Sewing machine

A sewing machine comprising:

• a plurality of sewing units, each of which includes:
• thread take-up lever formed in a swayable manner;
• a needle thread control section that is disposed at an upstream position in a needle thread path of the thread take-up lever, that controls tension on a needle thread, and that includes
• an upstream grip section including
• an upstream grip section main body which grips a needle thread in a pinching manner and
• an upstream actuation section that performs, with respect to the upstream grip section main body, switching between a closed state in which the needle thread is gripped and an open state in which the needle thread is released from a gripped state,
• a downstream grip section that is disposed at a downstream position in the needle thread path of the upstream grip section and that has
• a downstream grip section main body which grips a needle thread in a pinching manner and
• a downstream actuation section that performs, with respect to the downstream grip section main body, switching between a closed state in which the needle thread is gripped and an open state in which the needle thread is released from a gripped state, and
• a turning section that turns the needle thread between the upstream grip section main body and the downstream grip section main body and that has
• a turning arm which contacts the needle thread and
• a needle thread motor which turns the turning arm;
• an outer shuttle which has a guide groove formed in a circular-arc inner peripheral surface;
• a middle shuttle which rotates along the guide groove of the outer shuttle, which retains the needle thread, at least a rear section and a shaft of which are formed from a non-magnetic substance, and which has
• a race section that is formed along a peripheral edge of the middle shuttle in the form of a circular arc and which is supported so as to be slidable over the guide groove,
• a rear section continually extending from an end of a rear-side, that is one side with respect to an axial direction, in an inner circumferential edge of the race, and
• the shaft which is formed on a front side of the rear section and which is formed along a rotating center of the rear section;
• a bobbin which has a hole into which the shaft of the middle shuttle is inserted, which is axially supported within the middle shuttle as a result of the shaft being inserted into the hole, and which has
• a first magnet section that is provided on a rear side surface which is a surface opposing a rear section of the middle shuttle when the bobbin is axially supported by the shaft;
• and
• a bobbin thread control section which has
• a bobbin thread motor which is provided at the rear side of the middle shuttle and has a rotary shaft coaxial to the rotating center of the middle shuttle and which rotates the rotary shaft in a direction opposite to a direction in which the bobbin rotates on occasions of a bobbin thread wound around the bobbin being withdrawn, and
• a second magnet section which is rotated by the bobbin thread motor and provided in close proximity to the rear section of the middle shuttle and which rotates the first magnet section;
• a storage section for storing a torque table that specifies a needle thread control torque value and a bobbin thread control torque value which correspond to a combination of a value of a stitch width and a value based on a stitching direction;
• and
• a control section that detects, according to the torque table, a needle thread control torque value and a bobbin thread control torque value for each stitch in the embroidery data which store, for each stitch, data pertinent to a value of a stitch width and data pertinent to a value representing a stitching direction, thereby generating needle thread control torque data which store, for each stitch, a needle thread control torque value and bobbin thread control torque data which stored, for each stitch, a bobbin thread control torque value;
• that, when performing embroidery sewing according to embroidery data and in connection with the needle thread, in a control zone for each stitch, controls the needle thread motor in each of the sewing units in accordance with a torque value of the needle thread control torque data while closing the upstream grip section main body and while opening the downstream grip section main body such that tension is imparted to the needle thread against a direction in which the thread take-up lever draws the needle thread, thereby imparting rotating force to a turning arm, within a control zone;
• namely, within a needle thread torque control zone which is a zone including at least a portion of a zone from one dead point to another dead point of the thread take-up lever during which the thread take-up lever draws the needle thread with respect to processed fabric to be sewn with the needle thread;
• that controls the needle thread motor in each of the sewing units in accordance with position data pertinent to a needle thread motor angle such that an angle of the needle thread motor, which is a position of the needle thread motor in a rotating direction, returns to an initial angular position of the needle thread motor, while opening the upstream grip section main body and closing the downstream grip section main body, within a position control zone which is at least a portion of a zone other than the torque control zone, thereby imparting rotating force to the turning arm to draw the needle thread from an upstream position;
• and that, in connection with the bobbin thread, controls the bobbin thread motor in each of the sewing units in accordance with a torque value of the bobbin thread control torque data, within a bobbin thread torque control zone which is at least a portion of a zone from the one dead point to the another dead point of the thread take-up lever.