JPH0324908Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a speed governor that controls the speed of unidirectional movement of a reciprocating controlled member in its forward or backward path.

[Prior art]

Conventionally, as is already known, speed governors that control the speed of unidirectional motion used in soft eject devices for cassette tape recorders and cassette video tape recorders are centrifugal force type, inertia type, oil type governors, etc. Although it is possible to use the air method, the wind blowing air method is the one that is least susceptible to various requirements such as environmental changes and parts specifications. However, the wind blowing air system rotates the wind blower impeller at high speed to obtain braking force, so the speed increase ratio is larger than other types, and it has the disadvantage that noise is easily generated from the speed increase gear train and wind blower. In Japanese Utility Model Application Publication No. 57-193439, the applicant proposed a thin and compact shock absorber with a simple structure and easy to assemble.This shock absorber was equipped with a spring clutch as an overload safety device during reverse rotation, but the number of turns of the spring was If it is not over a certain level, it will slip during forward rotation, so there is a drawback that you cannot make that part very thin, and the number of parts in the spring clutch part increases.
Furthermore, there was a drawback that a subassembly process was required to fix the friction plate to the worm.

[Purpose of invention]

In view of the above-mentioned drawbacks, the present invention loosely fits a friction plate made of an elastic material such as rubber onto the worm shaft, and uses a biasing force depending on the direction of rotation of the worm shaft to sandwich the friction plate and integrate it with the worm shaft or make it free. The purpose of the present invention is to propose a speed governor that has a clutch action, eliminates a spring clutch, is thinner, and is cost-reduced.

[Structure of the idea]

The present invention consists of a speed-increasing gear train supported by a frame, a worm disposed at the final part of the speed-increasing gear train, an axial movement restriction section of a friction plate provided on the worm, and an axial movement restriction section facing the worm. a friction plate rotatably fitted to the worm, a friction plate holder whose end face faces the friction plate so as to be able to freely approach and separate from the worm, and which receives the worm in a rotatable and axially movable manner; and a peripheral wall surrounding the friction plate and the friction plate holder. It has a support portion that supports the device rotatably, and a cup that is integrally provided with the frame.

〔Example〕

The present invention will be explained with reference to an embodiment of the drawings. As shown in FIGS. 1 and 2, the speed governor is provided with three shaft portions 1a, 1b, and 1c on a synthetic resin frame 1, and supports gears 2, 3 of a speed increasing gear train and a worm wheel 4. At the same time, one end tenon 5a of the worm 5 disposed at the final part of the wheel train is fitted into the tenon receiving hole 1d of the frame 1, and the worm 5
A friction plate 6 is fitted on the other end 5b side so as to face the stepped portion 5c, and the other end 5b is fitted into the center hole 7a of the friction plate receiver 7 so as to be movable in the axial direction and rotatable. The tip end 7b of 7 is fitted into the center hole 8a of a cup 8 which is provided integrally with the frame 1, and the base plate 9 is attached to the top surface of the frame 1 with two supports 1e,
It is fixed at 1e.

The frame 1 and the base plate 9 are formed as shown in FIGS. 1 and 3, and the governor is fixed to the device with setscrews 10 fitted in the through holes 1f and 9a of the frame 1 and the base plate 9, Relief holes 1h and 9b for the cup 8 are formed on one side of the frame 1 and the base plate 9, and a fitting hole for the shaft and the support is formed in the base plate 9.

The gears 2 and 3 are a spur gear and a pinion 2a, respectively.
3a, and tooth tips 2b, 3b of gears 2 and 3.
The thickness of the gear is somewhat thin and a step is formed to reduce the axial dimension, so even if the spur gear parts are overlapped, gear deflection,
It is constructed so that the teeth do not stick together due to the inclination, etc. A controlled member consisting of a rack or a gear of a device (not shown) is meshed with the pinion 2a.

As shown in FIGS. 1 and 4, the friction plate 6 is made of an elastic material such as rubber and is loosely fitted to the other end 5b of the worm 5, and the end face 5 serves as an axial movement regulating portion of the friction plate 6.
c and an end face 7c of the friction plate receiver 7, and a plurality of arc-shaped friction parts 6b.

As shown in FIGS. 1 and 2, the cup 8 includes a flange 8b that is fitted into the locking groove 1g of the frame 1, and a friction plate 6.
A peripheral wall 8c is formed to surround the.

When the speed governor is assembled, the friction plate 6 and the friction plate receiver 7 are assembled to the worm 5, the cup 8 is further assembled, and one end of the tenon 5a is inserted into the tenon receiving hole 1d, and the swing is performed using this as a fulcrum. The cup 8 is fitted into the locking groove 1g.

The operation of the speed governor is such that when the gear 2 is rotated counterclockwise in FIG. 1 by the controlled member, the worm wheel 4 rotates counterclockwise and the worm 5 is rotated in the downward axial direction in FIG. The biasing force acts and rotates while being pushed toward the cup side, and the disc portion 6a of the friction plate 6 is pressed and pinched by the end face 5c of the worm 5 against the end face 7c of the friction plate receiver 7, and the friction plate 6 and the friction plate Since the receiver 7 rotates together with the worm 5, the rotation of the friction plate 6 deforms and expands the friction portion 6b outward, and the cup 8
The rotation of the worm 5 is braked by slidingly contacting the peripheral wall 8c of the worm 5.

On the other hand, when the gear 2 and the worm wheel 4 are rotated clockwise, the worm 5 is pushed toward the tenon receiving hole 1d and rotated, so the friction plate 6 is moved freely between the end surfaces 5c and 7c, and the worm 5 rotates. This results in unidirectional motion control where no braking is applied.

When the speed governor is configured as described above, there is no need to assemble the worm 5 and the friction plate 6 in advance, and the worm 5 and the friction plate 6 are assembled by fitting them one after another, and the worm 5 and the friction plate 6 are not fixed together. Therefore, there is no need for an overload safety device, the number of parts is small, assembly is easy and light, and costs can be reduced.

In FIG. 5, in order to tightly engage the worm 5 and the friction plate 6, a press plate 11 having a convex portion on the other end 5b is press-fitted and fixed, and a concave portion into which the convex portion is fitted is formed in the friction plate 6. This is a modified example.

In the above description, the friction plate 6 is formed of a disk portion 6a and a plurality of friction portions 6b as shown in FIG. 4, but it may be a disk-shaped friction plate with notches formed therein as in the conventional example. Also, depending on the material, a friction plate without notches may be used.

[Effect of idea]

As mentioned above, this invention utilizes the axial biasing force due to the rotational direction of the worm to rotate the worm together with the worm by sandwiching the friction plate, or to rotate freely to perform the clutch action, thereby eliminating the need for a spring clutch and reducing the number of parts. It has excellent practical effects such as fewer parts, lighter weight, and thinner thickness, which can reduce costs, and the friction plate is assembled with other parts by sequentially fitting it into the worm, making it easy to assemble. It is possible to provide a speed governor that performs the following functions.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a partially cutaway plan view of the main plate of the speed governor, Fig. 2 is an exploded sectional side view, and Fig. 3 is an external perspective view of the frame and main plate. ,
FIG. 4 is a front view (a) of the friction plate, a side view (b) of a cross-section taken along the Ro-Ro line of the front view, and FIG. 1... Frame body, 5... Worm, 6... Friction plate,
7...Friction plate holder, 8...Cup, 8b...peripheral wall.

Claims (1)

[Scope of Claim for Utility Model Registration] A speed-increasing gear train supported by a frame, a worm disposed at the final part of the speed-increasing gear train, an axial movement restriction portion of a friction plate provided on the worm, and axial movement. A friction plate that is rotatably fitted onto the worm so as to face the regulating part and expands outward during rotation, and a friction plate holder whose end face faces the friction plate so as to be able to freely approach and separate, and that receives the worm rotatably and movably in the axial direction. It consists of a cup that surrounds the friction plate and has a peripheral wall on which the expanded friction plate slides, and a support part that rotatably supports the friction plate holder, and is integrally provided with the frame, and that When the axial biasing force is in the cup direction, the worm and the friction plate are rotated together with the friction plate sandwiched between the axial movement regulating part and the friction plate receiver,
A speed governor characterized in that a friction plate is prevented from rotating together with a worm when the axial biasing force due to the rotation of the worm is opposite to the cup direction.