Mechanical main shaft with double-layer output shaft

Abstract

The utility model discloses a mechanical main shaft with a double-layer output shaft, which comprises a main shaft body, the main shaft body comprises a shell, a front cover and a rear cover, the front cover and the rear cover are arranged at the front end and the rear end of the shell, a hollow outer rotating shaft is rotatably arranged in the shell, an inner rotating shaft is arranged in the outer rotating shaft, and a sliding sleeve is sleeved between the two ends of the outer rotating shaft and the two ends of the inner rotating shaft. Torsion is transmitted between the outer rotating shaft and the inner rotating shaft through keys and key grooves. Grinding tools can be mounted at the front ends of the inner rotating shaft and the outer rotating shaft, and a power transmission part sleeves the outer wall of the rear end of the outer rotating shaft and is used for transmitting force to the outer rotating shaft; the device further comprises a magnetic coupling feeding mechanism. Grinding tools can be installed, the space utilization rate of a machine can be effectively improved, more grinding heads can be integrated on machine equipment, the machine equipment is shortened, and cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to mechanical spindle technical field, concretely relates to a mechanical spindle with double -layer output shaft. BACKGROUND

[0002] Mechanical spindle is the core component in mechanical equipment for power transmission, support rotating parts and realize precision motion, commonly used in machine tool, machining center, lathe and other equipment. Its core function includes: 1. power transmission, through motor drive spindle rotation, drive tool or workpiece motion;2. precision support, through bearing system (such as angular contact ball bearing, static pressure bearing) ensure the stability and precision under high speed;3. processing execution, directly participate in cutting, grinding and other machining process, its performance directly influences the machining quality.

[0003] According to application scene and structure, mechanical spindle can be divided into the following categories: 1. ordinary spindle: for traditional machine tool, the speed is lower (usually <10,000 rpm), the carrying capacity is strong, but the precision is relatively low. 2. high-speed electric spindle: integrated motor and spindle, the speed can reach tens of thousands of revolutions per minute (such as 50,000 rpm), used for precision machining (such as PCB drilling).

[0004] The mechanical spindle on the market currently only has one output size and form, relatively fixed, in some specific environment, the processing surface needs to be polished and polished, or some non-standard action combination machine tool, often needs multiple spindles to cooperate, the mechanical space utilization rate is low, the machine size cannot be compressed;The manufacturing cost is large, and the machine rigidity is poor.

[0005] In the field of mechanical processing and precision manufacturing, the axial feed mechanism of the spindle is the core module that determines the compactness, dynamic response and cost-effectiveness of the equipment. The traditional mechanical spindle or electric spindle feed scheme mainly uses drag plate screw rod mechanism or bearing transition connection structure, and the technical framework has the following systematic bottlenecks: 1. mechanical redundancy and space inefficiency: the drag plate screw rod needs to be nested with multiple guide rails and support components, the axial length is redundant (usually accounts for 30%-50% of the total spindle length), resulting in bulky machine size;Although the bearing transition structure can alleviate the rigid impact, it needs to configure additional couplings, flanges and other connecting parts, further occupying mechanical space. 2. Dynamic performance is limited: the friction loss and backlash of the screw rod transmission are significant, and the crawling phenomenon (the precision loss under critical speed is ±5 μm) is easy to occur at high speed, and the lubrication is highly dependent, and the high temperature working condition is easy to jam;The elastic deformation of the bearing transition mechanism will introduce phase delay, affecting the real-time performance of micron-level feeding. 3. Cost and adaptability contradiction: the manufacturing cost of high-precision ball screw and customized bearing assembly accounts for up to 40%, but its driving source is only suitable for rotary motor or hydraulic motor, which is difficult to be compatible with pneumatic, linear motor and other new power forms, which restricts the modular expansion capability of the equipment. UTILITY MODEL CONTENT

[0006] In order to at least overcome one of the technical problems existing in the prior art, the utility model provides a mechanical spindle with double-layer output shafts, which has an outer rotating shaft and an inner rotating shaft with the same rotating speed and rotating direction, and both can be installed with grinding tools, effectively improving the space utilization of the machine, integrating more grinding heads, shortening the machine equipment and reducing the cost.

[0007] A kind of mechanical spindle with double-layer output shafts, including spindle body, it includes shell, front cover and rear cover installed at the front and rear ends of shell, hollow outer rotating shaft is rotatably installed in shell, inner rotating shaft is installed in outer rotating shaft, sliding sleeve is set between the two ends of outer rotating shaft and inner rotating shaft, torque is transmitted between outer rotating shaft and inner rotating shaft by key and keyway, inner rotating shaft can rotate synchronously and move axially;The front end of inner rotating shaft and outer rotating shaft can be installed with grinding tools, power transmission component is set on the rear end outer wall of outer rotating shaft for transmitting force to outer rotating shaft;It further includes magnetic coupling feed mechanism, which includes: feed shaft coaxially arranged beside inner rotating shaft, ball groove is formed on the end face of inner rotating shaft and feed shaft close to each other, ball is placed in ball groove;The outer wall of inner rotating shaft and feed shaft close to end is sleeved with gland, two glands keep non-contact state;Ball hole is formed on the gland, and the position of ball hole corresponds to ball groove, the ball is limited in the area between ball groove and ball hole by gland, and part of the outer wall of two balls protrudes outside ball hole and contacts each other;One magnetic steel with opposite magnetic polarity is installed on the end of each of the two glands close to each other, and the two magnetic steels keep non-contact state.

[0008] In some embodiments, the outer wall of the end close to the inner rotating shaft and the feed shaft is provided with a screw thread for threaded connection with the gland;At least one fastener is installed on the outer wall of the gland, and the fastener fixes the gland with the inner rotating shaft and the feed shaft respectively along the radial direction.

[0009] In some embodiments, the magnetic steel is in the shape of a circular ring, the end faces of the two glands are provided with axially protruding positioning shafts, and the magnetic steel is sleeved on the positioning shafts;At least two regular distribution locking members are further included, and the locking members fix the magnetic steel with the inner rotating shaft and the feed shaft respectively along the axial direction.

[0010] In some embodiments, the ball groove is in the shape of a round nest, the ball is made of quenched alloy steel, and the magnetic steel is a neodymium-iron-boron permanent magnet.

[0011] In some embodiments, an axially telescopic sealing sleeve is installed between the front ends of outer rotating shaft and inner rotating shaft, the two ends of the sealing sleeve are limited on the outer walls of outer rotating shaft and inner rotating shaft by fastening ring, and outer rotating shaft, inner rotating shaft and sealing sleeve are rotatably connected.

[0012] In some embodiments, the power transmission component is a belt pulley, and a belt replacement window is formed on the rear cover.

[0013] In some embodiments, a cylinder is installed on the rear end surface of the rear cover for driving the feed shaft to move forward and backward along the axial direction.

[0014] In some embodiments, the key and the keyway include a plurality of splines uniformly distributed along the axial direction, and a plurality of keyways adapted to the splines.

[0015] Additional aspects and advantages of the present application will be further described in the following description, some of which will be apparent from the description, or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a perspective structural schematic diagram of the present application;

[0018] Figure 2 is a front structural schematic diagram of the present application;

[0019] Figure 3 is a cross-sectional structural schematic diagram of the present application;

[0020] Figure 4 is an enlarged view of A in Figure 3

[0021] Figure 5 is a front structural schematic diagram of the magnetic coupling feeding mechanism;

[0022] Figure 6 Figure 5 is a cross-sectional structural schematic diagram of the magnetic coupling feeding mechanism;

[0023] Figure 7 is a perspective structural schematic diagram of the magnetic coupling feeding mechanism.

[0024] LIST OF REFERENCE NUMERALS:

[0025] Main shaft body 1, outer shell 1-1, front cover 1-2, rear cover 1-3;

[0026] Outer rotating shaft 2, inner rotating shaft 3, sliding sleeve 4, key 5, keyway 6, grinding tool 7,

[0027] Power transmission component 8;

[0028] Magnetic coupling feeding mechanism 9, feed shaft 9-1, ball groove 9-2, ball 9-3,

[0029] Gland 9-4, ball hole 9-5, magnetic steel 9-6;

[0030] Thread 10, fastener 11, positioning shaft 12, locking member 13, sealing sleeve 14,​

[0031] Fastening ring 15, belt replacement window 16, air cylinder 17. DETAILED DESCRIPTION

[0032] The embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only, for the purpose of explaining the present application, and should not be understood as a limitation to the present application.

[0033] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation to the present application.

[0034] In the description of the present application, the meaning of "several" is one or more, and the meaning of "multiple" is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of indicated technical features.

[0035] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] Reference Figures 1-7The utility model provides a kind of mechanical spindle with double-layer output shaft, including spindle body 1, it includes shell 1-1, front cover 1-2 and rear cover 1-3 are installed in the front and rear both ends of shell 1-1, hollow outer rotating shaft 2 is rotatably installed in shell 1-1, inner rotating shaft 3 is installed in outer rotating shaft 2, sliding sleeve 4 is sleeved between the both ends of outer rotating shaft 2 and inner rotating shaft 3, preferably copper sleeve;Torsion is transmitted between outer rotating shaft 2 and inner rotating shaft 3 by key 5 and key groove 6, inner rotating shaft 3 can rotate and axially move synchronously;The front end of inner rotating shaft 3 and outer rotating shaft 2 can be installed grinding tool 7, it can be abrasive wheel, polishing wheel, milling cutter, turning tool etc., and be connected and fixed by abrasive wheel seat or tool holder;The rear end outer wall of outer rotating shaft 2 is sleeved with power transmission component 8, for transmitting force to outer rotating shaft 2;It further includes magnetic coupling feed mechanism 9, which comprises: feed shaft 9-1 is coaxially arranged beside inner rotating shaft 3, ball groove 9-2 is formed on the end face of inner rotating shaft 3 and feed shaft 9-1 close to each other, ball 9-3 is placed in ball groove 9-2;Compression gland 9-4 is sleeved on the outer wall of inner rotating shaft 3 and feed shaft 9-1 close to end, two compression glands 9-4 keep non-contact state;Ball hole 9-5 is formed on compression gland 9-4 and penetrates along the axial direction, ball hole 9-5 corresponds to the position of ball groove 9-2, compression gland 9-4 limits ball 9-3 between ball groove 9-2 and ball hole 9-5, and the partial outer wall of two balls 9-3 protrudes to the outside of ball hole 9-5 and contacts each other;One magnetic steel 9-6 with opposite magnetic polarity is installed on the end of each two compression glands 9-4 close to each other, and the two magnetic steels 9-6 keep non-contact state.

[0037] The core innovation of the mechanical spindle includes the synergistic effect of the double-layer rotating shaft structure and the magnetic coupling feed mechanism, and the working principle is as follows:

[0038] 1. Power transmission and synchronous rotation

[0039] Outer rotating shaft 2: receive external power through rear end power transmission component 8 (such as belt pulley, gear), drive outer rotating shaft 2 to rotate;

[0040] Inner rotating shaft 3: rotate synchronously with outer rotating shaft 2 through key 5 and key groove 6, but can axially slide, sliding sleeve 4 reduces friction;

[0041] Tool installation: inner and outer rotating shaft front end can independently install grinding tool 7, realize double-tool synchronous processing or composite processing.

[0042] 2. Axial control of magnetic coupling feed mechanism 9:

[0043] Ball transmission: two balls 9-3 roll in contact under the limitation of ball groove 9-2 and ball hole 9-5, transmit rotary motion while allowing axial displacement;

[0044] Magnetic drive: heteropolar magnetic steel 9-6 generates attractive force, when the feed shaft 9-1 moves axially, the magnetic force pulls the inner rotating shaft 3 to move synchronously, realizing non-contact force transmission and avoiding mechanical wear.

[0045] 3. The cooperation of the sliding sleeve and the key groove:

[0046] The sliding sleeve 4 (copper sleeve) reduces the friction resistance of the axial movement of the inner rotating shaft 3, and the key 5 and the key groove 6 ensure that the torque transmission does not fail.

[0047] The technical problem solved by the present application is:

[0048] 1. Precision problem of double-tool cooperative machining: it is difficult for traditional spindles to realize synchronous rotation of inner and outer shafts and independent axial feeding, the present scheme ensures the synchronous rotation of the inner rotating shaft during feeding through magnetic coupling and spherical transmission, avoiding machining errors.

[0049] 2. Wear and service life of axial feeding: mechanical feeding mechanism (such as screw) is easy to wear, non-contact transmission of magnetic coupling reduces friction and prolongs service life.

[0050] 3. Compactness and multifunctionality: double-layer shaft design integrates two tools (such as rough grinding + fine grinding), saving space; the layout of magnetic steel and ball optimizes the axial size, adapting to narrow machining environment.

[0051] 4. Dynamic balance stability: the combined design of the sliding sleeve 4 and the key groove 6 avoids the radial runout of the inner rotating shaft 3 during high-speed rotation, improving the dynamic balance performance.

[0052] In some embodiments, the inner rotating shaft 3 and the outer wall of the feed shaft 9-1 near the end are provided with a screw thread 10 for threaded connection with the gland 9-4; at least one fastener 11 is installed on the outer wall of the gland 9-4, preferably two symmetrically arranged, the fastener 11 fixes the gland 9-4 with the inner rotating shaft 3 and the feed shaft 9-1 respectively in the radial direction; the screw thread 10 realizes the axial pre-tightening of the gland 9-4 with the inner rotating shaft 3 / feed shaft 9-1, ensuring the initial positioning accuracy; the fastener 11 (such as a top screw) applies radial pressure, eliminates the gap of threaded connection, and resists loosening caused by centrifugal force.

[0053] In some embodiments, the magnet 9-6 is in the shape of a ring, and the end faces of the two pressure caps 9-4 are provided with axially protruding positioning shafts 12, on which the magnet 9-6 is sleeved; it also includes at least two regularly distributed locking members 13, preferably three evenly distributed, the locking members 13 fixing the magnet 9-6 to the inner rotating shaft 3 and the feed shaft 9-1 respectively along the axial direction; the axial protrusion design of the positioning shaft 12 ensures the coaxiality of the magnet 9-6 and the pressure caps 9-4, avoiding the skewing of the magnetic lines of force; after the ring magnet 9-6 is sleeved, its inner diameter forms a transition fit with the positioning shaft 12, taking into account both installation convenience and positioning accuracy; at least two locking members 13 (such as M3 socket head cap screws) are evenly distributed 120° along the circumference, and the centrifugal effect of the magnet 9-6 is counteracted by the axial preload.

[0054] In some embodiments, the ball groove 9-2 is a circular cavity that can match the shape of the ball 9-3; the ball 9-3 is made of quenched alloy steel, providing ultra-high wear resistance and friction coefficient; the magnet 9-6 is a neodymium iron boron permanent magnet with high magnetic field strength, which transmits axial thrust through non-contact magnetic repulsion.

[0055] In some embodiments, an axially expandable sealing sleeve 14 is installed between the front ends of the outer shaft 2 and the inner shaft 3. The two ends of the sealing sleeve 14 are limited to the outer walls of the outer shaft 2 and the inner shaft 3 by fastening rings 15. The outer shaft, the inner shaft and the sealing sleeve are rotatably connected. The axial pre-compression of the sealing sleeve 14 is 8%-12% of the total length, and the axial tension is maintained by elastic restoring force. The sealing sleeve 14 is made of bellows or elastic polymer material (such as fluororubber) to maintain sealing when the inner shaft 3 moves axially. The fastening rings 15 (such as stainless steel hose clamps) limit the two ends of the sealing sleeve 14 on the stepped shaft of the outer shaft 2 and the inner shaft 3 to form an IP67 dustproof and waterproof rating. When the inner shaft 3 moves axially, the sealing sleeve 14 absorbs the displacement through expansion and contraction deformation, while preventing cutting fluid / metal chips from entering the shaft system.

[0056] In some embodiments, the power transmission component 8 is a pulley, and a belt replacement window 16 is provided on the rear cover 1-3; the pulley transmits the motor power to the outer shaft 2 through a multi-ribbed belt (such as PK type) or a synchronous belt (such as HTD8M), which has high transmission efficiency; the belt replacement window 16 is a rectangular opening, which can be completed without removing the rear cover 1-3.

[0057] In some embodiments, a cylinder 17 is installed on the rear end face of the rear cover 1-3 for driving the feed shaft 9-1 to move back and forth axially; the cylinder 17 can also be replaced by a manual screw, hydraulic cylinder or motor, etc.

[0058] In some embodiments, the key 5 and keyway 6 include a plurality of splines evenly distributed along the axial direction and a plurality of keyways adapted to the splines. The plurality of splines 5-1 distributed along the axial direction mesh with the keyways 6-1 simultaneously, uniformly transmitting the torque of the outer rotating shaft 2 to the inner rotating shaft 3, thereby increasing the contact area; the fit clearance between the splines 5-1 and the keyways 6-1 allows the inner rotating shaft 3 to move axially while maintaining rotational synchronization accuracy.

[0059] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A mechanical spindle with double layer output shaft, comprising a spindle body which comprises a housing, a front cover and a rear cover mounted at the front and rear ends of the housing, characterized in that: The hollow outer rotating shaft is rotatably installed in the shell, the inner rotating shaft is installed in the outer rotating shaft, the sliding sleeve is sleeved between the two ends of the outer rotating shaft and the inner rotating shaft, the torsion is transmitted between the outer rotating shaft and the inner rotating shaft through the key and the keyway, the inner rotating shaft can rotate synchronously and move axially; the front ends of the inner rotating shaft and the outer rotating shaft can be installed with grinding tools, the power transmission component is sleeved on the rear end outer wall of the outer rotating shaft for transmitting force to the outer rotating shaft; the magnetic coupling feeding mechanism comprises: the feeding shaft coaxially arranged beside the inner rotating shaft, the ball grooves are correspondingly formed on the end faces of the inner rotating shaft and the feeding shaft close to each other, and the balls are placed in the ball grooves; the compression covers are sleeved on the outer walls of the inner rotating shaft and the feeding shaft close to the end, and the two compression covers are kept in a non-contact state; the ball holes are formed in the compression covers and penetrate in the axial direction, the ball holes correspond to the positions of the ball grooves, the compression cover limits the balls in the area between the ball grooves and the ball holes, and part of the outer walls of the two balls protrude out of the ball holes and contact each other; the magnetic steels with opposite magnetic polarities are respectively installed on the ends of the two compression covers close to each other, and the two magnetic steels are kept in a non-contact state.

2. The mechanical spindle with a dual layer output shaft as claimed in claim 1, characterized in that: Screw threads are arranged on the outer walls of the inner rotating shaft and the feeding shaft close to the end for threadedly connecting with the compression covers; at least one fastener is installed on the outer wall of the compression cover, and the fastener fixes the compression cover with the inner rotating shaft and the feeding shaft respectively along the radial direction.

3. The mechanical spindle with a dual layer output shaft as claimed in claim 2, characterized in that: The magnetic steel is in the shape of a circular ring, the positioning shafts protruding in the axial direction are arranged on the end faces of the two compression covers, and the magnetic steel is sleeved on the positioning shafts; at least two regular locking members are arranged, and the locking members fix the magnetic steel with the inner rotating shaft and the feeding shaft respectively along the axial direction.

4. The mechanical spindle with a dual layer output shaft as claimed in claim 3, characterized in that: The ball grooves are in the shape of circular holes, the balls are made of quenched alloy steel, and the magnetic steel is made of neodymium iron boron permanent magnet.

5. The mechanical spindle with a double-layer output shaft according to any one of claims 1 to 4, characterized in that: The sealing sleeve axially extending and retracting is installed between the front ends of the outer rotating shaft and the inner rotating shaft, the two ends of the sealing sleeve are limited on the outer walls of the outer rotating shaft and the inner rotating shaft through the fastening rings, and the outer rotating shaft, the inner rotating shaft and the sealing sleeve are rotatably connected.

6. The mechanical spindle with a dual output shaft according to claim 5, characterized in that: The power transmission component is a belt pulley, and the belt replacement window is formed in the rear cover.

7. The mechanical spindle with a dual layer output shaft as claimed in claim 6, characterized in that: The cylinder is installed on the rear end face of the rear cover for driving the feeding shaft to move forward and backward along the axial direction.

Images