1. A ball screw apparatus, comprising:
a screw shaft having a screw groove in a spiral shape at an outer peripheral face thereof;
a nut having a screw groove in a spiral shape in correspondence with the screw groove of the screw shaft at an inner peripheral face thereof and screwed to the screw shaft, the nut having holes formed at an outer peripheral portion thereof;
a number of balls rollably charged into a rolling passage that is defined by the screw groove of the screw shaft and the screw groove of the nut; and
a ball circulating member formed substantially in a U-like shape and having end portions to be fitted to the holes to infinitely circulate the balls by scooping up the balls rolling on the rolling passage at a middle thereof and returning the balls to the rolling passage;
wherein the ball circulating member comprises a side cap which includes leg portions at both end portions thereof to be fitted into the holes, each of the leg portions containing at least one of a scooping up path for scooping up the balls and a returning path for returning the balls, the scooping up path and the retuning path being inclined with respect to respective outer peripheral faces of the leg portions;
the holes include a slot substantially in parallel with directions of the screw grooves of the screw shaft and the nut; and
the scooping up path and the returning path are directed substantially in a tangential direction of the screw shaft and inclined substantially toward a lead angle direction of the screw grooves of the screw shaft and the nut.
2. The ball screw apparatus according to claim 1,
wherein a sidewall of the slot is used as a portion of a path for circulating the ball.
3. The ball screw apparatus according to claim 2,
wherein a width dimension of the slot substantially the same as a diameter of the scooping up path and the returning path at a vicinity of a scoop up point where the balls are separated from the screw groove of the screw shaft.
4. The ball screw apparatus according to claim 1,
wherein an apparent scoop up angle is set from 20\xb0 to 45\xb0, wherein the apparent scoop up angle is an angle of scooping up the balls viewed in an axis direction of the, screw shaft at a scoop up point where the balls are separated from the screw groove of the screw shaft.
5. A ball screw, comprising:
a screw shaft having a ball screw groove formed on an outer peripheral face thereof;
a nut having a ball screw groove formed on an inner peripheral face thereof so as to be opposed to the ball screw groove of the screw shaft;
a number of balls provided between the ball screw groove of the screw shaft and the ball screw groove of the nut; and
a ball circulating member made of a resin for circulating the balls rolling between the ball screw grooves of the screw shaft and the nut in accordance with a rotational movement of the screw shaft or the nut at an exterior of the nut;
wherein the ball circulating member includes:
a tongue portion for scooping up the ball rolling between the ball screw grooves of the screw shaft and the nut in a direction of a tangential line that is in contact with a center track circle of the balls,
a ball return path for circulating the ball, and
a pair of return path inlet and outlet forming portions for forming inlet and outlet portions of the ball return path;
the nut includes a circulating member inserting hole fitted to the return path inlet and outlet forming portion; and
a circulating member inserting hole is formed in an oval shape that is longitudinal along a longitudinal direction of the ball screw groove; and
a thickness of the tongue portion along a length direction of the ball screw groove is equal to or larger than \xbd of a diameter of the ball.
6. The ball screw according to claim 5,
wherein a shape of the tongue portion is formed substantially the same as a shape of the ball screw groove of the screw shaft.
7. The ball screw according to claim 5,
wherein an angle of intersecting a straight line passing a point of scooping up a ball scooped up from the screw groove of the screw shaft and a center of the screw shaft with a center line of the circulating member inserting hole is made to be 45\xb0 through 80\xb0.
8. The ball screw according to claim 5,
wherein the ball return path includes linear path portions having a length equal to or larger than \xbd of the diameter of the ball at both end portions thereof.
9. A ball screw, comprising:
a screw shaft having a first screw groove in a spiral shape at an outer peripheral face thereof;
a nut having a second screw groove in a spiral shape at an inner peripheral face thereof in correspondence with the first screw groove and screwed to the screw shaft, the nut having slots;
a plurality of balls rollably provided into a rolling passage that is defined between the first screw groove and the second screw groove; and
a side cap having leg portions to be fitted into the slots to infinitely circulate the balls by scooping up the balls rolling on the rolling passage at a middle thereof and returning the balls to the rolling passage;
wherein the slots are longitudinal in a direction inclined toward an apparent scoop up angle so that a longitudinal direction of each of the slots is substantially equal to a tangent scooping up direction, wherein the apparent scoop up angle is an angle of scooping up the balls viewed in an axis direction of the screw shaft at a scoop up point where the balls are separated from the first screw groove; and
the apparent scoop up angle is set from 20\xb0 to 45\xb0.
10. The ball screw according to claim 9,
wherein the side cap includes a circulating path for circulating the balls, and a tongue portion for guiding the balls from the rolling passage to the circulating path;
the tongue portion extends in a direction substantially equal to the longitudinal direction of at least one of the slots; and
the tongue portion has a length equal to or more than a half of a diameter of each of the balls.
11. The ball screw according to claim 9,
wherein the side cap has a linear portion extending from the scoop up point toward the circulating path; and
the linear portion has a length equal to or more than a half of a diameter of each of the balls.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An image processing apparatus, comprising:
an input device configured to receive image data of a given data size and transmit the image data in N data blocks, with N representing a first given number;
an encoder configured to encode the N data blocks transmitted from the input unit;
a memory configured to store the N data blocks encoded by the encoder;
a first allocator configured to allocate, before encoding, N memory areas of a specified memory size within the memory;
a data block size determination mechanism configured to determine whether each of the N data blocks is larger than the memory size;
a second allocator configured to dynamically allocate an additional memory area within the memory when the determination mechanism determines that one of the N data blocks is larger than the memory size; and
a processor configured to retrieve the image data from the memory for processing thereof.
2. The image processing apparatus according to claim 1, wherein the N data blocks are sequentially stored in the memory, the determination mechanism determines that one of the N data blocks is larger than the memory size when a first count is different from a second count, and the second allocator calculates a difference between the first count and the second count to dynamically allocate M additional memory areas,
the first count representing a number of data blocks stored in the memory and the second count representing a number of memory areas consumed by the stored data blocks, M representing a number corresponding to the calculated difference.
3. The image processing apparatus according to claim 1, wherein the first allocator specifies, as the memory size, a first size and a second size based on a given compression ratio, the first given number N, and the given data size to allocate N\u22122 compression areas and two non-compression areas, with the N data blocks sequentially stored first in the N\u22122 compression areas and then in the two non-compression areas,
the first size being an expected size of one data block compressed by the given compression ratio and the second size being an uncompressed size of one data block,
the compression area being a memory area of the first size and the non-compression area being a memory area of the second size.
4. The image processing apparatus according to claim 1, further comprising an interrupt generator configured to generate an interrupt indicating that each of the N data blocks is input to be stored,
wherein the determination mechanism determines whether each of the N data blocks is larger than the memory size in response to each interrupt.
5. The image processing apparatus according to claim 2, further comprising an interrupt generator configured to generate an interrupt indicating that each of the N data blocks is input to be stored,
wherein the determination mechanism determines whether each of the N data blocks is larger than the memory size in response to each interrupt.
6. The image processing apparatus according to claim 2, further comprising an interrupt generator configured to generate an interrupt indicating that each of the N data blocks is input to be stored,
wherein the determination mechanism determines whether each of the N data blocks is larger than the memory size after a given second number of data blocks are stored in the memory.
7. The image processing apparatus according to claim 3, wherein the second allocator assigns one non-compression area when dynamically allocating one additional memory area, and assigns two non-compression areas and M\u22122 compression areas when dynamically allocating M additional memory areas, with M representing a number equal to or larger than 2.
8. The image processing apparatus according to claim 3, wherein each of the non-compression areas is divided into a sequence of segments of a third size, each of the sequence of segments capable of serving as one memory area, and the N data blocks are sequentially stored first in the N\u22122 compression areas and then in the sequence of segments within the two non-compression areas.
9. The image processing apparatus according to claim 8, wherein the third size is determined to be equal to the first size.
10. An image processing method, comprising:
inputting image data of a given data size transmitted in N data blocks, with N representing a first given number;
encoding the N-data blocks;
allocating, before the encoding, N memory areas within a memory;
storing the encoded N data blocks in the memory;
determining whether each of the N data blocks is larger than a specified memory size;
dynamically allocating an additional memory area within the memory when determining that one of the N data blocks is larger than the memory size; and
retrieving the image data from the memory for processing thereof.
11. The method of claim 10, wherein the N data blocks are sequentially stored in the memory, one of the N data blocks is determined to be larger than the memory size when a first count is different from a second count, and a difference between the first count and the second count is calculated to dynamically allocate M additional memory areas,
the first count representing a number of data blocks stored in the memory and the second count representing a number of memory areas consumed by the stored data blocks,
M representing a number corresponding to the calculated difference.
12. The method of claim 10, wherein a first size and a second size are specified as the memory size based on a given compression ratio, the first given number N, and the given data size to allocate N\u22122 compression areas and two non-compression areas, with the N data blocks sequentially stored first in the N\u22122 compression areas and then in the two non-compression areas,
the first size being an expected size of one data block compressed by the given compression ratio and the second size being an uncompressed size of one data block,
the compression area being a memory area of the first size and the non-compression area being a memory area of the second size.
13. The method of claim 10, further comprising generating an interrupt indicating that each of the N data blocks is input to be stored,
wherein whether each of the N data blocks is larger than the memory size is determined in response to each interrupt.
14. The method of claim 11, further comprising generating an interrupt indicating that each of the N data blocks is input to be stored,
wherein whether each of the N data blocks is larger than the memory size is determined in response to each interrupt.
15. The method of claim 11, further comprising generating an interrupt indicating that each of the N data blocks is input to be stored,
wherein whether each of the N data blocks is larger than the memory size is determined after a given second number of data blocks are stored in the memory.
16. The method of claim 12, wherein one non-compression area is assigned when dynamically allocating one additional memory area, and two non-compression areas and M\u22122 compression areas are assigned when dynamically allocating M additional memory areas,
M representing a number equal to or larger than 2.
17. The method of claim 12, wherein each of the non-compression areas is divided into a sequence of segments of a third size, each of the sequence of segments capable of serving as one memory area, and the N data blocks are sequentially stored first in the N\u22122 compression areas and then in the sequence of segments within the two non-compression areas.
18. The method of claim 17, wherein the third size is determined to be equal to the first size.
19. A program for causing a computer to perform an image processing method, the image processing method comprising:
inputting image data of a given data size transmitted in N data blocks, with N representing a first given number;
encoding the N data blocks;
allocating, before the encoding, N memory areas within a memory;
storing the encoded N data blocks in the memory;
determining whether each of the N data blocks is larger than a specified memory size;
dynamically allocating an additional memory area within the memory when determining that one of the N data blocks is larger than the memory size; and
retrieving the image data from the memory for processing thereof.