diagram illustrating the meshing principle of the pinion device

FIG. 2 shows a rack and a rack according to an embodiment of the present invention.
Schematic diagram illustrating the operation of the pinion device

3A is a schematic plan view of a lower chassis and a suspension chassis assembly of an optical disc reproducing apparatus in a conventional example, and FIG. 3B is a schematic side view of a lower chassis assembly of an optical disc reproducing apparatus in a conventional example.

FIG. 4 is a schematic front view of an upper chassis in a conventional example.

FIG. 5 is a schematic diagram illustrating the operation of a rack and pinion device in a conventional example.

[Explanation of symbols]

1 rack 1a Tip tooth 2 pinion 10 lower chassis 11 Disc transport mechanism 12 Feed plate 13 rotation spindle 14 Feed roller 15 torsion coil spring 16 disk transport motor 20 suspension chassis 21, 22, 23 Damper mechanism 24 opening 25 Suspension lock mechanism 26 Suspension lock member 27 racks 28 Pinion 29 Cam surface 30 upper chassis 31 disk guide 32 Disc insertion slot

Claims (4)

[Claims] 1. A pinion which is arranged at a predetermined position and which transmits a driving force, and which is normally separated from the pinion, is engaged with the pinion by moving forward, and is meshed with the pinion by moving backward. And a rack for removing the tooth tips of a plurality of teeth at the tip of the rack.
Pinion device. 2. The rack and pinion apparatus according to claim 1, wherein a tip tooth of the rack meshes with the pinion near a vertical line of the rack passing through a center of the pinion. 3. The rack according to claim 1, wherein a tip tooth of the rack meshes with the pinion inside an addendum circle of the pinion and outside a pitch circle.
And pinion device. 4. The rack and rack according to claim 1, wherein a plurality of teeth on the tip of the rack are cut along substantially the tip circle of the pinion. Pinion device.