JPH0619183B2 - Clutch mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch mechanism capable of selectively switching a power transmission path in a video tape recorder (hereinafter referred to as VTR) or the like.

2. Description of the Related Art In recent years, a magnetic tape device such as a VTR often uses a mechanism for selectively transmitting the power of a driving source to a driven body.

An example of a conventional clutch mechanism will be described below with reference to the drawings. FIG. 7 and FIG. 8 are cross-sectional views of a main part of a conventional clutch mechanism. In FIG. 7, a driving gear 3 rotatably supported on a shaft 2 planted on a substrate 1 is rotationally driven by a motor (not shown). The clutch gear 4 that is always meshed with the driving gear 3 is
It is rotatably supported by a shaft 5 embedded in the substrate 1 and movable in the direction of the shaft 5, and is biased by a compression spring 6 in a direction toward the substrate 1. Further, the clutch gear 4 has a first surface 7a and a second surface 7b having different heights, and
It is mounted on a clutch plate 7 which is guided by a shaft 5 and slides on it, and meshes with a driven gear 8. The driven gear 8 is rotatably supported by a shaft 9 planted in the substrate 1.

Regarding the conventional clutch mechanism configured as described above,
The operation will be described below.

In the state of FIG. 7, the rotational force of the motor (not shown) is transmitted to the driven gear 8 via the driving gear 3. Here, when the clutch plate 7 moves leftward from the position shown in FIG. 7 and reaches the position shown in FIG. 8, the clutch gear 4 moves from the first surface 7a to the second position by the biasing force of the compression spring 6. The shaft 5 is guided and moved onto the surface 7b, and the mesh with the driven gear 8 is released. Conversely, if the clutch plate 7 is moved to the right from the state shown in FIG. 8, the clutch gear 4 is pushed up against the urging force of the compression spring 6 in the direction of the shaft 5, and the driven gear 8 is moved.
Will come to mesh with.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above configuration, when the clutch gear 4 moves from the position of FIG. 7 to the position of FIG. 8 by the urging force of the compression spring 6, the first driven gear 8 When the load on the first driven gear 8 and the tooth surface of the clutch gear 4 and each contact point between the tooth surface of the clutch gear 4 and the tooth surface of the driving gear 3 increases, the transmission load increases. Therefore, the frictional force between the tooth flanks that tends to hinder the movement of the clutch gear 4 in the direction of the axis 5 also increases, and depending on the balance between the urging force of the compression spring 6 and the frictional force, the clutch gear 4
Could not be moved, and the switching operation could not be performed reliably.

In view of the above-mentioned problems, the present invention provides a clutch mechanism having a simple structure and a reliable switching operation.

Means for Solving the Problems In order to solve the problems, the clutch mechanism of the present invention is a driving wheel, and an engaging member that moves in the radial direction of the driving wheel to engage and disengage with the driving wheel. A first urging unit that urges the engaging member in a direction to engage the driving wheel, supports the engaging member and the first urging unit, and engages with the engaging member. When driven, it moves between a driven wheel that rotates integrally with the driving wheel on the same axis, a non-contact position that does not contact the engagement member, and a contact position that can contact the engagement member. An abutting member, a second urging means for urging the abutting member in a direction opposite to the urging direction of the first urging means, and the engaging member at the abutting position. By abutting, the movement of the abutting member in the direction opposite to the urging direction of the second urging means is locked at a predetermined position. Locking means for locking the contact member at the predetermined position.
The engaging member is moved against the urging force of the urging means, and the engaging relationship between the engaging member and the driving wheel is released.

The present invention has the above-described structure, and by engaging and disengaging the engaging member interposed between the driving wheel and the driven wheel, the transmission / non-transmission of the power from the driving wheel to the driven wheel is surely selected. be able to.

Embodiment A clutch mechanism according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of the relevant part, and FIGS.
The figure is a plan view of the same.

In this embodiment, the driving wheel is the driving gear 12, the engaging member is the clutch member 13, the first biasing means is the spring 15, and the driven wheels are the driven gears 14 in the claims.
The contact member is the contact member 19, and the second biasing means is the compression spring 2.
0, the locking means corresponds to the shaft 17 and the locking surface 19b. The recess 19e corresponds to the restricting means.

In the figure, a driving gear 12 that is constantly driven to rotate by a motor (not shown) is rotatably supported on a shaft 11 that is planted in a substrate 10, and a protrusion 12a is provided at a predetermined interval on the inner periphery thereof. It is provided with. Further, the clutch member 13 having the first convex portion 13a engaging with the protrusion 12a is formed.
A driven gear 14 having a boss portion 14a which engages with a guide groove 13b provided in the guide member to slidably guide the clutch member 13 and a groove 14b which fits with the clutch member 13 is rotatable about a shaft 11. Is supported by. Further, the clutch member 13 is biased to the right in FIG. 1 by the spring 15 stretched on the driven gear 14, and is engaged with the protrusion 12 a provided on the driving gear 12. Therefore, the rotational force of the driving gear 12 is transmitted to the driven gear 14 via the clutch member 13. If the clutch member 13 moves to the left in FIG. 2 against the urging force of the spring 15, the engagement between the first convex portion 13a and the protruding portion 12a is released, and the driving gear 12 The rotational force is configured not to be transmitted to the driven gear 14. Also, the clutch member
13 has a second convex portion 13c that comes into contact with a contact member described later. The support plate 16 reciprocates on the substrate 10 between the non-operating position shown in FIG. 1 and the operating position shown in FIG. 3 by well-known means (for example, driving of a plunger by a solenoid), and It is adapted to be locked at the operating positions shown in FIGS. Shafts 17 and 18 are planted in the support plate 16, and engage with the guide grooves 19a of the contact member 19 to support the contact member 19 slidably in the left-right direction in FIG. The contact member 19 receives a biasing force to the left in FIG. 1 by the compression spring 20 fitted between the contact member 19 and the support plate 16, but the shaft 18 is in contact with the end of the guide groove 19a. The contact member 19 is locked at the position shown in FIG. here,
When the contact member 19 is moved to the right in FIG. 1 against the biasing force of the compression spring 20, the locking surface 19b contacts the shaft 17 and is locked at the position shown in FIG. There is. A first contact portion for contacting the second convex portion 13c of the clutch member 13 with the end portion of the contact member 19 to move the contact member 19 to the right from the position shown in FIG. 19c and a second contact portion 19d are provided. Further, the contact member 19 has a recess 19e that engages with the second convex portion 13c of the clutch member 13 after the clutch member 13 and the driving gear 12 are disengaged from each other and restricts the rotation thereof. It is provided.

Next, the operation will be described.

FIG. 1 shows a state in which the support plate 16 is locked in the non-operating position, and the second convex portion 13c of the clutch member 13 and the abutting member 19 are in a positional relationship where they do not abut. Therefore,
The clutch member 13 is biased by the spring 15 in the diagonally upper right direction in FIG. 1, and the first convex portion 13a is engaged with the protrusion 12a provided on the driving gear 12. For example, the driving gear 12 is the first
If the motor is driven to rotate clockwise in the figure, the clutch member 13 having the first convex portion 13a engaged with the protrusion 12a is also rotated clockwise. . Therefore, the rotational force of the motor (not shown) is also transmitted to the driven gear 14, and the driven gear 14 rotates clockwise.

Next, the operation of making the rotational force of the driving gear 12 non-transmitted to the driven gear 14 will be described. The support plate 16 is moved from the non-operating position shown in FIG. 1 to the operating position shown in FIG. 3 by known means, and is locked at this operating position. As a result, the first contact portion 19c and the second contact portion 19d provided on the end portion of the contact member 19 on the support plate 16 and the second convex portion 13c of the clutch member 13 can contact each other. It will be in a state. When the driving gear 12 further rotates clockwise from the state shown in FIG. 3, the second convex portion 13c comes into contact with the first contact portion 19c.
At this time, the load torque T is applied to the driven gear 14. Therefore, from the center of the shaft 11 to the protrusion 12 of the driving gear 12,
If the distance to the contact point between a and the first convex portion 13a of the clutch member 13 is R and the tangential force at the contact point is N, then N = T / R (1). If the friction coefficient at the contact point is μ, then
The frictional force f of the clutch member 13 in the sliding direction on the driven gear 14 is as follows: f = μ × N = μ × T / R (2) Therefore, in the state shown in FIG.
If the urging force of the spring 15 in the engagement direction of the clutch member 13 is P, the disengagement force F for moving 13 in the direction of disengagement from the driving gear 12 is F = f + P (3). Now, since the urging force of the compression spring 20 urging the contact member 19 to the left in FIG. 4 is set to be smaller than the detaching force F, the second convex portion 13c has the first Even if it abuts against the abutment portion 19c, the clutch member 13 and the driving gear 12 are not disengaged from each other, and the abutment member 19 is moved rightward against the biasing force of the compression spring 20. When the driving gear 12 is further rotated clockwise, the state shown in FIG. 4 is obtained. The shape of the contact member 19 from the first contact portion 19c to the concave portion 19e is the second convex portion of the clutch member 13. Even if the contact member 19 moves to the right due to contact with 13c, the locking surface 19b is not locked by the shaft 17. Driving gear 12
Continues to rotate clockwise, and the second convex portion 13c of the clutch member 13 comes into contact with the second contact portion 19d. As a result, the contact member 19 moves further to the right, but the movement of the contact member 19 to the right is restricted by the shaft 17 and the locking surface 19b.
The second convex portion 13a of the clutch member 13 and the projection of the driving gear 12 are moved to the position shown in FIG. 5 by moving leftward in FIG. The engagement with the portion 12a is released, and the rotational force of the driving gear 12 is not transmitted to the driven gear 14. At this time, the frictional force f between the protrusion 12a and the first convex portion 13a is reduced, and the clutch member 13 has the spring 15
However, since the biasing force of the spring 15 is set to be smaller than the biasing force of the compression spring 20, the contact member 19 resists the biasing force of the spring 15 as shown in FIG. Then, the clutch member 13 is moved to the left, and the projection 12a of the driving gear 12 and the first convex portion 13a of the clutch member 13 are completely separated. As described above, the present embodiment has an effect that a reliable switching operation can be obtained with an extremely simple configuration. Further, at this time, the second convex portion 13c of the clutch member 13
Is engaged with the concave portion 19e of the contact member 19, and the driven gear 14
Controls clockwise and counterclockwise rotation of. Therefore, even if vibration or the like is applied from the outside, the clutch member 13 and the driving gear 12 are not inadvertently engaged, and
Since the driven gear 14 does not rotate, a reliable disengagement operation can be performed.

Next, from the state of non-transmission of the rotational force shown in FIG.
Is moved to a position shown in FIG. 1 by a known means, the clutch member 13 moves to the right in FIG. 6 by the urging force of the spring 15 with the movement of the contact member 19 to move the first convex portion.
13a and the protrusion 12a are engaged with each other, and the rotational force of the driving gear 12 is transmitted to the driven gear 14 via the clutch member 13.

In the above description, the case where the driving gear 12 rotates in the clockwise direction has been described, but it is configured so that the same operation and effect can be obtained even in the case of rotating in the counterclockwise direction.

Further, the contact member 19 is provided with a concave portion 19e as a regulating means for regulating the rotation of the driven gear 14 after the driving gear 12 and the clutch member 13 are disengaged. It is not limited to.

Further, although the protrusion 12a is provided on the inner peripheral side of the driving gear 12, the shape is not limited to the illustrated shape, and a gear may be formed or pins may be planted.

EFFECTS OF THE INVENTION As described above, the present invention includes a driving wheel, and an engaging member that moves in the radial direction of the driving wheel to engage and disengage with the driving wheel.
A first urging unit that urges the engaging member in a direction to engage the driving wheel, supports the engaging member and the first urging unit, and engages with the engaging member. When driven, it moves between a driven wheel that rotates integrally with the driving wheel on the same axis, a non-contact position that does not contact the engagement member, and a contact position that can contact the engagement member. An abutting member, a second urging means for urging the abutting member in a direction opposite to the urging direction of the first urging means, and the engaging member at the abutting position. The second member of the contact member is brought into contact with the second member.
Locking means for locking movement in a direction opposite to the urging direction by the urging means at a predetermined position, and the abutting member at the predetermined position by the first urging means. Since the engaging member is moved against the urging force so that the engaging relationship between the engaging member and the driving wheel is released, the driving wheel and the driven wheel are extremely simple in structure. It is possible to obtain a very excellent effect of engaging / disengaging the engaging member intervening in the vehicle and reliably selecting transmission / non-transmission of power from the driving wheel to the driven wheel.

Further, by providing the contact member with a regulation means for regulating the rotation of the driven wheel after the driving wheel and the engaging member are disengaged from each other, the driven wheel is inadvertently against external vibration. Is prevented from rotating and the engaging member and the driving wheel are not engaged with each other, and an effect that a reliable disengagement operation can be performed is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a clutch mechanism according to an embodiment of the present invention, FIGS. 2 to 6 are plan views of the same embodiment, and FIGS. 7 and 8 are sectional views of a main part of a conventional clutch mechanism. It is a figure. 12 …… Driving gear, 13 …… Clutch member, 14 …… Driven gear, 15 …… Spring, 17 …… Shaft, 19 …… Abutting member, 19b ……
Locking surface, 19e: recess, 20: compression spring.

Claims (4)

[Claims] 1. A driving wheel, an engaging member that moves in a radial direction of the driving wheel to engage and disengage with the driving wheel, and urges the engaging member in a direction to engage the driving wheel. A first urging means, a member for supporting the engaging member and the first urging member, respectively, and a member that rotates integrally with the driving wheel coaxially when engaged with the engaging member. A drive wheel, an abutting member that moves between a non-abutting position that does not abut the engaging member and an abutting position that can abut the engaging member, and the abutting member is the first biasing member. Second urging means for urging in a direction opposite to the urging direction of the means, and the second urging means of the contact member by contacting the engaging member at the contact position. Locking means for locking the movement in the direction opposite to the urging direction at a predetermined position, wherein the contact member has the first member at the predetermined position. Against the biasing force of the energizing means to move the engagement member, a clutch mechanism engagement relationship between the original wheel and the engaging member is to be released. 2. The clutch according to claim 1, wherein the urging force of the engagement member by the first urging means is smaller than the urging force of the contact member by the second urging means. mechanism. 3. A driving wheel, an engaging member that moves in a radial direction of the driving wheel and has an engaging / disengaging relationship with the driving wheel, and urges the engaging member in a direction of engaging the driving wheel. A first urging means, a member for supporting the engaging member and the first urging member, respectively, and a member that rotates integrally with the driving wheel coaxially when engaged with the engaging member. A drive wheel, an abutting member that moves between a non-abutting position that does not abut the engaging member and an abutting position that can abut the engaging member, and the abutting member is the first biasing member. Second urging means for urging in a direction opposite to the urging direction of the means, and the second urging means of the contact member by contacting the engaging member at the contact position. Locking means for locking the movement in the direction opposite to the urging direction at a predetermined position, and the driven member after the driving wheel and the engaging member are disengaged from each other. Regulating means provided on the abutting member for regulating the rotation of the wheel, wherein the abutting member is engaged at the predetermined position against the urging force of the first urging means. A clutch mechanism in which a member is moved to release the engagement relationship between the engagement member and the driving wheel. 4. The clutch according to claim 3, wherein the urging force of the engaging member by the first urging means is smaller than the urging force of the abutting member by the second urging means. mechanism.