Connector lock structure

A lock operating member 25 is mounted on a connector housing 21, and in this condition lock balls 35 are mounted one by one in respective ball support holes 24 while elastically displacing elastic engagement members 27 radially outwardly. The mounted lock balls 35 are held in the respective ball support holes 24 by the respective elastic engagement members 27, and therefore even if the posture of a female connector is changed, the operation can be carried out easily.

BACKGROUND OF THE INVENTION 
This invention relates to a structure for locking connectors together in a 
fitted condition. 
For example, for charging an electric vehicle, there are used a vehicle 
body-side connector, connected to a car battery and fixed to a vehicle 
body, and a charger-side connector connected to a charger via a flexible 
cable. To start a charging operation, the charger-side connector is fitted 
in the vehicle body-side connector. In this case, in order to prevent the 
charger-side connector from disconnecting from the vehicle body-side 
connector during the charging operation, it is necessary to provide lock 
mechanism to hold the two connectors in the mutually fitted condition. In 
view of the strength reliability and the operability, it is proposed to 
use a ball lock mechanism, used in the connection of a gas pipe. 
However, in such a ball lock mechanism, in order to provide a uniform 
engagement force in a circumferential direction, ball support holes are 
provided, for example, at four positions, respectively, which are 
circumferentially spaced 90 degrees from one another, and lock balls are 
received in these ball support holes, respectively. In a pre-assembled 
condition in which the lock balls are received respectively in the ball 
support holes, the ball support holes are open downwardly, and therefore 
there is a risk that the lock balls are removed from the respectively ball 
support holes. Therefore, some measures must be provided for preventing 
this, which results in a disadvantage that the assembling operation 
becomes cumbersome. 
SUMMARY OF THE INVENTION 
The present invention has been made in view of the above problem, and an 
object of the invention is to provide a connector lock structure in which 
lock balls can be easily mounted. 
A connector lock structure of the invention comprises a tubular fitting 
portion formed on a connector housing for fitting relative to a mating 
connector; ball support holes which are formed through the tubular fitting 
portion, and are open to outer and inner peripheral surfaces of the 
tubular fitting portion; lock balls which are radially displaceably 
received respectively in the ball support holes, and are prevented from 
passing radially past that peripheral surface of the tubular fitting 
portion facing the mating connector, that portion of each of the lock 
balls, projecting from the peripheral surface of the tubular fitting 
portion, being engageable with the mating connector, thereby locking the 
two connectors in a mutually fitted condition; elastic engagement members 
each elastically displaceable radially between an engagement position 
where the elastic engagement member engages that side of the associated 
lock ball facing away from the mating connector and a retracted position 
where the associated lock ball is allowed to be disengaged from the mating 
connector; and a flexure restriction member for preventing the elastic 
engagement members from being elastically flexed into their retracted 
position. 
In the invention of this structure, when the mating connector is fitted 
relative to the tubular fitting portion, so that the lock balls are 
engaged with the mating connector, the elastic engagement members are 
prevented by the flexure restriction member from being displaced into the 
retracted position, and therefore the two connectors are locked together 
in a mutually fitted condition. When the elastic engagement members are 
displaced into their retracted position, the lock balls are displaced to 
be disengaged from the mating connector, thereby releasing the locking 
between the two connectors. 
Where the plurality of ball support holes are provided in 
circumferentially-spaced relation, the lock balls are mounted one by one 
in the respective ball support holes while elastically flexing the elastic 
engagement members into the retracted position. At this time, the mounted 
lock balls are held in the respective ball support holes by the respective 
elastic engagement members engaging the respective lock balls. 
In the invention, the elastic engagement members are movable in a direction 
of fitting of the mating connector between a lock position where the 
elastic engagement members are prevented by the flexure restriction member 
from being elastically displaced into the retracted position and a lock 
release position where the elastic engagement members are allowed to be 
displaced into the retracted position. 
In the invention of this structure, when the mating connector is fitted 
relative to the tubular fitting portion, so that the lock balls are 
engaged with the mating connector, the elastic engagement members are 
moved into the lock position, and are prevented by the flexure restriction 
member from being displaced into the retracted position, thereby locking 
the two connectors together. When the elastic engagement members are moved 
into the lock release position, the lock balls are displaced to be 
disengaged from the mating connector, thereby releasing the locking 
between the two connectors. 
Where the plurality of ball support holes are provided in 
circumferentially-spaced relation, the lock balls are mounted one by one 
in the respective ball support holes while elastically flexing the elastic 
engagement members, mounted in the lock position, into the retracted 
position. At this time, the mounted lock balls are held in the respective 
ball support holes by the elastic pushing force applied by the elastic 
engagement members. 
In the invention, each of the ball support holes is narrow and elongate in 
the direction of fitting of the mating connector, and each of the elastic 
engagement members has a ball push portion for pushing the associated lock 
ball, received in the ball support hole, toward the lock position, and the 
elastic engagement members are urged toward the lock position by a lock 
spring. 
In the invention of this structure, the mating connector, fitted relative 
to the tubular fitting portion, abuts against the lock balls, and moves 
the elastic engagement members toward the lock release position against 
the bias of the lock spring. When the elastic engagement members are 
brought out of registry with the flexure restriction member, and are 
displaced into the retracted position, the lock balls are displaced to be 
disengaged from the mating connector. Then, when the lock balls are 
engaged with the mating connector, the elastic engagement members and the 
lock balls are moved into the lock position under the influence of the 
lock spring, and the elastic engagement members are prevented from being 
displaced into the retracted position, thereby holding the two connectors 
in the locked condition. 
When mounting the lock balls in the respective ball support holes, the 
elastic engagement members are held in the lock position under the 
influence of the lock spring, and the lock balls are pushed by the 
respective ball push portions, and therefore the mounted lock balls will 
not move in the respective ball support holes, and hence will not be 
disengaged from the respective elastic engagement members. 
According to the invention as mentioned above, when mounting the lock 
balls, the mounted lock balls are held in the respective ball support 
holes by the respective elastic engagement members engaging the respective 
lock balls, and therefore even if the plurality of lock balls are arranged 
in circumferentially-spaced relation, the mounting of the lock balls can 
be carried out easily.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
One preferred embodiment of the present invention will now be described 
with reference to FIGS. 1 to 5. 
A male connector 10 (mating connector which is a constituent element of the 
present invention) includes a connector housing 11 which has a tubular 
configuration as a whole, and a male terminal 12 received in this housing. 
An engagement groove 14, having an arcuate cross-section, is formed in an 
outer peripheral surface of a forwardly-extending hood portion 13 of the 
housing over an entire circumference thereof. Lock balls 35 of a female 
connector 20 (described later) are engaged in this engagement groove 14, 
and with this arrangement the male connector 10 and the female connector 
20 can be locked together in a mutually fitted condition. 
The female connector 20 includes a connector housing 21 which has a tubular 
configuration as a whole, and a female terminal 22 received in this 
housing. The hood portion 13 of the male connector 10 is fitted in a 
forwardly-extending, tubular fitting portion 23 of the female connector, 
with its outer peripheral surface corresponding to an inner peripheral 
surface of the tubular fitting portion 23. Ball support holes 24 are 
formed through the tubular fitting portion 23 between the inner and outer 
peripheral surfaces thereof, and are disposed respectively at four 
positions circumferentially spaced 90 degrees from one another, each of 
the ball support holes 24 being elongate in the axial direction. 
With respect to the transverse cross-section of each ball support hole 24, 
those portions of opposite side surfaces of the ball support hole 24 
adjacent to an inner opening edge 24A correspond to a surface shape of a 
lock ball 35 (described later) as shown in FIG. 5, and therefore the width 
of the ball support hole 24 is reduced at the inner opening edge 24A. With 
this arrangement, the lock ball 35 is prevented from being disengaged 
radially inwardly from the ball support hole 24. The other portion of the 
ball support hole 24 than that portion thereof adjacent to the inner 
opening edge 24A has a uniform width (which is equal to the outer diameter 
of the lock ball 35) up to an outer opening edge of the ball support hole 
24. 
The lock ball 35 has a spherical shape having a diameter lager than the 
thickness of the peripheral wall of the tubular fitting portion 23, and is 
put into the ball support hole 24 from the outer side. When the lock ball 
35 is disposed most radially inwardly, part of the lock ball 35 projects 
inwardly beyond the inner periphery of the tubular fitting portion 23, and 
this projected portion is engaged in the engagement groove 14 in the male 
connector 10. 
A lock operating member 25, having a tubular shape as a whole, is fitted on 
the outer periphery of the tubular fitting portion 23 for movement in the 
axial direction (that is, in a direction of fitting with the male 
connector 10). This lock operating member 25 is urged forwardly by a lock 
spring 26, and is normally held in a forward lock position (shown in FIG. 
1) under the influence of the lock spring 26. However, the lock operating 
member 25 can be displaced into a lock release position (shown in FIG. 3) 
against the bias of the lock spring 26. 
Four elongate, elastic engagement members 27 are formed integrally with the 
lock operating member 25, and extend forwardly respectively from those 
portions of its front edge corresponding respectively to the four ball 
support holes 24. The elastic engagement members 27 are arranged radially 
outwardly of the lock balls 25, and each of the elastic engagement members 
27 can be radially elastically displaced between an engagement position 
(shown in FIG. 1) and a retracted position (shown in FIG. 2) disposed 
radially outwardly of this engagement position. When each elastic 
engagement member 27 is in the engagement position, the associated lock 
ball 35 is urged radially inwardly to project from the inner periphery of 
the tubular fitting portion 23. When each elastic engagement member 27 is 
in the retracted position, the associated lock ball 35 can be retracted 
into the ball support hole 24. A radially inwardly-projecting, ball push 
portion 28 is formed on each elastic engagement portion 27, and is 
disposed slightly rearwardly of the distal end thereof. 
A flexure restriction member 29 of a tubular shape is fixedly mounted on 
the outer peripheral surface of the tubular fitting portion 23 at the 
front end portion thereof, and extends rearwardly in an overhanging 
manner. A front portion of the flexure restriction member 29, having a 
smaller inner diameter, serves as a limiting portion 30, and a rear 
portion thereof having a larger inner diameter serves as an allowing 
portion 31. 
When the lock operating member 25 is in the lock position, the limiting 
portion 30 is in registry with the elastic engagement members 27, and the 
inner diameter of the limiting portion 30 is equal to a circle on which 
the outer surfaces of the elastic engagement members 27 lie. Therefore, 
when the lock operating member 25 is in the lock position, with the 
elastic engagement members 27 disposed in their engagement position, the 
limiting portion 30 prevents the elastic engagement members 27 from being 
displaced into their retracted position. 
When the lock operating member 25 is in the lock release position, the 
allowing portion 31 is in registry with the elastic engagement members 27, 
and in this condition the elastic engagement members 27 can be elastically 
displaced into their retracted position. 
A rear end of the flexure restriction member 29 serves as a stopper 32, and 
this stopper 32 prevents the lock operating member 25 from moving 
forwardly beyond the lock position. 
Next, the operation of this embodiment will now be described. 
When the female connector 20 is to be connected, the lock operating member 
25 and the lock spring 26 are mounted on the outer periphery of the 
tubular fitting portion 23. In this condition, the lock operating member 
25 is held in the lock position, and the front end portions of the ball 
support holes 24 are covered respectively with the elastic engagement 
members 27 disposed radially outwardly thereof. Then, in this condition, 
the elastic engagement members 27 are elastically displaced radially 
outwardly one by one, and the lock balls 35 are put in the respective ball 
support holes 24 one by one. At this time, the precedingly-mounted lock 
ball 35 is held in the front end portion of the ball support hole 24 by 
the elastic engagement member 27 and the ball push portion 28, and 
therefore even if the posture of the female connector 20 is changed, the 
lock ball 35 will not be disengaged from the ball support hole 24. 
Therefore, the mounting of the lock balls 35 can be carried out easily. 
When the male connector 10 begins to fit in the female connector 20, the 
outer front edge of the hood portion 13 of the male connector 10 abuts 
against the lock balls 35, projecting radially inwardly from the inner 
periphery of the tubular fitting portion 23, and presses these lock balls 
35. However, the lock balls 35 are urged radially inwardly by the 
respective elastic engagement members 27 prevented by the limiting portion 
30 from radially-outward displacement, and therefore the lock balls 35 and 
the lock operating member 25 are pushed back in unison against the bias of 
the lock spring 26. 
Then, when the elastic engagement members 27 are shifted from the region, 
corresponding to the limiting portion 30, to the region corresponding to 
the allowing portion 31, the rearward movement of the lock operating 
member 25 is stopped, and the elastic engagement members 27 are 
elastically deformed radially outwardly, and the lock balls 35 are 
retracted into the respective ball support holes 24 (see FIG. 2). 
Thereafter, the two connectors 10 and 20 are fitted together, with the 
outer peripheral surface of the hood portion 13 held in contact with the 
lock balls 35. 
Then, the two connectors 10 and 20 are fitted deep together, and the 
engagement groove 14 in the male connector 10 is brought into registry 
with the lock balls 35 whereupon the elastic engagement members 27 are 
elastically restored radially inwardly because of their elastic restoring 
force, and the lock balls 35 become engaged in the engagement groove 14. 
As a result, under the influence of the lock spring 26, the lock operating 
member 25 is moved forward, and also the male connector 10 is moved 
rearward relative to the female connector, and the fitting operation is 
completed when the lock operating member 25 reaches the lock position. At 
this time, since the elastic engagement members 27 are disposed in 
registry with the limiting portion 30, and therefore are prevented from 
being displaced radially outwardly, the engagement of the lock balls 35 in 
the engagement groove 14 is maintained, so that the fitted two connectors 
10 and 20 are locked together against withdrawal. 
For disengaging the two connectors 10 and 20 from each other, the lock 
operating member 25 is moved from the lock position into the lock release 
position, so that the elastic engagement members 27 are shifted from the 
limiting portion 30 to the allowing portion 31, thereby releasing the 
locking. Then, in this condition, the lock operating member 25 is held in 
the lock release position with the hand, and the two connectors 10 and 20 
are moved away from each other. As a result, the lock balls 35 are 
displaced radially outwardly to be disengaged from the engagement groove 
14, and the two connectors 10 and 20 are disengaged from each other 
through the process shown in FIG. 3. 
As described above, even if the posture of the female connector 20 is 
changed when the female connector 20 is to be connected, the 
already-mounted lock ball or balls 35 are held in the respective ball 
support holes 24 by the respective elastic engagement members 27, and 
therefore though the lock balls 35 are arranged respectively in the four 
positions circumferentially spaced from one another, the mounting of the 
lock balls can be carried out easily. 
The present invention is not to be limited to the above description and the 
drawings, and for example, the following embodiments fall within the scope 
of the present invention. Further, other modifications than the following 
can be made without departing from the scope of the invention. 
In the above embodiment, although the elastic engagement members are 
engaged with the mating connector from the outer periphery side, there may 
be provided such a structure that elastic engagement members are engaged 
with the mating connector from the inner periphery side. 
In the above embodiment, although there is provided the lock spring, the 
provision of the lock spring may be omitted, in which case the lock 
operating member is moved manually. 
In the above embodiment, although the flexure restriction member is fixed 
while the lock operating member is movable, there may be provided such a 
structure that the lock operating member is fixed while the flexure 
restriction member is movable.