JPH0727624B2 - Rotating drum device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to, for example, a video tape recorder (hereinafter referred to as VTR).
Abbreviated), which was made especially to improve the playback image quality of the VTR.
The present invention relates to a rotating drum device in which a head can be moved in the width direction of a magnetic tape to faithfully trace a magnetic recording trace.

[Conventional technology]

2 and 3 show the Japanese Patent Application No. 62-37 filed by the applicant earlier.
The main part of the rotary drum device proposed in JP-A-63-173217 is shown, and (4a) has the head (5) fixed to the tip to move the head (5) in the width direction of the tape. Is a drive unit for. Reference numeral (50) is a recess provided in a part of the upper drum (3) for accommodating the drive section (4a), and is formed slightly larger to adjust the position of the drive section (4a). The head is positioned using the position adjusting hole (51), and the yoke (47) is fixed with the screw (48).

In addition, (14) is a non-rotating electrode for supplying a control current to the drive section (4a), and (15) is a part of the pedestal (9) that rotates so as to make sliding contact with the contact (14). Electrodes, (16)
Is a connection part that is electrically connected to the drive part (4a) from the electrode (15) via the connection part (12) and the wiring board (11). The head (5) is electrically connected to the upper transformer (7) via the connecting portion (10), the wiring board (11) and the connecting portion (12).

FIGS. 4, 5, 6, 7, and 8 show the above-mentioned drive section (4a) in detail, and (41) is a non-magnetic plate having a head (5) attached to its tip. A spring, (43) a coil bobbin attached to the leaf spring (41), (44) a driving cylindrical coil wound around the coil bobbin (43), (42)
Is a leaf spring for supporting the coil bobbin (43) and allowing the coil bobbin (43) to move linearly by deforming together with the leaf spring (41), (45) a cylindrical permanent magnet, and (46) a cylindrical permanent magnet. (45) is a cylindrical permanent magnet with the same magnetic poles facing each other, (46a) is a pair of cylindrical permanent magnets (45),
A ferromagnetic center pole provided between (46),
(47) is a yoke. This yoke (47) is a leaf spring (4
1), (42), cylindrical coil (44), coil bobbin (4
3), a pair of cylindrical permanent magnets (45), (46) and a center pole (46a) are housed and held, and are divided into parts (47a), (47b), which are divided for easy housing and assembly.
It comes from (47c). (48a) is a screw hole for attaching and fixing the yoke (47) to the upper drum. (49)
Is a window provided in a part of the yoke (47). The head (5) projects through the window (49) and is arranged on the upper drum so as to be in sliding contact with the tape (13). The cylindrical coil (44) and the coil bobbin (43) are vertically movably arranged on an annular gear cup formed between the pair of cylindrical permanent magnets (45) and (46) and the center pole (46a) and the yoke. There is. Further, the leaf spring (41) is sandwiched between the yoke (47) portions (47a) and (47b), and the leaf spring (42) is held.
Is sandwiched between parts (47b) and (47c).

Referring to FIG. 5, the magnet (45) is connected to the yoke (47) (47).
Magnetic flux (D) is radially generated from the center pole (46a) toward the yoke due to the closed magnetic circuit formed by a) and (47b). Similarly, the magnet (46) creates a magnetic flux (E) by forming a closed magnetic circuit in the opposite direction with the portions (47b) and (47c), and the magnetic fluxes (D) and (E) both move in the same direction in the annular gear. Cross over. Thus, the combined magnetic flux of the magnets (45) and (46) traverses the cylindrical coil (44). When a current is applied to the coil (44) from the contact (14) through the electrode (15) and the connecting portions (12) and (16), the coil (44), the coil bobbin (43) and the head (5) are integrated. Move up and down in parallel. Thus, the head (5) is displaced in the tape width direction.

By the way, as can be seen from FIG. 3, since the lead wire of the coil of the head (5) is connected to the linear connecting portion (10), there arises a problem that the lead wire is broken. In order to solve this, a printed wiring board for connection was used. This is shown in FIG. In FIG. 8, (16a) is a printed wiring board for connection (hereinafter abbreviated as PWB) for supplying current to the head (5),
It is attached to the lower side of the leaf spring (41) shown in FIG. The connecting PWB is flexible and constitutes a flexible printed circuit. PWB for this connection
(16a) has a substantially arcuate shape as shown by the hatched line in (a) of FIG. The left end of the connecting PWB (16a) is bonded to the leaf spring (41) at the cross hatched area. Further, the end of the lead wire of the coil of the head (5) is electrically connected to this left end portion. Thus, there is no fear of breaking the lead wire of the coil of the head (5).

[Problems to be solved by the invention]

By the way, as shown in FIG. 8, the connection PWB (1
If the left end of 6a) is directly connected, when the center of the leaf spring (41) rises, the connecting PWB (16a) will move to the leaf spring (41).
The vertical movement of the leaf spring is caught on the outer periphery of the PWB (1
6a) was found to be disturbed. In the case of FIG. 8, since the connecting PWB (16a) is arranged below the leaf spring (41), the upward movement of the head (5) is obstructed. When placed on the upper side, the downward movement of the head (5) is impeded.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a head drive unit that eliminates obstruction to the vertical movement of the head and accurately traces a magnetic recording trace. Is.

[Means for solving problems]

The head drive unit according to the present invention is for flexible connection with a leaf spring as a support so as not to interfere with the vertical movement of the head.
A spacer having a thickness larger than the displacement amount of the head upward or downward is inserted between the PWB and the joint.

[Action]

In the present invention, since the spacer has a thickness larger than the amount of displacement of the head upward or downward, a space is created by the amount when the head is displaced upward, so vertical movement can be controlled without hindrance. .

〔Example〕

FIG. 1 is an overall configuration diagram of this system. In the figure,
(41) is a non-magnetic plate spring having a head (5) attached to its tip, (43) is a coil bobbin attached to the plate spring (41), and (44) is a coil bobbin (43) for driving. A cylindrical coil, (42) a leaf spring for supporting the coil bobbin (43) and allowing the coil bobbin (43) to move linearly by deforming together with the leaf spring (41), (45) a cylindrical permanent magnet, ( 46) is a cylindrical permanent magnet with the same magnetic poles as the cylindrical permanent magnet (45) facing each other, and (46a) is a ferromagnetic material provided between a pair of cylindrical permanent magnets (45), (46). The center pole of the body, (47) is the yoke. This yoke (47) is a leaf spring (41), (42), a cylindrical coil (44),
Coil bobbin (43), pair of cylindrical permanent magnets (45),
(46) and the center pole (46a) are housed and held, and are divided into parts (47a), (47b) and (47c) so as to be easily housed and assembled. (16a) is a connection PWB for supplying current to the head (5)
Then, put a leaf spring (4
It is attached to 1). The spacer (53) is made of a glass-filled epoxy resin substrate (which is called a glass epoxy substrate in the field). (48a) is a screw hole for attaching and fixing the yoke (47) to the upper drum. (Four
9) is a window provided in a part of the yoke (47). Head (5) protrudes through this window (49) and tape (13)
Is disposed on the upper drum for sliding contact with. The cylindrical coil (44) and the coil bobbin (43) are composed of a pair of cylindrical permanent magnets (45), (46) and a center pole (46).
It is movably arranged vertically in an annular gear formed between a) and the yoke. Further, the leaf spring (41) is held between the portions (47a) and (47b) of the yoke (47), and the leaf spring (42) is held between the portions (47b) and (47c). .

Next, the operation will be described. The magnet (45) is the yoke (47)
Magnetic flux (D) is radially generated from the center pole (46a) toward the yoke due to the closed magnetic circuit formed by the parts (47a) and (47b). Similarly, the magnet (46) is
b) and (47c) form a closed magnetic path in the opposite direction to generate a magnetic flux (E), and both magnetic fluxes (D) and (E) traverse the annular gear in the same direction. Thus cylindrical coil (44)
The total magnetic flux of the magnets (45) and (46) intersects. From coil (44) to contact (14) to electrode (15), connection (1
When an electric current is passed through 2) and (16), the coil (44), the coil bobbin (43) and the head (5) are united to make a vertical straight line motion. Thus, the head (5) is displaced in the tape width direction.

In FIG. 1, the coil bobbin (43) and the head (5) move up and down, the spacer (53) and the connecting PWB (1
6a) also moves up and down at the same time. However, the connection method between the conventional leaf spring (41) and the connection PWB (16a) (see FIG. 8)
Then, the PWB for connection (16a) can move without hitting other parts during downward operation (that is, it can bend downward)
However, when moving upward, the connecting PWB (16a) contacts the leaf spring (41), and since the connecting PWB (16a) cannot be extended, it is above the free end of the leaf spring (41). It was in the form that the movement in the direction was suppressed. But first
As shown in the figure, a spacer (5 with a glass epoxy substrate having a thickness (0.3 mm in the example) slightly larger than the amount of upward displacement (5
By inserting 3) between the leaf spring (41) and the connecting PWB (16a), the connecting PWB does not come into contact with the leaf spring (41) near the holding when moving upward. Therefore, the vertical movement will be performed without interference.

The glass epoxy substrate was used as the spacer.
This is because this material is not affected by temperature changes.

〔The invention's effect〕

By inserting the spacer as described above, the upward movement of the head is not obstructed. Therefore, if the thickness of the spacer is within the range, the vertical movement of that amount can be effectively performed.

[Brief description of drawings]

FIG. 1 is a detailed sectional view of a head drive unit according to the invention, FIG.
The figure is a cross-sectional view showing the main part of the rotary drum device proposed by the applicant in the earlier patent application, FIG. 3 is its plan view, FIG. 4 is a plan view of the head drive section, and FIG. Fig. 4 is a sectional view, Fig. 6 is a front view of Fig. 4, and Fig. 7 (a) is a plan view of the lower spring (however, it is shown by a diagonal line having a plan shape of the connecting PWB shown in Fig. 8). ), FIG. 7 (b) is a plan view of the upper spring, and FIG. 8 is a detailed sectional view of the head drive portion of FIG. In the figure, (5) is a head, (41) is a leaf spring, and (42)
Is a leaf spring, (43) is a bobbin, (44) is a coil, (45),
(46) is a permanent magnet, (46a) is a center pole, (47)
Is a yoke, (53) is a spacer, and (16a) is a connecting PWB. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A permanent magnet, a yoke having a magnetic gap formed around the permanent magnet and held in the permanent magnet, a coil arranged in the magnetic gap, and a coil held in the yoke. A leaf spring that movably carries the coil, a magnetic head that is provided on the leaf spring that moves according to the movement of the coil due to energization of the coil, and a flexible connector that connects the output of the coil and the head to an external circuit. In a rotary drum device including a flexible connecting substrate, a spacer having a thickness larger than an amount of upward or downward displacement of the magnetic head is provided at a connecting portion between the leaf spring and the flexible connecting substrate. Rotating drum device.