JPH07164340A - Screw fastening equipment - Google Patents

Abstract

PURPOSE:To obtain high fastening torque, allow operations to be surely 1 and quietly transmitted, and concurrently enhance durability by providing the equipment with a cam means which holds a driven element at a first cam position at the time of high speed/low torque, and allows the aforesaid element to be thrusted to a second cam position at the time of low speed/high torque. CONSTITUTION:At the time of a screwing position where torque applied to a driver shaft 4 is low, the cam driven element 22a of a cam means 22 is brought in contact with a cam 22b with pressure at a first cam position as a subordinate position, a sliding member 21 becomes capable of being linked with the driver shaft via the cam means 22, and a claw clutch 31 is out of a' meshing condition. This constitution therefore allows the driver shaft 4 to be rotated at high speed/low torque by an electric motor 2. Next, when the equipment is shifted to a screw fastening condition where torque is high, thrust is produced in the axial direction, the driven element 22a is thrusted to a second cam position against a coil spring 24 so as to be incapable of being linked with the cam 22b in the rotating direction, furthermore, the claw clutch 31 is connected, and the driver shaft 4 is thereby rotated at low speed/high torque by the electric motor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is, for example, 20 to 40 mm.
The present invention relates to a screw tightening machine which is also suitably used for attaching and detaching a relatively large screw having a diameter of.

[0002]

2. Description of the Related Art As a power transmission device for a screw tightener, for example, Japanese Patent Laid-Open No. 5-71599 discloses a power transmission device having an input shaft, an output shaft, a planetary gear and a torque-responsive gear transfer mechanism. The gear transfer mechanism is a drive member connected to the sun gear of the planetary gear mechanism, a driven member connected to the output shaft,
And a plurality of axially displaceable coupling elements arranged to be associated with the drive member and the driven member in the first position and with the planetary gear carrier and the driven member in the second position. Further, the driving member has the first cam device and the driven member has the second cam device, and when the torque resistance increases, the first cam device and the second cam device transfer the joint element from the first position to the second position. However, the high speed / low torque mode is shifted to the low speed / high torque mode.

[0003]

However, in the above-mentioned screw tightening machine of the prior art, the shaft coupling composed of the cam device is used for the transmission of the driving member and the driven member and the transmission of the planetary gear carrier and the driven member. Especially, in the low speed / high torque mode, the wear of the cam device becomes remarkable due to the increase of the torque resistance, and the cam device may malfunction due to long-term use.

When tightening a large diameter screw,
In the transfer process from the first position to the second position, the joint element is constantly displaced along the teeth on the inner circumference of the joint sleeve while continuously receiving torque resistance, which makes smooth transfer difficult. Furthermore, if a planetary gear mechanism with a high reduction ratio is used, the speed difference between the first position and the second position of the joint element becomes too large, which causes noise during transfer from the first position to the second position, and It becomes difficult to transfer the joint element.

An object of the present invention is to use a planetary gear mechanism having a high reduction ratio which can obtain a large tightening torque, to provide quiet transmission and reliable transmission, and to prevent wear of the cam device for long-term use. An object of the present invention is to provide a screw tightener that improves reliability and can be applied to screws having a relatively large diameter.

[0006]

In a screw tightening machine according to the present invention, a planetary gear mechanism is provided in a transmission system from an input shaft connected to a drive source to a driver shaft, and at the time of high speed / low torque, a sun gear of In a screw tightening machine that transmits rotation to the driver shaft and transmits rotation of the carrier of the planetary gear to the driver shaft at low speed / high torque, it is slidable in the axial direction to the gear shaft of the sun gear and A sliding member provided so as to be interlocked, a cam that is provided so as to be transmittable to the driver shaft, and has a first cam position and a second cam position that is on the sun gear side of the first cam position The cam follower is brought into pressure contact with the cam on the driver shaft side by the means, and the cam follower is held at the first cam position at the time of high speed / low torque and is connected in the rotational direction with the cam. The cam follower is pushed from the first cam position to the second cam position against the biasing means in response to the load torque at the time of low speed / high torque, and the cam and rotation direction cannot be interlocked. A configured cam device,
A transmission member, which is provided on the driver shaft so as to be slidable in the axial direction and interlockable with the rotational direction, and which is engaged with a sliding member via a bearing so as to be interlocked with the sliding member but not interlocking with the rotational direction, and a planetary gear. A meshing part that consists of a driving side meshing part provided on the carrier and a driven side meshing part provided on the transmission member so as to face the driving side meshing part, and can be connected when the transmission member is displaced to the sun gear side. It is equipped with a clutch.

In the screw tightener, the planetary gear mechanism may have a plurality of stages in order to obtain a necessary reduction ratio, and the drive side meshing portion of the meshing clutch slides axially on the carrier of the planetary gear. It is possible to provide an elastic member that is capable of rotating and interlocking with it in the rotational direction, and that urges the drive-side engagement portion toward the driven-side engagement portion between the carrier and the drive-side engagement portion. The cam of the cam device may be provided so as to be transmittable to the driver shaft via a shaft coupling that allows a gap in the rotation direction.

[0008]

In the above construction, when the torque applied to the driver shaft is small, the cam follower of the cam device is pressed against the cam on the driver shaft side by the biasing means at the first cam position. It becomes possible to interlock with the driver shaft in the rotational direction via the cam device, while the driven side meshing portion of the meshing clutch is in non-meshing state with the driving side meshing portion. Therefore, in this case, the rotation of the drive source is transmitted to the driver shaft through the input shaft, the sun gear, its gear shaft, the sliding member and the cam device in order, and the driver shaft is rotated at a high speed.

When the above state is changed to the screw tightening state in which the torque applied to the driver shaft is large, the cam follower of the cam device resists the biasing means in response to the load torque and moves from the first cam position to the second cam position. When the cam follower is pushed, the sliding member is displaced to the sun gear side together with the transmission member.
The driven side meshing portion of the meshing clutch moves to the sun gear side to mesh with the drive side meshing portion, and the meshing clutch is connected. Therefore, in this case, the rotation of the drive source is transmitted to the driver shaft through the input shaft, the sun gear, the planetary gear, its carrier, the meshing clutch and the transmission member in order, and the driver shaft is rotated at a low speed.

A drive side meshing portion of the meshing clutch is provided on the carrier of the planetary gear so as to be slidable in the axial direction and interlocking with the carrier in the rotation direction, and the drive side meshing portion is provided between the carrier and the drive side meshing portion. With an elastic member that urges the portion toward the driven side meshing portion, when the mesh of the drive side meshing portion and the driven side meshing portion face each other when the meshing clutch is connected, The elastic member is temporarily compressed as the meshing portion moves and the drive-side meshing portion retracts toward the sun gear side, so that forced meshing of both meshing portions is avoided and the cam follower is Also, the pushing movement to the second cam position is not hindered. When one peak and the other trough of both meshing parts are aligned due to the difference in rotation between the driver shaft and the carrier of the planetary gear, the drive-side meshing part returns by the repulsive force of the elastic member, and both meshing parts The gears are meshed with each other, and the mesh clutch is connected. Therefore, the transmission of rotation is reliably performed, and the vibration noise at the time of connection is suppressed to a relatively low level.

Further, when the cam of the cam device is connected to the driver shaft through a shaft coupling that allows a gap in the rotation direction, when the rotational speed difference between the low speed rotation and the high speed rotation of the driver shaft is large and the tightening torque is large. It is suitable for use when returning to a high speed / low torque state when a large reaction force receiving rod is attached to the housing. in this case,
If the drive source is reversely rotated within the gap range of the shaft coupling after screw tightening is completed, there will be a time delay when the cam follower moves from the second cam position to the first cam position. After the return is reliably performed, the moment acting on the reaction force receiving rod and the driver shaft is relaxed, and the screw tightener main body can be easily removed from the screw.

[0012]

1 is a sectional view of a screw tightening machine according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of the screw tightening machine shown in FIG. 1 at high speed / low torque, and FIG. 3 is a screw shown in FIG. FIG. 4 is a plan view of a shaft coupling used in the screw tightening machine shown in FIG. 1 when the screw tightening is performed, and FIG. 5 is used in the screw tightening machine shown in FIG. FIG. 8 is a plan view of the electric motor after reverse rotation after the completion of screw tightening of the shaft coupling.

In FIG. 1, a housing 1 is provided with a motor 2 as a drive source, and a planetary gear mechanism 5 having two stages is provided in a transmission system from an input shaft 3 connected to the motor 2 to a driver shaft 4. In that case, the first stage sun gear 6 is provided on the input shaft 3 and the second stage sun gear 8 is connected to the carrier 7 of the first stage planetary gear, and the second stage sun gear 8 is connected to the central sun gear 8 in the second stage. A plurality of planetary gears 11 are meshed with an internal gear 9 inside the housing 1 via a carrier 10.

The gear shaft 12 of the sun gear 8 extends downward and is rotatably supported by the driver shaft 4 via a bearing 13, and the sliding member 21 is spline-connected to the gear shaft 12 so as to be slidable in the axial direction. And a roller-like cam follower 22a that constitutes one side of the cam device 22 below the sliding member 21.
Is supported perpendicularly to the gear shaft 12, and the riding cam 2 that constitutes the other side of the cam device 22 is provided above the driver shaft 4.
2b is connected via a shaft coupling 23 so as to face the cam follower 22a. The shaft coupling 23 is a driver shaft 4
Two pins 23a that are vertically arranged evenly across the center axis line at the upper end, and arcuate elongated holes 23b that are bored concentrically with the driver shaft 4 so as to correspond to the pins 23a on the riding cam 22b. And each pin 23a is engaged with each corresponding elongated hole 23b. Sun gear 8 and sliding member 2
1, a compression coil spring 24 as an urging means is interposed along the gear shaft 12, and the compression coil spring 24 rides on the cam follower 22a and forms a V-shaped groove on the cam 22b. Alternatively, pressure contact is made at the flat second cam position q on the sun gear side.

Further, a drive side meshing portion 31a constituting one side of the meshing clutch 31 is axially slidably coupled to the lower end of the carrier 10 of the planetary gear 11, and the carrier 10 and the drive side meshing portion 31a. A compression spring 32 as an elastic member is interposed between and. Also, driver shaft 4
A cylindrical transmission member 33 is spline-connected slidably in the axial direction, and is engaged with the sliding member 21 via a ball bearing 34 so as to be interlockable with the sliding member 21 and unrotatably in the rotational direction. At the upper end, a driven side meshing portion 31b that faces the drive side meshing portion 31a and constitutes the other side of the meshing clutch 31 is provided. Further, an annular groove 35 is formed at a predetermined position on the outer peripheral portion of the transmission member 33, and the housing 1 is provided with a position detector 36 that detects the annular groove 35 with a proximity sensor.

In the above construction, when the torque applied to the driver shaft 4 is small and screwed in, the cam follower 22a of the cam device 22 is pressed against the cam 22b at the lower first cam position p, as shown in FIG. Therefore, the sliding member 21 can be interlocked with the driver shaft 4 in the rotation direction via the cam device 22, and at that time, the sliding member 21 is moved by the transmission member 3
3, the driven side meshing portion 31b of the meshing clutch 31 is not meshed with the drive side meshing portion 31a. Therefore, in this case, the rotation of the electric motor 2 is transmitted to the driver shaft 4 through the input shaft 3, the sun gear 8, the gear shaft 12, the sliding member 21, the cam device 22 and the shaft joint 23 in this order.

In the next stage, when the screw tightening state in which the torque applied to the driver shaft 4 is large is transferred, the cam device 22 generates thrust in the axial direction and the cam follower 22a receives the load torque, as shown in FIG. Depending on the compression coil spring 2
4 is pushed from the first cam position p to the upper second cam position q, and cannot be interlocked with the cam 22b in the rotational direction. At that time, the sliding member is accompanied by the pushing of the cam follower 22a. 21 is displaced upward together with the transmission member 33 via the ball bearing 34, and the driven side meshing portion 31b of the meshing clutch 31 is moved upward to drive the meshing portion 31a on the drive side.
The meshing clutch 31 is engaged by engaging with. Therefore, in this case, the rotation of the electric motor 2 is transmitted to the driver shaft 4 through the input shaft 3, the sun gear 8, the planetary gear 11, the carrier 10, the meshing clutch 31, and the transmission member 33 in this order.

When the meshes of the drive side meshing portion 31a and the driven side meshing portion 31b face each other when the meshing clutch 31 is connected, the compression spring 32 is temporarily moved as the driven side meshing portion 31b moves. The driving side meshing portion 31a is retreated upward by the repulsive force of the compression spring 32 at the time when the driving side meshing portion 31a retracts upward, and the one peak and the other valley of both meshing portions are aligned. After returning to the downward direction, the dog clutch 31 is connected.

After the completion of the screw tightening, the electric motor 2 is rotated in the reverse direction to move the shaft coupling 23 to the state shown in FIGS. 4 to 5 within the range of the gap between the pin 23a and the elongated hole 23b. The second cam position q moves to the first cam position p with a time lag, the high speed / low torque state is restored, and the dog clutch 31 is disengaged. When the transmission member 33 is displaced downward when the cam follower 22a is moved and the annular groove 35 on the transmission member 33 is detected by the position detector 36, the electric motor 2 is stopped based on the detection signal of the position detector 36. To be made.

[0020]

Since the screw tightening machine according to the present invention is configured as described above, a planetary gear mechanism having a high reduction ratio capable of obtaining a large tightening torque can be used, and the operation is quiet and reliable transmission can be obtained. Prevents abrasion of the cam device, improves reliability for long-term use, can be applied to screws with relatively large diameters, and requires less time to install and remove screws than hydraulically operated types that have been used in the past. It is possible to shorten it significantly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a screw tightening machine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of the screw tightener shown in FIG. 1 at high speed / low torque.

FIG. 3 is a cross-sectional view of essential parts of the screw tightener shown in FIG. 1 at low speed / high torque.

FIG. 4 is a plan view of the shaft coupling used in the screw tightener shown in FIG. 1 when screwing.

5 is a plan view of the shaft joint used in the screw tightening machine shown in FIG. 1 at the time of reverse rotation of the electric motor after completion of screw tightening.

[Explanation of symbols]

 2 electric motor 3 input shaft 4 driver shaft 5 planetary gear mechanism 8 sun gear 10 carrier 11 planetary gear 12 gear shaft 21 sliding member 22 cam device 22a cam follower 22b cam 24 compression coil spring 31 meshing clutch 33 transmission member 34 ball bearing

Claims (3)

[Claims] 1. A planetary gear mechanism is provided in a transmission system from an input shaft connected to a drive source to a driver shaft, and transmits the rotation of the sun gear to the driver shaft at high speed / low torque and at the time of low speed / high torque. In a screw tightener configured to transmit the rotation of a carrier of a planetary gear to a driver shaft, a sliding member provided on the gear shaft of the sun gear so as to be slidable in the axial direction and interlockable with the driver shaft in the rotation direction. A cam follower which is provided for transmission to the cam and has a first cam position and a second cam position on the sun gear side of the cam and a sliding member and which is pressed against the cam on the driver shaft side by the biasing means. The cam follower is held at the first cam position at high speed / low torque and can be linked with the cam in the rotating direction. The cam follower is pushed from the first cam position to the second cam position against the biasing means in response to the torque, and the cam device is configured so as not to be interlocked with the cam in the rotational direction; and the driver shaft. A transmission member axially slidable in the axial direction and interlockable with the rotational direction, engaged with a sliding member via a bearing so as to be axially interlockable and non-rotatably interlocked, and a carrier for the planetary gears. A meshing clutch that includes a drive side meshing portion provided on the drive side and a driven side meshing portion provided on the transmission member so as to face the drive side meshing portion, and is connectable when the transmission member is displaced to the sun gear side. And a screw tightening machine. 2. A drive side meshing portion of a meshing clutch is provided on a carrier of a planetary gear so as to be slidable in the axial direction and interlockable with it in a rotation direction, and the driving side is provided between the carrier and the drive side meshing portion. The screw tightener according to claim 1, further comprising an elastic member that urges the meshing portion toward the driven side meshing portion. 3. The screw tightener according to claim 1, wherein the cam of the cam device is provided so as to be transmittable to the driver shaft via a shaft coupling that allows a gap in the rotation direction.