Spindle machining system

Abstract

This invention discloses a spindle machining system to solve the technical problems of complex structure, high manufacturing cost, and axial movement that easily affects machining accuracy inherent in double-sided constraint toolholders. The system includes a machine tool spindle and a double-sided constraint toolholder. The double-sided constraint toolholder comprises a flange ring, a tapered portion, and a pull hook. The flange ring is disposed on the outer circumference of the toolholder and is used for axial engagement with the front end face of the inner tapered hole of the machine tool spindle core. The single-sided taper angle of both the outer tapered surface and the inner tapered hole is 4°-6°. A hollow structure is machined within the tapered portion of the toolholder to allow for axial elastic deformation of the flange ring, with an axial displacement of 0.01mm-0.08mm, between the locking and releasing of the pull hook by the toolholder locking and releasing mechanism in the machine tool spindle, when the outer and inner tapered surfaces are radially engaged and the flange ring is axially engaged with the front end face of the inner tapered hole of the spindle core. This ensures the effectiveness of the double-sided constraint, and the toolholder structure is simple and has low manufacturing cost.

Description

Technical Field

[0001] The present invention relates to a spindle machining system, a double-sided constraint tool holder for a machine tool spindle, and a machine tool spindle. Background Technology

[0002] In existing spindle machining systems, the connection method between the tool holder and the machine tool spindle directly affects machining accuracy and efficiency. Traditional tool holders are positioned with the machine tool spindle only through a radial fit of tapered surfaces (typically a taper ratio of 7:24, which translates to a single-sided taper angle of approximately 8°). These tool holders have a hook at the tail, which is locked and released by a tool holder locking and releasing mechanism in the machine tool spindle for tool holder installation and removal. Due to the lack of sufficient axial constraint, these tool holders are prone to axial movement under high-speed cutting conditions, affecting machining accuracy.

[0003] To address this issue, the industry has developed a double-sided constraint toolholder. This toolholder achieves dual radial and axial positioning by connecting the toolholder to the machine tool spindle through a radial fit between the inner tapered hole of the machine tool spindle core and the outer tapered surface of the toolholder's tapered section, and an axial fit between the front end face of the machine tool spindle core and the flange ring on the outer circle of the toolholder. However, existing double-sided constraint toolholders have a taper ratio of 1:10, which translates to a single-sided taper angle of slightly over 2°. The main purpose of this design is to avoid interference between the radial fit and the axial fit. However, due to the small taper angle, high machining accuracy is required, leading to significant machining difficulty. To reduce machining difficulty, the tapered section of the toolholder is designed to be shorter, thus eliminating the original pull hook. A more complex structure is designed inside the tapered section to connect with the toolholder locking and releasing mechanism. During locking and releasing, the axial elastic deformation of the toolholder is often ≥0.12mm and is difficult to control due to the influence of the machining accuracy inside the tapered section. Therefore, this type of double-sided constraint tool holder has high manufacturing costs and is expensive to sell. Summary of the Invention

[0004] The purpose of this invention is to provide an improved spindle machining system, a double-sided constraint tool holder for a machine tool spindle, and a machine tool spindle. This spindle machining system and the double-sided constraint tool holder for a machine tool spindle address the technical problems mentioned in the background art, such as complex structure, high manufacturing cost, and the tendency of traditional tool holders to experience axial movement that affects machining accuracy. Furthermore, this machine tool spindle can improve the structural strength of the front face of the spindle core when there is an axial fit between the front face of the spindle core and the flange ring on the outer circle of the tool holder.

[0005] In one aspect, a spindle machining system is provided, including a machine tool spindle and a double-sided constraint tool holder. The double-sided constraint tool holder includes a flange ring, a tool holder tapered portion, and a pull hook. The flange ring is disposed on the outer circumferential surface of the tool holder and is used for axial engagement with the front end face of the inner tapered hole of the machine tool spindle core. The tool holder tapered portion is located behind the flange ring, and its outer circumferential surface forms an outer tapered surface for radial engagement with the inner tapered hole. The pull hook is disposed at the tail end of the tool holder tapered portion and is used for locking and releasing by a tool holder locking and releasing mechanism in the machine tool spindle; the single outer tapered surface... The taper angle of the side and the taper angle of the inner taper hole are both 4°-6° and the machining accuracy grade of these taper angles is AT5 or higher. The tool holder taper is machined with a hollow structure. The hollow structure allows the tool holder to produce an axial elastic deformation of 0.01mm-0.08mm between the locking and releasing mechanism of the tool holder in the machine tool spindle and the radial fit between the outer taper surface and the inner taper hole and the axial fit between the flange and the front end face of the inner taper hole of the shaft core.

[0006] As an optimization and / or instantiation of the spindle machining system of the first aspect mentioned above, further: the single-sided taper angle of the outer conical surface is set with a tolerance setting of positive upper deviation and zero lower deviation; the single-sided taper angle of the inner conical hole is set with a tolerance setting of zero upper deviation and negative lower deviation.

[0007] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the single-sided taper angle of the outer conical surface and the single-sided taper angle of the inner conical hole are both 5°.

[0008] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the hollow structure is such that when the outer conical surface is radially engaged with the inner conical hole and the flange is axially engaged with the front end face of the inner conical hole of the shaft core, between the locking and releasing of the hook by the tool holder locking and releasing mechanism in the machine tool spindle, the tool holder generates an axial elastic deformation capable of causing the flange to have an axial displacement of 0.02mm-0.05mm.

[0009] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the double-sided constraint tool holder is made of martensitic stainless steel.

[0010] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the hollow structure is formed by a blind hole coaxially disposed in the tapered portion of the tool holder.

[0011] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the blind hole is formed by turning.

[0012] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the diameter of the blind hole changes accordingly with the diameter of the outer conical surface.

[0013] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the wall thickness of the tapered portion of the tool holder is 2mm-5mm.

[0014] As an optimization and / or instantiation of the spindle machining system of the first aspect above, further: the machine tool spindle includes: a spindle body; a spindle motor, the spindle motor including a motor stator and a motor rotor, the motor stator being fixed in the spindle body, and the motor rotor being adapted to the motor stator; a shaft core, the shaft core being rotatably mounted in the spindle body via a front bearing system and a rear bearing system and rotating with the motor rotor, the front end of the shaft core having the inner tapered hole, the front end face of the inner tapered hole extending to the front end face of the shaft core, the front end face of the shaft core being used for axial engagement with the flange ring; a front bearing system, the front bearing system including a front bearing housing and a front bearing, the front bearing housing being disposed at the front end of the spindle body, and the front bearing being mounted in the front bearing housing. The spindle body is rotatably supported at the front of the spindle core; a rear bearing system, comprising a rear bearing housing and a rear bearing, wherein the rear bearing housing is located at the rear end of the spindle body, and the rear bearing is installed in the rear bearing housing and rotatably supports the rear of the spindle core; a tool holder locking and releasing mechanism, comprising an actuator and a drive mechanism, wherein when the drive mechanism operates in a first drive mode, the actuator can lock the hook, and when the drive mechanism operates in a second drive mode, the actuator releases the hook, allowing the tool holder to disengage; the spindle core has an external flange integrally formed with the spindle core at its front end, the front bearing is installed at the rear of the external flange and is axially positioned through the external flange, and the front end face of the external flange and the front end face of the spindle core form the same plane.

[0015] This spindle machining system employs a double-sided constraint toolholder, achieving dual radial and axial positioning between the machine tool spindle and the double-sided constraint toolholder, effectively solving the problem of axial movement that is prone to occur in traditional toolholders. Simultaneously, by designing the single-sided taper angle of the outer conical surface and inner conical hole to 4°-6°, the machining difficulty is significantly reduced (compared to designs with a single-sided taper angle of more than 2°), allowing for a longer tapered portion of the toolholder. This retains the hook structure at the tail of the traditional toolholder, simplifying the internal structure of the toolholder. Furthermore, the hollow structure within the tapered portion of the toolholder allows the double-sided constraint toolholder to generate appropriate axial elastic deformation (axial displacement of the flange ring is 0.01mm-0.08mm) between the hook being locked and released by the toolholder locking and releasing mechanism in the machine tool spindle, ensuring the effectiveness of the double-sided constraint while maintaining a simple structure and low manufacturing cost.

[0016] Secondly, a double-sided constraint type tool holder for a machine tool spindle is provided, comprising: a flange ring disposed on the outer circumferential surface of the tool holder and used for axial engagement with the front end face of the inner tapered hole of the machine tool spindle core; a tool holder tapered portion located behind the flange ring and having an outer tapered surface formed on its outer circumferential surface for radial engagement with the inner tapered hole; a hook disposed at the tail of the tool holder tapered portion and used for locking and releasing by a tool holder locking and releasing mechanism in the machine tool spindle; the single-sided taper angle of the outer tapered surface is 4°-6° and the machining accuracy grade of the single-sided taper angle is AT5 or higher; and a hollow structure is machined inside the tool holder tapered portion, the hollow structure being such that when the outer tapered surface is radially engaged with the inner tapered hole and the flange ring is axially engaged with the front end face of the inner tapered hole of the spindle core, between the locking and releasing of the hook by the tool holder locking and releasing mechanism in the machine tool spindle, the tool holder generates an axial elastic deformation capable of causing an axial displacement of 0.01mm-0.08mm on the flange ring.

[0017] As an optimization and / or instantiation of the double-sided constraint tool holder of the second aspect above, further: the single-sided taper angle of the outer conical surface is 5°.

[0018] As an optimization and / or instantiation of the double-sided constraint toolholder of the second aspect above, further: the hollow structure is such that when the outer conical surface is radially engaged with the inner conical hole and the flange is axially engaged with the front end face of the inner conical hole of the shaft core, between the locking and releasing of the hook by the toolholder locking and releasing mechanism in the machine tool spindle, the toolholder produces an axial elastic deformation capable of causing the flange to have an axial displacement of 0.02mm-0.05mm.

[0019] As an optimization and / or instantiation of the double-sided constraint toolholder mentioned in the second aspect above, it is further made of martensitic stainless steel.

[0020] As an optimization and / or instantiation of the double-sided constraint type toolholder mentioned in the second aspect above, further: the hollow structure is formed by a blind hole coaxially disposed in the tapered portion of the toolholder.

[0021] As an optimization and / or instantiation of the double-sided constraint tool holder of the second aspect above, further: the blind hole is formed by turning.

[0022] As an optimization and / or instantiation of the double-sided constraint tool holder of the second aspect above, further: the diameter of the blind hole changes accordingly with the diameter of the outer conical surface.

[0023] As an optimization and / or instantiation of the double-sided constraint toolholder of the second aspect above, further: the wall thickness of the tapered portion of the toolholder is 2mm-5mm.

[0024] As an optimization and / or instantiation of the double-sided constraint tool holder of the second aspect above, further: the machine tool spindle is an electric spindle.

[0025] As an optimization and / or instantiation of the double-sided constraint tool holder in the second aspect above, further: the single-sided taper angle of the outer conical surface is set with a tolerance setting where the upper deviation is positive and the lower deviation is zero.

[0026] The aforementioned double-sided constraint toolholder achieves double-sided constraint by axially engaging the front end face of the inner tapered hole of the machine tool spindle core with the flange ring, while simultaneously engaging the outer tapered surface of the toolholder's tapered portion radially with the inner tapered hole. It employs a single-sided taper angle design of 4°-6°, achieving a machining accuracy grade of AT5 or higher, significantly reducing machining difficulty compared to designs with a single-sided taper angle of over 2°. It retains the hook structure of traditional toolholders, simplifying the connection to the toolholder's locking and releasing mechanisms. The hollow structure design within the toolholder's tapered portion ensures appropriate axial elastic deformation between the locked and released states, guaranteeing the effectiveness of the double-sided constraint while simplifying the toolholder structure and reducing cost.

[0027] Thirdly, a machine tool spindle is provided, comprising: a spindle body; a spindle motor, the spindle motor including a motor stator and a motor rotor, the motor stator being fixed in the spindle body and the motor rotor being adapted to the motor stator; a spindle core, the spindle core being rotatably mounted in the spindle body via a front bearing system and a rear bearing system and rotating with the motor rotor, the front end of the spindle core being provided with a tool holder assembly structure; a front bearing system, the front bearing system including a front bearing housing and a front bearing, the front bearing housing being disposed at the front end of the spindle body, the front bearing being installed in the front bearing housing and rotatably supporting the front part of the spindle core; and a rear bearing system, the rear bearing system including a rear bearing housing and a rear shaft. The rear bearing housing is located at the rear end of the spindle body, and the rear bearing is installed in the rear bearing housing and rotates to support the rear of the spindle core. The tool holder locking and releasing mechanism includes an actuator and a drive mechanism. When the drive mechanism operates in the first drive mode, the actuator can lock the tool holder so that the tool holder is tightly engaged with the tool holder assembly structure. When the drive mechanism operates in the second drive mode, the actuator releases the tool holder so that the tool holder can be disengaged from the tool holder assembly structure. The front end of the spindle core has an outer flange integrally formed with the spindle core. The front bearing is installed at the rear of the outer flange and is axially positioned through the outer flange.

[0028] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the tool holder assembly structure includes an inner tapered hole, the front end face of which extends to the front end face of the spindle core.

[0029] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the front end face of the outer flange and the front end face of the shaft core form the same plane.

[0030] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the tool holder assembly structure provides double-sided constraint positioning of the tool holder through the inner tapered hole and the plane.

[0031] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the single-sided taper angle of the inner taper hole is 4°-6° and the machining accuracy level of the single-sided taper angle is AT5 or higher.

[0032] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the single-sided taper angle of the inner tapered hole is 5°.

[0033] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the single-sided taper angle of the inner tapered hole is set with a tolerance of zero upper deviation and negative lower deviation.

[0034] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the plane is located at the foremost end of the machine tool spindle.

[0035] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: a front cover is installed at the front end of the front bearing housing, and the front cover and the outer flange are dynamically sealed together.

[0036] As an optimization and / or instantiation of the machine tool spindle in the third aspect above, further: the outer peripheral surface of the outer flange is provided with a dynamic sealing structure that cooperates with the front end cover.

[0037] The machine tool spindle is designed with an external flange structure that is integrated with the spindle core. The front bearing is installed at the rear of the external flange and is axially positioned through the external flange, which significantly improves the structural strength of the front end face of the spindle core. This design is particularly suitable for use with double-sided constrained tool holders, and can better withstand the axial contact force between the front end face of the inner tapered hole of the spindle core and the tool holder flange ring, thereby improving the rigidity and stability of the entire spindle system.

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages provided by the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice. Attached Figure Description

[0039] The accompanying drawings, which form part of this specification, are used to aid in understanding the invention. The contents provided in the drawings and their related descriptions in this specification can be used to explain the invention, but do not constitute an undue limitation of the invention.

[0040] Figure 1 This is a schematic diagram of the structure of a double-sided constraint tool holder according to an embodiment of the present invention.

[0041] Figure 2 For use Figure 1 The diagram shows the structure of a spindle machining system with a double-sided constraint tool holder.

[0042] Figure 3 This is a schematic diagram of the structure of a machine tool spindle according to an embodiment of the present invention.

[0043] The following are marked in the figure: flange ring 11; tool holder taper part 12; outer taper surface 121; blind hole 122; pull hook 13; machine tool spindle 2; shaft core 21; inner taper hole 211; outer flange 212; tool holder locking and releasing mechanism 22; front end cover 23; dial indicator 3; measuring rod 31. Detailed Implementation

[0044] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0045] The technical solutions and features provided in the various sections, including the following description, can be combined with each other without conflict. Furthermore, where possible, these technical solutions, features, and related combinations can be given specific technical subject matter and protected by relevant patents.

[0046] The embodiments of the present invention described below are generally only some embodiments and not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of patent protection.

[0047] The terms "comprising," "including," "having," and any variations thereof in this specification, the corresponding claims, and related sections are intended to cover non-exclusive inclusion. Other related terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0048] Figure 1 This is a schematic diagram of the structure of a double-sided constraint tool holder according to an embodiment of the present invention. Figure 2 For use Figure 1 The diagram shows the structure of a spindle machining system with a double-sided constraint tool holder. Figures 1-2 As shown, a double-sided constrained tool holder for a machine tool spindle includes: a flange ring 11, a tool holder taper portion 12, and a pull hook 13.

[0049] The flange ring 11 is disposed on the outer circumferential surface of the tool holder and is used to axially engage with the front end face of the inner tapered hole 211 of the spindle core 21 of the machine tool spindle 2.

[0050] The taper portion 12 of the tool holder is located behind the flange ring 11 and its outer peripheral surface forms an outer taper surface 121 for radial engagement with the inner taper hole 211.

[0051] The hook 13 is located at the tail of the tool holder taper 12 and is used to be locked and released by the tool holder locking and releasing mechanism 22 in the machine tool spindle 2.

[0052] The single-sided taper angle of the outer conical surface 121 is 4°-6° (preferably 5°), and the machining accuracy level of the single-sided taper angle is AT5 or higher.

[0053] Furthermore, a hollow structure is machined inside the tapered portion 12 of the tool holder. This hollow structure allows the tool holder to undergo axial elastic deformation, which can cause the flange 11 to undergo axial displacement of 0.01mm-0.08mm, when the hook 13 is locked and released by the tool holder locking and releasing mechanism 22 in the machine tool spindle 2, in the case of radial engagement between the outer tapered surface 121 and the inner tapered hole 211 and axial engagement between the flange 11 and the front end face of the inner tapered hole 211 of the shaft core 21.

[0054] It should be noted that the single-sided taper angle refers to the angle formed between one edge of the outer conical surface 121 and the axis of the cone portion 12 of the tool holder (i.e., the center line of the tool holder).

[0055] Traditional toolholders are positioned with the machine tool spindle only through a radial fit of tapered surfaces (typically a taper ratio of 7:24, which translates to a single-sided taper angle of approximately 8°). These toolholders have a hook at the tail, which is used to lock and release the toolholder via a locking and releasing mechanism within the machine tool spindle. Due to the lack of sufficient axial restraint, these toolholders are prone to axial movement under high-speed cutting conditions, affecting machining accuracy.

[0056] Existing double-sided constraint toolholders have a taper ratio of 1:10, which translates to a single-sided taper angle of slightly over 2°. This design, due to its small taper angle, demands high machining precision, resulting in significant machining difficulty. To reduce machining difficulty, the tapered section of the toolholder is designed to be shorter, thus eliminating the original pull hook. A more complex structure is designed inside the tapered section to connect with the toolholder's locking and releasing mechanism. During locking and releasing, the axial elastic deformation of the toolholder is large (≥0.12mm). This type of double-sided constraint toolholder has high manufacturing costs and is expensive to sell.

[0057] Table 1 shows a comparison of the relevant features of the double-sided constraint tool holder of this invention, the traditional tool holder, and the existing double-sided constraint tool holder.

[0058] Table 1

[0059]

[0060]

[0061] As can be seen from the above, the technical improvement of the double-sided constraint toolholder of this invention is as follows: the taper ratio is set as a compromise between that of traditional toolholders and existing double-sided constraint toolholders, thereby retaining a longer taper length and a hook locking method. Then, the hollow structure within the taper section ensures that the toolholder can generate a certain degree of axial elastic deformation, thus guaranteeing that the axial fit has a substantial axial positioning function. Therefore, the double-sided constraint toolholder of this invention avoids the high machining difficulty and high cost problems caused by small taper angles, while retaining the advantages of double-sided constraint and preventing axial movement of the toolholder under high-speed cutting conditions.

[0062] The detection of axial elastic deformation of double-sided constrained tool holders can be achieved using any feasible method. For example, after installing the tool holder into the inner tapered hole 211 of the spindle core 21 of the machine tool spindle 2, so that the outer tapered surface 121 is radially engaged with the inner tapered hole 211 and the flange ring 11 is axially engaged with the front end face of the inner tapered hole 211 of the spindle core 2, before starting the tool holder locking and releasing mechanism 22 in the machine tool spindle 2 (refer to the content on the tool holder locking and releasing mechanism provided by the applicant in publication number CN115740518A) to lock the hook 13, the axial position of the flange ring 11 (the relative distance between the flange ring 11 and a certain fixed reference in the axial direction of the flange ring 11) can be calibrated. Then, after starting the tool holder locking and releasing mechanism 22 in the machine tool spindle 2 to lock the hook 13, the axial position of the flange ring 11 can be calibrated a second time (the relative distance between the flange ring 11 and the aforementioned fixed reference in the axial direction of the flange ring 11), thereby enabling the detection of the axial displacement of the flange ring 11 towards the hook 13 (equivalent to the difference between the two relative distances).

[0063] Preferably, the hollow structure allows the outer conical surface 121 to be radially engaged with the inner conical hole 211 and the flange 11 to be axially engaged with the front end face of the inner conical hole 211 of the shaft core 21, so that between the locking and releasing of the hook 13 by the tool holder locking and releasing mechanism 22 in the machine tool spindle 2, the tool holder generates an axial elastic deformation that can cause the flange 11 to have an axial displacement of 0.02mm-0.05mm.

[0064] This precisely controlled axial elastic deformation, with the radial fit between the outer conical surface 121 and the inner conical hole 211 and the axial fit between the flange ring 11 and the front end face of the inner conical hole 211 of the shaft core 21, ensures that the double-sided constraint tool holder can maintain an appropriate axial preload between the locking and releasing mechanism 22 of the tool holder locking and releasing mechanism in the machine tool spindle 2 when the hook 13 is locked and released. It is neither too large, which would cause structural damage (such as insufficient tool holder strength), nor too small, which would cause the loss of axial constraint. Thus, while ensuring the effectiveness of double-sided constraint, it improves the reliability and repeatability of tool holder locking.

[0065] The double-sided constrained tool holder of this embodiment is made of martensitic stainless steel. The hollow structure is formed by a blind hole 122 coaxially disposed in the tapered portion 12 of the tool holder. The blind hole 122 can be formed by conventional turning. The diameter of the blind hole 122 can be varied according to the diameter of the outer conical surface 121 to control the wall thickness of the tapered portion 12 of the tool holder to be 2mm-5mm.

[0066] like Figure 2 As shown, the machine tool spindle using the above-mentioned double-sided constraint type tool holder includes:

[0067] Spindle body;

[0068] The spindle motor consists of a motor stator and a motor rotor. The motor stator is fixed in the spindle body, and the motor rotor is adapted to the motor stator.

[0069] Shaft core 21 is rotatably mounted in the main shaft body via a front bearing system and a rear bearing system and rotates with the motor rotor. A tool holder assembly structure is provided at the front end of the shaft core.

[0070] The front bearing system includes a front bearing housing and a front bearing. The front bearing housing is located at the front end of the main spindle body, and the front bearing is installed in the front bearing housing and rotates to support the front of the spindle core.

[0071] The rear bearing system includes a rear bearing housing and a rear bearing. The rear bearing housing is located at the rear end of the main spindle body, and the rear bearing is installed in the rear bearing housing and rotates to support the rear part of the spindle core.

[0072] The tool holder locking and releasing mechanism includes an actuator and a drive mechanism. When the drive mechanism operates in the first drive mode, the actuator can lock the tool holder so that the tool holder is tightly engaged with the tool holder assembly structure. When the drive mechanism operates in the second drive mode, the actuator releases the tool holder so that the tool holder can be disengaged from the tool holder assembly structure.

[0073] The aforementioned structure of the machine tool spindle is prior art, which can be understood from the machine tool spindle provided by the applicant in the patent document with publication number CN115740518A, and will not be described in detail here.

[0074] Among them, the taper angle of the inner tapered hole 211 is 4°-6° on each side and the machining accuracy grade is AT5 or higher, so as to be compatible with the above-mentioned double-sided constraint type tool holder.

[0075] Optionally, the single-sided taper angle of the outer conical surface 121 is set with a tolerance setting where the upper deviation is positive and the lower deviation is zero; the single-sided taper angle of the inner conical hole 211 is set with a tolerance setting where the upper deviation is zero and the lower deviation is negative.

[0076] The single-sided taper angle of the outer conical surface 121 is set with a tolerance setting of positive upper deviation and zero lower deviation, while the single-sided taper angle of the inner conical hole 211 is set with a tolerance setting of zero upper deviation and negative lower deviation. This specific tolerance configuration ensures that the actual taper angle of the outer conical surface 121 is not less than the nominal value, and the actual taper angle of the inner conical hole 211 is not greater than the nominal value. Thus, during the assembly process, the two conical surfaces first achieve a reliable radial fit, establishing a precise radial positioning reference, creating conditions for the subsequent axial fit between the flange ring 11 and the front end face of the inner conical hole 211, forming a step-by-step positioning process from radial to axial, and finally achieving a high-precision fit state with double-sided constraints.

[0077] Figure 3 This is a schematic diagram of the structure of a machine tool spindle according to an embodiment of the present invention. Figure 3 As shown, the front end of the machine tool spindle is improved. The front end of the spindle core 21 has an outer flange 212 integrally formed with the spindle core 21. The front bearing is installed at the rear of the outer flange 212 and is axially positioned by the outer flange 212. At the same time, the front end face of the outer flange 212 and the front end face of the spindle core 21 (i.e., the front end face of the inner tapered hole 211 of the spindle core 21) form the same plane.

[0078] The machine tool spindle is designed with an external flange structure 212 integrally formed with the spindle core. The front bearing is installed at the rear of the external flange 212 and is axially positioned through the external flange 212, which significantly improves the structural strength of the front end face of the spindle core 21. This design is particularly suitable for use with double-sided constraint tool holders (of course, the above-mentioned machine tool spindle is not only suitable for use with double-sided constraint tool holders), and can better withstand the axial fitting force between the front end face of the inner tapered hole 211 of the spindle core 21 and the tool holder flange ring 11, thereby improving the rigidity and stability of the entire spindle system.

[0079] Based on this, a front cover 23 is installed at the front end of the front bearing housing, and the front cover 23 and the outer flange 212 are dynamically sealed together. Specifically, the outer peripheral surface of the outer flange 212 is provided with a dynamic sealing structure that mates with the front cover 23.

[0080] A dynamic sealing structure that matches the front cover 23 is provided on the outer peripheral surface of the outer flange 212. This design ensures that contaminants such as cutting fluid and chips can be effectively prevented from entering the machine tool spindle during high-speed rotation, protecting the front bearing and internal structure. At the same time, it does not affect the normal rotation of the spindle core 21, maintaining the sealing performance and operational stability of the spindle system.

[0081] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the foregoing content of this specification without inventive effort should fall within the scope of the present invention.

Claims

1. A spindle machining system, comprising a machine tool spindle and a double-sided constraint tool holder, the double-sided constraint tool holder comprising a flange ring, a tool holder tapered portion, and a pull hook, the flange ring being disposed on the outer circumferential surface of the tool holder and used for axial engagement with the front end face of the inner tapered hole of the machine tool spindle core, the tool holder tapered portion being located behind the flange ring and having an outer tapered surface formed on its outer circumferential surface for radial engagement with the inner tapered hole, the pull hook being disposed at the tail end of the tool holder tapered portion and used for locking and releasing by a tool holder locking and releasing mechanism in the machine tool spindle; characterized in that: The single-sided taper angle of the outer conical surface and the single-sided taper angle of the inner conical hole are both 4°-6°, and the machining accuracy grade of these single-sided taper angles is AT5 or higher. A hollow structure is machined within the tapered portion of the tool holder. This hollow structure allows the tool holder to undergo axial elastic deformation of 0.01mm-0.08mm between the radial engagement of the outer conical surface and the inner conical hole and the axial engagement of the flange ring and the front end face of the inner conical hole of the shaft core, and between locking and releasing the hook by the tool holder locking and releasing mechanism in the machine tool spindle. The hollow structure is formed by a blind hole coaxially disposed within the tapered portion of the tool holder, the diameter of which varies accordingly with the diameter of the outer conical surface. The wall thickness of the tapered portion of the tool holder is 2mm-5mm.

2. The spindle machining system as described in claim 1, characterized in that: The single-sided taper angle of the outer conical surface is set with a tolerance setting of positive upper deviation and zero lower deviation; the single-sided taper angle of the inner conical hole is set with a tolerance setting of zero upper deviation and negative lower deviation.

3. The spindle machining system as described in claim 1, characterized in that: The single-sided taper angle of the outer conical surface and the single-sided taper angle of the inner conical hole are both 5°.

4. The spindle machining system as described in claim 1, characterized in that: The hollow structure allows the outer conical surface to radially engage with the inner conical hole and the flange ring to axially engage with the front end face of the inner conical hole of the shaft core. Between the locking and releasing of the hook by the tool holder locking and releasing mechanism in the machine tool spindle, the tool holder generates an axial elastic deformation capable of causing the flange ring to have an axial displacement of 0.02mm-0.05mm.

5. The spindle machining system as described in claim 1, characterized in that: The double-sided constraint tool holder is made of martensitic stainless steel.

6. The spindle machining system as described in claim 1, characterized in that: The blind hole is formed by turning.

7. The spindle machining system according to any one of claims 1-6, characterized in that: The machine tool spindle includes: Spindle body; A spindle motor, comprising a motor stator and a motor rotor, wherein the motor stator is fixed in the spindle body and the motor rotor is adapted to the motor stator; The shaft core is rotatably mounted in the main shaft body via a front bearing system and a rear bearing system and rotates with the motor rotor. The front end of the shaft core is provided with the inner tapered hole, and the front end face of the inner tapered hole extends to the front end face of the shaft core. The front end face of the shaft core is used to axially engage with the flange ring. A front bearing system, comprising a front bearing housing and a front bearing, wherein the front bearing housing is disposed at the front end of the main shaft body, and the front bearing is installed in the front bearing housing and rotatably supports the front part of the shaft core; The rear bearing system includes a rear bearing housing and a rear bearing. The rear bearing housing is disposed at the rear end of the main shaft body, and the rear bearing is installed in the rear bearing housing and rotatably supports the rear part of the shaft core. A tool holder locking and releasing mechanism includes an actuator and a drive mechanism. When the drive mechanism operates in a first driving mode, the actuator can lock the hook. When the drive mechanism operates in a second driving mode, the actuator releases the hook, allowing the tool holder to disengage. The front end of the shaft core has an outer flange integrally formed with the shaft core. The front bearing is installed at the rear of the outer flange and is axially positioned by the outer flange. The front end face of the outer flange and the front end face of the shaft core form the same plane.

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