JPS5996226A - Linear motion type rolling bearing block consisting of low alloy steel and method and device for hardening surface of its ball raceway track - Google Patents

Abstract

PURPOSE:To reduce cost and to assure the mechanical property better than the mechanical property of conventional products by forming a surface hardened layer to a prescribed depth by a high frequency induction heating means only in the ball raceway track on the inside circumferential wall of a hollow block having a prescribed shape formed of alloy steel. CONSTITUTION:A hollow block B having a prescribed shape is formed of a low alloy steel and is subjected to annealing so that a surface hardened layer is formed to a prescribed depth only in the raceway tracks T1-T4 of balls when the block B slides, via a ball bearing BB, on the prescribed surface of a guide rail GL. The formation of the surface hardened layer is accomplished by inserting a high frequency induction heating coil C' into the opening of the block B, and positioning the extension part C'rl of a heating conductor C'r so as to face the respective raceway tracks T1-T4 apart therefrom at a prescribed space. Thereupon the surface layer of the tracks T1-T4 is heated and thereafter a cooling fluid is injected from a cooling jacket J to harden said layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a linear motion type roller bearing block made of low alloy steel, a method for hardening the ball raceway surface thereof, and a hardening apparatus.

A linear motor 7 sits on a linear guide rail and slides on the guide rail while making contact with and transferring bearing balls built into a predetermined surface of the guide rail.
Yong-type roller bearing blocks are conventionally made of high-grade steel such as high carbon chrome bearing steel, such as S.u.J. The manufacturing method is to form the above-mentioned steel material into a concave block by forging, etc., and after the block is completely burnt and sweetened,
The process involves applying quenching and tempering heat treatment to increase mechanical strength, and then polishing and finishing the ball IWL path.

By the way, since high carbon chrome bearing steel is an expensive material, the cost of raw materials is high. Moreover, in the manufacturing process, heat treatment is performed using an electric furnace, etc., and as shown in the bearing steel quenching temperature time curve (for 30 m 1 n/25 h) in Figure 1, the heat treatment time is only 1 yen for a long time. The heat treatment involves heating the entire material with a unique concave shape, so even if bearing steel is used, which is said to have low heat treatment distortion, the spacing between the concave openings should not be narrowed due to heat treatment. However, even if the above-mentioned molding is performed in anticipation of this, the amount of distortion will differ for each block, so in the end, each block will have a predetermined amount of distortion in the grinding process. Currently, it is extremely time-consuming to obtain accurate dimensions, which increases the manufacturing cost of the finished product.

The present invention has been made to solve the above-mentioned problems t7'J4 existing in conventional linear motion type roller bearing blocks, and as a result of using relatively inexpensive steel materials, short time and low distortion heat treatment, and low distortion. The objective is to provide a linear motion type roller bearing block which is effective in shortening the time of the polishing process, has low I, 11ξ, and guarantees mechanical properties better than conventional products.

The invention will be described in detail below.

First, in the present invention, the steel material used is replaced with the conventional high carbon chrome bearing steel, for example, S CM440- or 5Cr43
Relatively low-grade low-alloy steel such as 8 grade, and even cheap 11 grade 55
Use the remaining 0C-i or S5.5C;

Using the above-mentioned steel materials, a concave block B having a predetermined shape as shown in FIG. Only the trajectory T1, T2, T3, and 14 portions of the ball when it fully slides on a predetermined surface are surface hardened by the method and apparatus described later, and as shown in FIG.
In b), a quenched hardened layer of a predetermined depth shown as h is completely formed,
Also, a heat shadow layer is formed behind the predetermined hardened layer. This imparts 11iii wear resistance to the ball raceway, as well as imparts mechanical properties against uneven loads that the roller bearing block receives, that is, full torsional resistance, and satisfies all the conditions that should be met by the roller bearing block. −
Since this heat treatment is localized, almost no heat treatment distortion occurs and the distance between the legs Bf-Bf does not decrease.

So let's take a look at an extremely small opening space in a block.
fl on the inner circumferential wall surrounding the surface 20-25mm x 50-70mm
A ball trajectory with e-stripes, this "easy match T, ~'■゛, 4
Article...Only to Nyoiro]! The following explains how to form the entire surface hardened layer of a certain depth in 9 degrees. Since the surface hardening is like ↑1j, it is of course preferable to use high-frequency 1-conduction heating means.

Therefore, in the process of arriving at the present invention, the inventor attempted to
The heating conductor C'r of the spiral heating coil C' is inserted into the opening space from the direction of the end surface of the concave block, parallel to the bottom surface of the inner wall, and the heating coil has the shape shown as C' in FIG. As a first step, each of the extending portions C'rl of the heating conductor C'r is made to face the ball trajectories T1 and T4 at a predetermined gap as shown by the solid line in FIG. 3(b), and the ball trajectories T , and the entire surface layer of T4 is heated at a constant quenching temperature of 19T, and cooling fluid is supplied from the cooling jacket J? :
Then, as a second step, the extended portion C'rL of the heating conductor C'r is separated from the ball orbits T2 and T by a predetermined gap as shown in FIG. 3(b). In the facing arrangement i; IL, the entire surface layer of the balls 1 and T2 and T4 was hardened by the same process as described above.

In the above test results, ball trajectories T1, T2, T3 and T
4 respectively (C and \ wide surface-hardened thread parts are formed. However, the extending parts C'rl and C
'rlf Although the length of the block B was set to be sufficiently longer than the same length, in the second step, the opening end face edge B, which is a part of the bottom surface of the inner peripheral wall shown as BL in FIG. 2(b) that does not require hardening.
E generates heat and is suddenly put into n''6 due to cooling, which is not a good situation.
The induced currents that flow in opposite directions t′- are as follows: iuu path T
2.T, which extends opposite to each other and is formed into a loop.It is drawn by the current flowing through the open part C'rx of the thermal conductor C'r, and is intensively written on -y111 (plane This seems to be the result of the flow flowing to the edge BE, and a preventive measure is required.It is a trench, an extension of the heating conductor C'r
High-frequency magnetic flux p with different polarity is generated from the extended portion with a distance between L.

・Since the spacing is such that each of ω2 faces in the direction of interest, both extending portions C'r l-C when the force is 0 and the heat transfer
Cold-cut J jacket J all placed in the middle of 'r t'il
If you leave it on, the cooling jacket l-J will also heat up. In order to completely anchor this, the cooling jacket should be positioned υ゛5" above the opening of the Jf block B when facing the heating, and it should be opened 1" when cooling.
If? ? In addition, the amount of displacement is different between the first and second steps (A construction and operation are complicated and unsuitable.
! It is also not desirable that the quenching process is two steps.

Based on the above test results, the present inventors have invented a hardening method and a hardening device δ that can simultaneously harden only a plurality of ball orbits in the dipping process and do not cause edge hardening.

This will be explained according to the embodiment shown in FIGS. 4(a) to 4(d).

What is shown as C in FIG. 4 Ca) is a heating coil in the quenching apparatus of the present invention. The heating coil C is connected to a high-frequency power source (not shown), and is connected to a heating coil (2).
r and self-cooling cold gradient water 1j1. Salary and]
It consists of IP+ and P2. The lead part R is sandwiched between the insulating plate S and the lead RA on one side and the lead R on the other side.
The heating conductor Cr of the present invention, which is made of solid material, is shown in Fig. 3 as C'r.
Unlike the normal heating conductor C'r shown as , there are two heating conductors C on one side of the lead R
Connect one end of each of r1 and Cr2, and apply the force n
Thermal conductors Cr (and Cr2) are each refracted at the labial angle in opposite directions to each other for a predetermined distance, and then refracted at the labial angle in the direction of the third row to become the heating target. The ball trajectory of block B TK hits the feldspar, extends, bends in the direction of each other, then reverses in a U-shape, closes the loop, and goes backwards, and the above extended part and ball trajectory The wires are bent and extended, for example, parallel to each other in the vertical direction, with a predetermined interval corresponding to the width between them, and the other end of each is connected to the lead RB on the other side of the lead portion R.
-2 The inversions forming a U-shape are configured such that they invert each other in opposite directions. That is, as shown in FIG. 4(a), the heating conductor C
If the lower extending portion Cr1d in r is connected to the lead RA and the upper extending portions Crl+ and + are connected to the lead RBK, then the upper extending portion Cr in the heating 57 body Cr2 is connected to the lead RA.
2u! 444 is formed so that the downwardly extending portion Cr2d is connected to the lead RBK. Therefore, the high frequency 'L[
The flow b becomes the flow shown by the arrow, and the polarity of Cr1u becomes the phase M
Unlike that of r, d and Cr2u, the polarity of Cr1d is of phase j4 Cr). Unlike that of u and Cr2d, the polarity of Cr1d is
The polarity of r2u is in phase with Cr2d and Crl u
Cr2u is different from that of Cr2u, and the polarity of Cr2d is also phase 1 phosphorus.
and Cr1d.

The above-mentioned addition iQ34 bodies Cr and Cr2 are connected to leads RA, while M"1Lii are respectively connected to pipes P1, which are, for example, self-destructive cooling fluid I, supply fields, and leads RB
The other Mi+ri connected to, for example, self/1)
It is connected to a pipe P2 for discharging a cooling fluid for cooling, so that the self-heat generated at times is absorbed by the cooling fluid flowing inside the pipe.

FIG. 4(b) 3.I shows the cooler J used in this embodiment.
This algae cooler J has a heating conductor C shown in Fig. 4(a).
r) and Cr2 each with four parallel extending portions cr,
u, Cr1a, Cr2 u and Cr2d exhibit a similar square shape that can be accommodated in a quadrangular nitrogen space,
On each of the opposing side surfaces Js and Js, a plurality of cooling fluid injection holes are provided over an area corresponding to the lip of the extension part of the heat conductor Crl °Cr2, each having a predetermined length. A hole e is provided. The cooling fluid is supplied into the cavity of the cooler J from a hose (1) provided on the top surface of the cooler J, and can be injected at a predetermined pressure through two injection holes (e) on both sides.

As shown in FIG. 4(c), the heating coil C and the cooler J are fixedly arranged with the cooler J housed in the center of the heating body part Cr.

A case where only the ball orbits of a linear motion type roller bearing block are hardened using a hardening device consisting of four components (ii) and (ii) will be described below.

The block f3f, which is the material to be heat treated, has its opening facing upward and is advanced in the direction of the heating coil C with one opening end side first, as shown by the arrow in Fig. 4(c), to heat the space within the space between the concave molds. The heating conductor portion Cr of the coil C is accommodated. In this state, the heating conductor portion Cr is bent as described above for each of the heating conductors Cr1 and Cr2' (i7), so that the respective trajectories T in the block B as shown in FIG. Heating conductor i′1l
The respective extension parts in SCr are: the track T1 has an extension part Cr1u, the track T2 has an extension part Cr1d, the track T,
is the extension portion Cr2. d, and the trajectory T4 is the extension part Cr2u
In this way, they face each other with a predetermined gap between them. Next, a power source (not shown) is turned on to supply a cylinder frequency wave current of a predetermined frequency and a predetermined output to the heating coil C. [7JI] of the heating coil C] A temporary current flows in each of the heating barrels cr and Cr2, and the extending portion dielectrically heats the orbit of the block B facing the opposing extension portion. In this case, as mentioned above, the extending portions Cr1u and Crl of the heating conductor Crl
d. The extending parts Cr2u and Cr2d of the heating conductor Cr2 extend in parallel, facing the track that maintains the opening of about 10 nm, for example, so that the extending parts Cr1u and Cr1d and Cr2u and C The mutually opposite magnetic fluxes generated from 'r2d cancel each other out, and Cr1u
A similar phenomenon occurs between Cr1d and Cr2a, and the extension part Crlus Cr1ds Cr2u and Cr2d have opposing trajectories T1, T2, T,
Only the orbits 1 and 111 are heated by induction, and the orbit 111 is not heated at all. In addition, the cooler J, which is fixedly arranged in the central space of the sword mouth heating body part Cr, is the heating coil C'
As shown in , it is not located in the middle of the heating conductor C'r, and is located outside of each of the heating conductors Crl and Cr2, so the magnetic fluxes are not mutually exclusive.
It is extremely unaffected by the generated magnetic flux and generates almost no heat. Furthermore, the induced currents induced in the surface layer of each of the tracks T2 and 'r3, which flow through each other, are generated in the extending portions of the block opposite to the tracks T2 and T3, respectively.
Since r2d is refracted to the labial angle and reversed in the opposite direction to form a loop, it does not twitch intensively along the y1i1 gastric flute edge BE, and there is no risk of heat generation.

When the temperature of the track surface layer reaches a predetermined quenching temperature, the current is turned off and the cooling fluid is supplied to the cooler J through all the hoses 11 from a cooling fluid supply source (not shown). The cooling fluid is injected from the cooling fluid injection hole e at a pressure of 52, and the pupil between the upwardly extending portion Cr1u and the downwardly extending portion Cr)d of the heating conductor Crl;
The heating conductor Cr2 passes through the gap between the upper extending part Cr2u and the lower extending part Cr2d, collides with the opposing inner wall of the block B, splits vertically, flows on the wall surface, and reaches a predetermined quenching temperature. Trajectory T1 heated by
- Reaches T2, T3, and T4, and is rapidly cooled and quenched. The hardened block B is carried out from the hardening device and the hardening process is completed. The time required during this time is, for example, 5 to 10 seconds for 1 d of heating and 10 to 15 seconds for rapid cooling and quenching.
sec, so even if you include the loading/unloading time of block B, it is within 60 sec.

After the quenching process, the flock B is tempered in the same manner as before, and is made into a finished product through the grinding process.

The inventor conducted many quenching experiments to fully confirm the effects of the present invention. One example is shown below.

Example (1) Specimen; 511il] Species S 55. C Using the above-mentioned steel type, a block B having the following dimensions similar to that shown in FIG. 2(b) was formed through forging, annealing, and cutting steps.

External dimensions: 12'0 x 110 x 60 Inner throat dimensions: 50 x 20 mm It is ji.

Frequency: 80K HZ Output: 150KW Current time: 9 seconds Cooling time: 10 seconds Coolant pressure: 3 to 7/c71i (1 change of 0.5% solid fluid), (3) Experimental results; shown in Figure 5 (a) and (b) It was exactly 1. FIG. 5(a) shows a cross section of the specimen after the hardening hole has been completed, and shows the trajectories T, , T21. It was confirmed that independent surface IM hardening layers were formed in each of T3 and T4, as shown by the extra line. Figure 5(b) shows the results of hardness measurements taken at multiple points from the surface in the direction of the arrows for each 11νL path, with the horizontal axis representing the distance from the narrow surface (-) and the vertical axis representing the hardness measurement results. It is plotted at the coordinates taken from HVJ.
It was confirmed that there was a hardened layer with Hv 500 or more up to a depth of 43.5 Tmn, and of particular note, the formation of a heat-affected layer with Hv 300 or more up to a depth of 43.5 Tmn on the trajectories T1 and T4 near the tip of the leg. It was confirmed that 4j4p was observed.

Furthermore, between the legs before and after quenching There is no change in the distance between There was no formation of υ′L layer on both sides 111 and the edge.

Next, 'D1 at a depth of 0.5 from the surface of the orbit T4.
and a hardened layer, a heat-affected layer at a depth of 3.0 cm, and 6.
Microscopic photographs of the grain structure of the 5 + nm q section are shown in FIGS. 6(a), 6(b), and 6(c), respectively.

From the above experimental results and micrographs, the present invention is capable of forming a surface hardening layer only on the inner wall raceways surrounding very small walls, and especially after the surface hardening layer on the raceways T1 and T4 near the legs where unbalanced loads are applied. The remarkable heat-affected layer formed on the back is caused by rapid heating and cooling, and the 1'1 weave is fine-grained and has high toughness, so it twists at the tip of the leg 1f1i1
It was revealed that he was going to do full strength JJ. It was also confirmed that the present invention completely eliminates the occurrence of heat treatment distortion.

In the above embodiment, the case where the number of orbits is four has been explained, but it goes without saying that the present invention can also be applied to the case of a flock having six orbits, for example. In this case −
Actual measurement - There are three heating conductors Cr continuous from lead RA to the other side lead RB, and if there is an injection hole of cooler J, n is also 3.
It may be a surface.

The present invention utilizes an inexpensive carbon chrome bearing tube 1'1 to reduce the cost of manufacturing a linear motion roller bearing block, which is expensive to manufacture due to the lengthy heat treatment and polishing steps. A quenched hardened layer with a depth of 19 mm is formed only on the ball path by using low-alloy steel of 1lIII and applying strain-free and short-time local surface heat treatment using the quenching method and quenching device described in detail in Section 2. At the same time, the torsional strength is imparted to the rear part of the predetermined ball track to satisfy the conditions necessary for roller bearing blocks. It is possible to eliminate the complexity of expected dimensions during block molding by predicting the length of heat treatment time and heat treatment distortion, as well as the complexity of the grinding process, making it possible to manufacture with a short and simple manufacturing process. Therefore, manufacturing costs can be significantly reduced, and this will have a very significant effect on the spread of linear motion roller bearings.

[Brief explanation of the drawing]

Figure 1 is a quenching temperature and time curve diagram when hardening high carbon chrome bearing steel conventionally used in linear motion type roller bearing blocks, and Figure 2 (a) is the shape kd of linear motion type roller bearing blocks.
FIG. 2(b) is a perspective view for clarity, and FIG. 3(a) is a partially cutaway perspective view showing the hardened portions and hardened layers applied to the ball trajectory of the plotter in FIG. 2(a). Figure 3(b) is a perspective view of the seven heating coils used in the test of the inventive process, and Figure 3(b) is a test using all of the heating coils shown in Figure 3(a). 4(a) and (b) are respectively perspective views showing the heating coil and cooler of the quenching apparatus of the present invention, and FIG. 4(c) and (d) respectively. ) is a side view and a cross-sectional front view for explaining the Yang alloy in which the heating coil and cooler shown in FIGS. 4(a) and (b) are combined and fixedly arranged to harden the ball orbits, and FIG. 5( a) is a cross-sectional view of the specimen showing the result of injecting sound b″L into the specimen by the hardening apparatus of the present invention, and FIG. 5(b) is a cross-sectional view of each ball orbit hardening layer shown in FIG. 5(a). Figures 6 (a), (b), and (c) are detailed photographs of the hardened layer, heat-affected layer, and substrate structure, respectively. Ito 1 Single-headed person Koshuha Netsuren Co., Ltd. Agent Patent Attorney Hirohiro Kobayashi, -5:F〉: (C1) Figure 5 (b)

Claims (1)

[Claims] 1.) A low alloy characterized in that only the ball orbits on the inner circumferential wall of a concave block made of a hardenable steel material and having a predetermined shape have a surface hardening layer of a predetermined depth. A linear motion roller bearing block made of steel. 2.) When inserting at least 4 or more thread parts υ″6 over the entire surface of the inner circumferential wall of the concave block extending in the longitudinal direction, the heating conductors of the high frequency induction heating coil should have mutual polarity. They are arranged at a predetermined interval along each of the plurality of lines rfls so that they are energized differently, and only the lines of the same number are connected to the same gjj(tt (Table I1
1. A method for hardening the ball raceway surface of a linear motion roller bearing block made of low-alloy copper. 3.) In the case where at least four or more thread parts extending in parallel to the longitudinal direction of the inner circumferential wall of the concave block are fully surface hardened, from one side lead where the polarity of the lead part connected to the high frequency power source is different. A plurality of continuous heating conductors are provided in which all loops are formed to the other side lead, and each of the plurality of loops of the plurality of heating conductors is formed so as to extend opposite to each other with a predetermined gap apart from two of the above-mentioned strip portions. In addition, the heating coil is formed such that the extending portions thereof are directly connected to the leads having mutually different polarities, and the wall surface is provided with a plurality of injection holes, and a predetermined pressure is emitted from the injection holes on each wall surface. The cooling fluid injected at the heating conductor passes through each of the predetermined gaps in the plurality of IB1 gaps formed between the plurality of extension parts of the plurality of heating conductors, so that the cooling fluid can protrude into the inner circumferential wall of the block (1 degree). A roller raceway surface hardening device for a linear motion type roller bearing block made of low-alloy steel, characterized by comprising a cooler made of steel. Claim 3, characterized in that the loop closing position of each of the heating conductors extending in opposite directions to form a complete loop is sufficiently far away from the strip portion in the labial angle direction. A ball raceway surface hardening device for linear motion roller bearing blocks as described in .