JPH06101159B2 - Power transmission device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device that can be used in a magnetic tape winding drive system of a magnetic recording / reproducing device or the like.

2. Description of the Related Art In recent years, magnetic recording / reproducing devices (hereinafter referred to as VTRs) have become increasingly multifunctional and cost-effective, and not only have normal recording / playback functions, but also fast forward, rewind playback, slow playback, and reverse playback. The still image playback function has begun to be adopted not only in high-end models but also in popular models. A conventional VTR winding drive system will be described below with reference to the drawings.

FIG. 5 is a schematic plan view of a tape drive system reel drive system of a VHS type VTR. Reference numeral 51 is a cassette half, which incorporates a supply reel 52 and a take-up reel 53. The state of FIG.
In the reproduction mode, the tape 54 pulled out from the cassette half 51 is wound around each running regulation post, and is wound around the cylinder 55 having the video head, and the cap stun shaft 56.
Crimped between the pinch roller 57 and the capstan motor
The rotational torque transmitted from 58 to the belt 59 and the flywheel 60 is sent out at a constant speed. Also, the capstan shaft
The tape 54a sent out from the motor 56 uses the reel motor 61 as a drive source, and rotates the take-up reel stand 64 in the arrow → direction via the motor pulley 62 and the idler 63, and the take-up reel stand.
The take-up reel 53 fitted over 64 is turned and wound. The rotation torque of the take-up reel stand 64 at this time is kept stable and appropriate by electrically controlling the reel motor 61.

Next, the reverse playback mode (a mode in which the tape is run in the opposite direction to the playback and the screen is viewed in reverse)
The capstan motor 58 rotates, and the tape crimped between the capstan shaft 56 and the pinch roller 57 shows a broken arrow (...
→) is sent to. The reel motor 61 moves in the opposite direction (...
→) and idler 63, using appropriate means,
Move to the position of a and move the supply reel base 65 in the direction of the broken line arrow (...
→), and as a result, the supply reel 52 fitted on the supply reel base 65 winds up the fed tape 54.

As can be seen from FIG. 5, the winding torque of the supply reel base 65 in this case has a long traveling distance and a large traveling load after being fed from the capstan shaft 56, as compared with the regenerating mode. In order to maintain stable and sufficient contact of the cylinder 55 with the head (not shown), it is necessary to set the torque to be usually larger than the take-up reel base torque in the reproduction mode. Also in this setting, circuits are electrically switched and controlled. Also, in the tape rewind and fast-forward mode, the tape
54 is wound around the 54b position in the cassette half 51, and after releasing the pressure contact between the pinch roller 57 and the capstan shaft 56, the reel motor 61 is controlled by high-speed rotation so that the idler
After 63, the supply reel base 65 or the take-up reel base 64 is driven at high speed to rewind the tape and fast-forward.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, as described above, in order to satisfy the appropriate conditions of the tape winding torque and the rotational speed in each mode, a dedicated reel motor is used and a complicated electric circuit is used. Therefore, there are problems such as high cost, low reliability, and the like.

In view of the above problems, the present invention uses a dedicated motor,
The present invention has a mechanical friction mechanism and a switching mechanism without using a complicated control circuit and has the same function, and provides an inexpensive and highly reliable power transmission device.

Means for Solving the Problems In order to solve the above problems, the power transmission device of the present invention is
An internal gear is formed on the supply and take-up reel bases, and one friction clutch unit each having a clutch gear that meshes with the internal gear is arranged so that it can be rolled and separated from each of the internal gears on both reel bases. On the side, a gear part capable of meshing with the disc gear of the friction clutch and a rubber idler part capable of rolling contact with the outer peripheral parts of the reel bases are coaxially formed. It is arranged such that the idler gear is driven by an appropriate means from a capstan drive motor or the like without using a dedicated reel motor as a drive source.

With the above-described configuration, the present invention uses the appropriate means for the clutch gears of both friction clutch units and the appropriate means in the state of meshing with the internal gears of both reel stands to move the idler gear to the take-up reel stand side. , The gear unit of the take-up side friction unit and the gear section of the idler gear mesh with each other by rolling contact, and the driving force transmitted to the idler gear by an appropriate means. Through the clutch unit, the torque set by the friction clutch on the winding side is transmitted to the winding reel stand. Also, when the idler gear is moved to the supply reel stand side, the torque set by the friction clutch on the supply side is similarly transmitted to the supply reel stand side. Therefore, by arbitrarily setting the torque setting of each friction clutch, the winding torque of the supply / take-up reel stand can be
It is possible to set an appropriate value. This is equivalent to modes such as recording, playback, fast-forward playback, reverse playback, and rewind playback in the VTR reel drive system. Next, if the idler gear is moved to the take-up reel stand side with the clutch gears of both friction clutch units separated from the internal gears of both reel stands by an appropriate means, the take-up side friction clutch The disk gear of the unit and the gear part of the idler gear do not mesh with each other, the rubber idler part makes rolling contact with the outer peripheral part of the take-up reel stand, and the driving force transmitted to the idler gear does not go through the friction clutch unit. , Directly to the take-up reel stand. or,
When the idler gear moves to the supply reel stand side, the driving force transmitted to the idler gear is directly transmitted to the supply reel stand in the same manner. This is equivalent to the fast-forward and rewind modes in the VTR reel drive system. As described above, according to the present invention, it is possible to provide the switching of the winding torque and the reduction ratio, which are required for the reel drive system of the VTR, without using a dedicated reel drive motor or a control circuit. is there.

Embodiment Hereinafter, a power transmission device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view (enlarged view of the portion of FIG. 5) of a VTR reel drive system as an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the take-up reel stand side from the center line thereof. Reference numeral 2 is a supply reel stand, 3 is a take-up reel stand, which is rotatably attached to the rotation support shafts 4 and 5 planted in the chassis 1, and forms internal gear portions 2a and 3a, respectively. is there. Explaining the take-up reel base side, the disc pulley 26 is rotatably fitted to the shaft 9 planted on the take-up clutch arm 7, and the washer 27 and the E ring 28 make it possible to provide an appropriate clearance in the thrust direction. Is held.

The disc pulley 26 has a friction member,
A felt 25 is attached, a disc gear 21 having a gear portion formed on the outer periphery is rotatably fitted and inserted, and a compression spring 24, a thrust receiving plate 23, and a thrust washer 22 are provided on the upper portion.
Is rotatably inserted, also serves as a thrust force receiving member of the compression spring 24, and has an internal gear portion of the take-up reel stand 3.
The clutch gear 20, which has a gear portion capable of meshing with 3a,
It is press-fitted and fixed to the cylindrical portion of the disc pulley 26.

With the above configuration, the disc gear 21 is pressed against the felt 25 of the disc pulley 26 by the compression spring 24, and the friction coefficient (μ _T ) between the felt 25 and the disc gear 21, the effective radius (R _T ) of the felt 25, the spring pressure of the compression spring 24 (P _T), to form a take-up friction clutch for transmitting the friction _{(T T = μ T · P} T · R T) to be determined.

The winding clutch arm 7 is rotatably attached to a rotating shaft 11 that is planted on the chassis 1, and the clutch gear 20 and the internal gear portion 3a of the winding reel stand 3 are in rolling contact with each other. It can be separated.

Further, on the side of the supply reel base 2 as well, a supply side friction clutch is formed, and the clutch gear 18 and the internal gear portion 2a of the supply reel base 2 can be rolled and separated freely by the rotation of the supply clutch arm 6. I am doing it.

Reference numeral 12 denotes a sub-board on which a pulley shaft 17 is planted, and the pulley shaft 17 is fixed to the chassis 1 so as to be located on the center lines of both reel stands. The idler arm A ₁₅ and the idler arm B ₃₇ are inserted into the pulley shaft 17, the idler arm B ₃₇ is rotatable, and the idler arm A ₁₅ is a sub-board 12.
The idler arm B ₃₇ and, with the appropriate Naru clearance vertically, the train wheel setting and is guided radially to the idler arm B _37, as that is slidably held by an E-ring 38, are the thrust regulating. The intermediate pulley 14 has a V groove for transmitting the belt from the drive source and a cylindrical pulley portion, and is rotatably inserted under the E ring 38 of the pulley shaft 17 by an E ring 39 to make it suitable. It holds and holds the thrust. An idler shaft 16 is press-fitted and fixed to a tip portion of the idler arm A ₁₅ , and an idler felt 29 is attached as a friction member around the idler shaft 16.

An idler pulley 30 is rotatably inserted in the idler shaft 16, and a compression spring 32, a thrust ring 33, and a thrust washer 35 are rotatably inserted in the lower portion thereof.
The ring 34 is configured to be thrust-fixed.
Further, an idler rubber tire 31 is fitted to the idler pulley 30 at a height facing the outer peripheral cylindrical portions of the internal gear portions 2a, 3a of the supply reel base 2 and the take-up reel base 3, and the supply Disc gear of the winding side friction clutch 19,21
The gear part 30a that can be engaged with the gear part of the
Is formed. Spring hook 1 of the idler arm A ₁₅
An idler crimping spring 36 is hung on 5a and the spring hooking portion 37a of the idler arm B _37.
Is guided by the idler arm B37 and slidable in the radial direction.
Is crimped to the upper cylindrical pulley portion of the intermediate pulley 14 with an appropriate crimping force. With the above configuration, the idler pulley 30 is pressed against the idler felt 29 of the idler arm A15 by the compression spring 32, and the friction coefficient (μ) between the idler felt 29 and the idler pulley 30 is reduced.
_I ), effective radius of idler felt 29 (R _I , compression spring 32
The idler friction clutch has a friction torque (TI = μI ・ PI ・ RI) that is determined by the spring pressure (P _I ) of.

The diameter of each pulley is arbitrarily set so as to satisfy the following conditions.

| B + C + F- (A + D + E)} / 2 = t> O ... (1) φA: Reel stand outer diameter φB: Reel stand inner teeth P, C, D φC: Disc gear P, C, D φD: Clutch gear P, C , D φE: Idler rubber tire outer diameter φF: Idler pulley gears P, C, D Next, the operation will be explained. With proper means (not shown), the supply clutch arm 6 and the winding clutch arm 7 are rotated. The clutch gears 18 and 20 of the friction clutch on the supply and take-up side are moved to the internal gear section 2 of the supply and take-up reel bases 2 and 3.
The drive source (not shown in the figure
When the intermediate pulley 14 rotates in the direction of the arrow (→) via the belt 13 from the capstan motor 58, etc. in the figure), the idler arm A ₁₅ and the idler arm B ₃₇ are integrated by the friction torque of the idler friction clutch.
The take-up reel table 3 side, and rotates around the pulley shaft 17, the gear portion 30a of the idler pulley 30 of the disk gear 21 and the idler arm A ₁₅ of the take-up friction clutch is engaged. Under the condition of [Formula 1], the idler rubber tire 31 of the idler pulley 30 and the outer peripheral cylindrical portion of the internal gear portion 3a of the take-up reel stand 3 maintain a constant clearance without contacting each other. (State of FIG. 2) In this state, the driving force transmitted by the belt 13 is transmitted to the disc gear 21 of the take-up side friction clutch through the intermediate pulley 14, the idler rubber tire 31, and the gear portion 30a of the idler pulley 30. Then, the friction clutch torque set by the winding-side friction clutch is transmitted to the clutch gear 20 and the internal gear portion 3a of the winding reel base 3. When the intermediate pulley 14 is rotated in the reverse direction (arrow direction → direction) via the belt 13, the idler arm A ₁₅ and the idler arm B ₃₇ are integrated as a result of the friction torque of the idler friction clutch, and the supply reel base 2 side to, and rotates around the pulley shaft 17, the gear portion 30a of the idler pulleys 30 of the disc gear 19 of the supply-side friction clutch and the idler arm a ₁₅ is engaged, by [1 expression] condition, the idler rubber tire 31 of idler pulley 30 The outer peripheral cylindrical portion of the internal gear portion 2a of the supply reel base 2 does not come into contact with each other and maintains a constant clearance.

The transmission of the driving force is similar to that on the winding side, and the friction clutch torque set by the supply-side friction clutch is transmitted to the internal gear portion 2a of the → clutch gear 18 supply reel base 2. The above operation is the arrow → rotation,
Reel winding operation in modes such as recording, playback, fast-forward playback, etc. of VTR, and arrow ... → rotation is reel winding operation in modes such as reverse playback, rewind playback, supply, take-up friction clutch, By setting each torque arbitrarily,
It is possible to set an appropriate reel base torque. In addition, by changing the diameter of each pulley within a range that satisfies the condition of [Formula 1], the reduction ratio from the intermediate pulley 14 to the supply reel stand 2 and the take-up reel stand 3 can be freely set. It is possible to form a reel winding drive system having a high degree of freedom such as the winding torque and the reduction ratio.

Next, another operation will be described with reference to FIGS. 3 and 4 by using appropriate means (not shown) to rotate the supply clutch arm 6 and the winding clutch arm 7 to supply the supply clutch arm 6 and the winding clutch arm 7. In a state where the clutch gears 18, 20 of the take-up friction clutch are separated from the internal gear portions 2a, 3a of the supply and take-up reel bases 2, 3 (at a distance of t or more in [1]), the drive source ( When the intermediate pulley 14 rotates in the direction of the arrow (→) via the belt 13 (not shown), the idler arm A15 rotates toward the take-up reel stand 3 side in the same manner as described above, and the idler pulley 30 moves. The idler rubber tire 31 of the take-up reel stand 3
The disk gear 21 of the take-up side friction clutch and the gear portion 30a of the idler pulley 30 are in contact with the outer peripheral cylindrical portion of the internal gear portion 3a, and are separated from each other (state of FIG. 4). Therefore, the driving force is transmitted not through the winding-side friction clutch, but directly through the idler rubber tire 31 of the idler pulley 30 from the intermediate pulley 14 to the internal gear of the take-up reel stand 3.
It is performed on the outer peripheral cylindrical surface of 3a.

Similarly, when the intermediate pulley 14 is rotated in the reverse direction (... →), the supply reel base 2 can be directly driven without using the supply-side friction clutch. The above operation corresponds to the reel winding operation of the VTR tape fast-forward mode in the arrow → rotation, the arrow winding operation in the tape rewind mode in the arrow →→ rotation, and within the condition of [1 set], From the intermediate pulley 14, supply, take-up reel stand 2,
It has the feature that the reduction ratio between 3 can be set freely.

EFFECTS OF THE INVENTION As described above, according to the present invention, a tape winding torque and a winding rotation speed (winding rotation speed) suitable for a multi-function mode can be obtained without using a dedicated reel driving motor or a complicated electric control circuit. It is possible to change the speed reduction ratio), and it is possible to greatly improve cost reduction and reliability improvement.

[Brief description of drawings]

FIG. 1 is a plan view of a reel drive system of a VHS type VTR according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a plan view of essential parts of the same embodiment, and FIG. 4 is a sectional view thereof. , Fig. 5 shows the conventional VHS
It is a principal part top view of the system VTR. 1 ... Chassis substrate, 2 ... Supply reel stand, 2a ... Supply reel stand internal gear section, 3 ... Take-up reel stand, 3a ... Wind reel stand internal gear section, 4,5 ... Reel stand Rotating spindle, 6 ...
Supply clutch arm, 7 ... Winding clutch arm, 8,9
...... Clutch shaft, 10, 11, 11 Rotation shaft, 12 …… Sub-board, 13
...... Belt, 14 ...... Intermediate pulley, 15 ...... Idler arm A, 15a ...... Spring hooking part, 16 ...... Idler shaft, 17 ...... Pulley shaft, 18 ...... Clutch gear (supply side), 19 ...... Disc Gear (supply side), 20 ... Clutch gear (winding side), 21
...... Disc gear (winding side), 22 ...... Thrust washer, 23 ...... Thrust receiving plate, 24 ...... Compression spring, 25 …… Felt, 26 …… Disc pulley, 27 …… Washer, 28…
… E-ring, 29 …… idler felt, 30 …… idler pulley, 30a …… gear, 31 …… idler rubber tire, 3
2 …… Compression spring, 33 …… Thrust ring, 34 …… E ring, 35 …… Thrust washer, 36 …… Idler crimp spring, 37 …… Idler arm B, 37a …… Spring hook, 38,
39 …… E-ring.

Claims (1)

[Claims] 1. A cylindrical outer shape, wherein an internal gear is formed on the inner surface,
A driven pulley rotatably provided on the support shaft, an input gear and an output gear are coaxially arranged, and a clutch unit having a constant torque transmission structure between the two gears and rotatably provided on the movable support shaft, The internal gear of the driven pulley and the output gear of the clutch unit are arranged so that they can be meshed with and separated from each other, and can be meshed with the pulley portion facing the outer peripheral cylindrical portion of the driven pulley and the input gear of the clutch unit. The gear part,
A driving pulley formed on the same shaft and rotatably provided on a movable support shaft is arranged so that it can be rolled and separated between the outer peripheral cylindrical portion of the driven pulley and the input gear of the clutch unit, and the output of the clutch unit. When the gear is in rolling contact with the internal gear of the driven pulley, the gear portion of the driving pulley is
When the output gear of the clutch unit is in rolling contact with the input gear of the clutch unit and transmits the torque set by the clutch unit to the driven pulley, and is separated from the internal gear of the driven pulley, the driving pulley is The power transmission device is characterized in that the pulley portion is in rolling contact with the outer peripheral portion of the driven pulley and directly drives the driven pulley without going through the clutch unit.