How to set a limit for sprite movement?

Hi, i’m trying to do a 2d Game.
How can i set a min/max limit on the X/Y axes if I use this type of code(Movement by dragging the finger on the screen)?
There is a tentative with : &&transform.position.y < maxHeight - doesn’t work.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Move : MonoBehaviour
{
    private Vector3 touchPosition;
    private Rigidbody2D rb;
    private Vector3 direction;
    private float moveSpeed = 15f;

    public float maxHeight;
    public float minHeight;

    // Use this for initialization
    private void Start()
    {
        rb = GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
    private void Update()
    {
        if (Input.touchCount > 0 && transform.position.y < maxHeight || transform.position.y > minHeight)
        {
            Touch touch = Input.GetTouch(0);
            touchPosition = Camera.main.ScreenToWorldPoint(touch.position);
            touchPosition.z = 0;
            direction = (touchPosition - transform.position);
            rb.velocity = new Vector2(direction.x, direction.y) * moveSpeed;

            if (touch.phase == TouchPhase.Ended)
                rb.velocity = Vector2.zero;
        }
    }
}
  if (Input.touchCount > 0 && transform.position.y < maxHeight && transform.position.y > minHeight)
        {