REXRTOH CDH1/CGH1/CSH1 series milling machine type hydraulic cylinder

Technical Analysis and Application Guide for Bosch Rexroth CDH1/CGH1/CSH1 Series Hydraulic Cylinder

Product Overview and Series Positioning

Bosch Rexroth, as a leading global supplier of transmission and control technology, has launched the CDH1/CGH1/CSH1 series hydraulic cylinders, which belong to the "Mill Type" industrial hydraulic cylinder category and are designed specifically for industrial applications with high loads, high frequencies, and harsh working conditions. This series of hydraulic cylinders complies with international standards such as ISO 3320 and ISO 6022, with a rated working pressure of up to 250 bar (25 MPa) and a test pressure of up to 375 bar. They are suitable for metallurgy, mining, ships, heavy machinery, presses, and various industrial automation systems.

The three sub series CDH1, CGH1, and CSH1 maintain consistency in their basic structure and adopt differential cylinder design. The piston diameter range covers 40 mm to 320 mm, and the piston rod diameter extends from 22 mm to 220 mm, with a maximum stroke of up to 6 m. The main difference among the three is their functional configuration: CDH1 is the standard type, CGH1 focuses on high dynamic and servo applications, and CSH1 has a built-in magnetostrictive position measurement system, suitable for closed-loop control scenarios that require high-precision position feedback.

Core technology and structural characteristics

1. High voltage bearing and sturdy structure

This series of hydraulic cylinders adopts a flange connected cylinder head and cylinder bottom design, with strong structural rigidity and the ability to withstand high axial and radial loads. The surface of the piston rod is provided with a hard chromium coating or a double-layer treatment option of "hardening+hard chromium", significantly improving wear resistance and corrosion resistance, suitable for harsh environments. The cylinder barrel is made of precision cold drawn steel pipes, and the inner surface is polished to ensure low friction and long service life.

2. Various installation forms

Provide six standardized installation methods to cover the vast majority of industrial installation needs:

MP3/MP5: The base is equipped with joint bearings or self-aligning fork heads, which can compensate for certain installation alignment errors.

MF3/MF4: Front or rear circular flange installation, suitable for fixed high rigidity connections.

MT4: Ear shaft installation, allowing cylinder body to swing.

MS2: Foot mount installation, fixed to the base with bolts.

3. Intelligent buffering system

Adjustable or self-adjusting buffer devices are integrated at both ends of the cylinder body, effectively reducing the impact at the end of the stroke and protecting the cylinder body and load structure. The buffering performance can be calculated and selected based on load mass, motion speed, and system pressure, especially suitable for high-speed and high inertia applications.

4. Advanced sealing technology

Multiple sealing kit options are provided based on the working medium (mineral oil, water ethylene glycol, phosphate ester, etc.) and operating conditions (temperature, pressure, speed), including standard type, low friction type, heavy-duty type, and servo specific type. Sealing materials include NBR, FKM, etc., ensuring compatibility and long lifespan in different media.

5. Integrated sensing and control interface

The CSH1 series is equipped with a non-contact magnetostrictive displacement sensor that provides analog (4-20 mA, 0-10 V) or digital (SSI, PROFIBUS, IO Link, PROFINET) outputs with a resolution of up to 1 µ m and supports high-precision position closed-loop control.

Optional inductive proximity switch for endpoint position detection.

Standard anti loosening exhaust plug, and can be equipped with measuring connector for easy system exhaust and pressure detection.

Key technical parameters and performance

1. Load and force calculation

Based on the piston diameter and system pressure, the theoretical thrust and tension can be accurately calculated. For example, a piston diameter of 100 mm can generate a thrust of approximately 196 kN at a pressure of 250 bar. In actual selection, efficiency, accessory load capacity (such as joint bearings, flanges), and safety factor should be considered.

2. Match motion speed with flow rate

The maximum movement speed of the hydraulic cylinder is limited by the size of the inlet oil circuit and the recommended flow rate (usually 5 m/s). For example, when a piston diameter of 100 mm is paired with a G1 interface, it is recommended that the maximum speed should not exceed 0.20 m/s. Attention should be paid to the possible loss of medium carrying caused by the difference in extension and retraction speed.

3. Bending resistance and stroke verification

The allowable stroke length of hydraulic cylinders is not only limited by mechanical structure, but also requires stability (buckling) verification of the compression rod. The manual provides a calculation method based on Euler and Tetemeyer formulas, and provides detailed safety travel tables for different installation methods (fixed guided, free fixed, etc.) and load angles (0 °, 45 °, 90 °), which is an indispensable part of the selection process.